Sustainable Horticulture

Changes Affecting Horticulture, Both Bad & Good

Posted by sustainable_hort on November 22, 2011  |  No Comments

It was May when I last posted anything. Doubling our farm, taking over as manager of our local farmers market, and unexpected contract work meant no time to write. I am sure you assumed this site died a quiet death like most sites. Ambition usually blinds bloggers to the reality of maintaining a site with original, fresh content. It is partly that…but; I wish it were only that.

Sadly, it is not. When I started this blog, the intent was to focus mainly on the nursery industry and the sustainable model I saw as a future option for growers. But, it is an industry going through radical change, and not a good one. I am working on a draft for an article discussing what has struck a vibrant, positive industry. I am seeing and experiencing it firsthand, on the rural back roads that were the heart of Oregon’s leading agricultural crop. It is a matter of survival for these growers, and not a time for taking chances with any innovation, let alone risking your present production system for one that is still being developed. More on this soon.

Still, as an organic produce grower with a horticultural degree, I see opportunities for those nurseries that can turn to more sustainable production. In the next few months I will update the “Can Nurseries be Sustainable” post (12/23/2009), including the rough tests I ran with several organic container mixes at a local nursery. The results were impressive enough that I want to see more work done in this direction.

And, this site will continue to discuss the innovative future uses of plants, particularly in urban/suburban areas. This includes the diverse “urban agriculture” movement that could change how much of our food is grown and even become a “job creator?”

But, it goes far beyond that! I have been involved in the green roof industry for five years, and, despite the current construction collapse, it is technology for the times. It is just one example of how plants are being used to solve environmental problems. Plants will be integrated into our lives in ways we have not even developed yet…just look at the urban food production skyscraper being proposed by Dr. Dickson Despommier. I will discuss his book, The Vertical Farm, soon…though I have my doubts.

Finally, though there are other sources to find general agricultural information, I will continue to comment on the limitations and negatives of large agribusiness. For instance, the expanding herbicide resistance issue has overwhelmed the promises of easy farming. Even the main stream ag press has acknowledged this, warning its readers that production will need to return to more complex systems. As usual, something that seems too good to be true, finally fails. A return to working with nature, instead of fighting it, will probably turn out to be the best economic investment farming can make.

Anyway, enough for this short post. If any of the above topics interest you, please keep tune. Its good to be back.

Nursery Industry Explores Biodegradable Containers

Posted by sustainable_hort on May 31, 2010  |  No Comments

Plastic containers revolutionized plant production. Now a significant percentage of plants are grown in some type of container. At the retail level, containers not only hold plants and soil, but they have become a visual part of the marketing.

Yet, environmental concerns increased with plastic products, both in how they are made and how they become a waste stream. So, container manufacturers began to look at other materials. The challenge was to find materials that could contain the soil and plants as they moved through the production and marketing system, yet breakdown after they were used, usually in composting systems.

Numerous substrates are being used and tested to create a range of biodegradable pots including waste paper, peat, coir, cornstarch resins, wheat, bamboo, and even cow manure.

Finding plastic replacements for containers has become an important research topic, with the American Nursery and Landscape Association (ANLA) starting research several years ago to identify useful container substrates (see below). The key challenge is finding compounds and resins that, when combined, will stand up to normal environmental pressures.

“We need materials that will stand up to the south’s warmer temperatures, heavy irrigation schedules, and high levels of nitrogen,” explained Agricultural Research Service horticulturist Donna Fare. She said these environmental factors work together to break down non-plastic pots in the field. Fare is heading up the ANLA-sponsored research project in McMinnville, Tennessee, which will finally test a chicken-feather based container during this year’s growing season.

Recycled Plastic a First Option
Many nursery container producers have morphed from using virgin plastic to using recycled materials. This is a major step toward sustainability, since it at least recovers the plastic already in use in the nursery industry, plus absorbing some of the consumer waste stream.
For instance, ITML Horticultural Products Inc. has a line of recycled containers, called Elite and Euro System Nursery Containers, made with “100% recycled, indestructible polyethylene material.”

Another example is the Root Pouch containers from Averna and Associates. These pouches are made from polyethylene terephthalate (PETE), which comes from recycled plastic beverage bottles, which are turned into non-woven fabric. It is used to manufacture a full line of nursery containers including propagation liners and various sizes of plantable pouches, available in different densities and degradable life spans.

Finally there are oxo-biodegradable products, which I have not found yet in the industry. Wikipedia defined the plastic as follows:

“Oxo Biodegradable (OBD) plastic is polyolefin plastic to which has been added very small (catalytic) amounts of metal salts. These catalyze the natural degradation process to speed it up so that the OBD plastic will degrade when subject to environmental conditions to produce to water, carbon dioxide and biomass. The process is shortened from hundreds of years to months for degradation and thereafter biodegradation depends on the micro-organisms in the environment.” I am going to look into this more, so keep reading.

What are Biodegradable Containers?

While there are differences between aerobic and anaerobic degradation, “biodegradable” is usually considered as a material can be broken down into its organic components. Essentially, biodegradable materials avoid increasing landfills by eventually returning them to the soil through effective composting.

As a note, the “effective composting” is a key step to making any of these containers actually biodegradable. In fact, some national and international standards have stricter criteria, defining compostable as having three requirements:

• First, again they must “biodegrade” which is defined as “breaking down into carbon dioxide, water and bio mass.”
• Secondly, they must “disintegrate,” so after three months of composting and subsequent sifting through a 2 mm sieve, there is no more than 10% residue remaining.
• Finally, no “eco toxicity,” so the bio-degradation does not produce any toxic material and the compost can sustain plant growth.

Unfortunately, these global standards exist to certify compostable plastics (ASTM D6400) and compostable packaging (ASTM D6868), under controlled composting conditions typically found only at industrial composting facilities. It is uncertain whether many of these new “plastics” will degrade quickly and effectively in standard landfills or backyard compost bins.

Molded Fiber Early Option

But, many decades ago, molded pulp or fiber first found uses in the horticulture industry. Molded pulp products are made from natural cellulose fibers, including waste papers and peat, and are biodegradable breaking down in compost systems and most landfills. These molded fiber products, were often used in early propagation stages in combination with rigid plastic trays.

But, as plants moved into gallon sizes, most growers continue to use plastic pots, especially if they are shipping plants. The early fiber pots were just not rigid enough to withstand damage during handling.

One of the earlier producers of non-plastic containers was active here in Oregon…Western Pulp Products. The company has more than a 50-year history of making containers using waste paper, collected by charitable organizations (“post-consumer”), while other sources are “pre-consumer,” including Kraft, waxed, and other waste paper. Only the metal rings and hanging wires are not decomposable.

“Even the wax paraffin used to bind the pulp will degrade during composting or in the soil,” said sales manager Jim Lee

While their products are not considered “organic,” they can be used to grow organic plants, according to Lee. He said their growers received approval from Oregon Tilth that organic vegetable transplants can be grown in their molded fiber containers but the plant must be removed from the container before it is planted in the soil. 


Jiffy pots are another decade-old name in nursery containers, entering the market in the mid-1950’s. The George Ball Company bought the U.S. rights from the Norwegian firm that developed the technology. They found numerous uses in nursery propagation, becoming a standard tool for growing plants. But, again, they tended to be too fragile for field and shipping uses.

Wide Range of Substrates Now Available
Many of the newer biodegradable containers are actually manufactured by processes similar to the Western Pulp method…a plant based substrate held together with a binding agent. The choice for substrates continues to expand.

One example are the Fertil biodegradable plant pots, made from 100% natural biodegradable wood fibers, composing 80% of the substrate, plus 20% peat moss. Meanwhile, Summit Plastics Company has a biodegradable line, “Eco 360,” that features containers made of corn, wheat and wood fibers.

Another company, T & R, Woodburn, Oregon, is offering a new line of containers called Ecotainable®. Manufactured by Kelmar’s Creations, the products use ‘patented’ bioresin materials, made from wheat, tapioca, potato starches and corn, to form pots and other products.

CoCo Coir Pot, made by Green Neem, is a biodegradable cultivation pot made of coconut fibers, which have exceptionally high permeability to water, air and roots. Coir products are now available through several companies.

Cow Pots is taking a different approach, using “odor-free, 100% composted cow manure” as the substrate. They claim the manure also adds more nutrition when the plant is growing or transplanted.

Fungi Grows Containers
A radically different approach is the EcoCradle products.
The new product is made from agricultural byproducts including cottonseed hulls, buckwheat hulls and rice husk that are mixed with a filamentous fungi — mycelium — as a bonding agent — and allowed to grow inside molds. The mycelium secretes an enzyme that decomposes the organic waste as it grows. After seven days at room temperature in the dark, a compact, ultra light, malleable material is formed that can resist high temperatures, according to company literature.

Downsides?
While there is an increasing availability of alternative containers, most nurseries have been slow to switch from plastic. Even Northwoods Nursery, Molalla, Oregon, well known for its many sustainable efforts, is still using plastic pots.

“We are just not sure they will hold up over a longer time frame,” said Laura O’Leary, sustainable director for Northwoods. While the nursery has implemented other “sustainable practices,” including recycling plastic containers, they are still holding back on moving to these newer options, she said. Like many nurseries, they plan to test new products, hoping to find products that prove tough.

In addition to needing perfect conditions to decompose, some manufacturers are also cautioning consumers that the pots need to be handle correctly when planting to avoid problems.

For example, Bonnie Plants, uses biodegradable pots extensively, with the smaller versions made by Jiffy. They listed the following rules for using their pots:
• To ensure success, drench the pots thoroughly just before planting.
• Remove the shrink-wrap label from the rim of the pot by cutting it with scissors.
• Also tear away the top of the pot so that the rim is not exposed above ground after planting. If the pot dries out, it can rob moisture from the roots when capillary action pulls water up to the dry rim.
• Finally, tear away the bottom half of the pot before placing the plant in its hole to exposes some roots to direct contact with the soil.

Like any new technology, biodegradable containers will need further refinement and testing to create products that growers will use confidently, especially if plants are shipped.

While there are ongoing research projects (see above) testing how well plants grow in these non-plastic choices, work done over a decade ago showed that plants would grow as well, or better, in biodegradable pots. So, it seems that chief concern remains durability. Once that is solved, biodegradable products could have a bright future in the nursery industry.

You can continue to follow this topic here. I am convinced that we will find more and more organic “waste” products that can be turned into various compostable or plantable pots and containers. Ultimately, they will prove their economic advantage.

Show Me the Research – Glyphosate and GM Problems Expand

Posted by sustainable_hort on May 24, 2010  |  No Comments

Monsanto’s PR team must be up nights…since the good news just keeps coming up around GM technology and their popular herbicide product…Round-Up. We have discussed several resistance issues recently (see both earlier “Show Me the Research” posts), but the concerns and problems are expanding.

First, Round-Up’s affects on plant health.
Microbiologist Robert Kremer USDA-ARS (US Department of Agriculture- Agricultural Research Service) was interviewed recently in the online “The Organic & Non-GM Report,” where he explained his concerns with glyphosate’s (Round-Up) impact on plant health. He was quoted as saying the compound “This system is altering the whole soil biology.” He expanded the observations, noting that “glyphosate can have toxic effects on microorganisms and can stimulate them to germinate spores and colonize root systems. Other researchers are showing that glyphosate can immobilize manganese, an essential plant micronutrient.”

In this month’s issue, the editors interviewed retired Purdue University Emeritus Professor of Plant Pathology, Dr. Don Huber. He said that glyphosate can “significantly increase the severity of various plant diseases, impair plant defense to pathogens and diseases, and immobilize soil and plant nutrients rendering them unavailable for plant use.” And that glyphosate stimulates the growth of fungi and enhances the virulence of pathogens such as Fusarium and “can have serious consequences for sustainable production of a wide range of susceptible crops.”

This all builds on an important work I have written about before…”Healthy Crops, A New Agricultural Revolution” by Francis Chaboussou. In it, he looks at 75 years of similar research on not just glyphosate, but many pesticides, herbicides and nitrogen-heavy fertilizers, and their negative impacts on disease and pest problems. I felt he showed clearly that while the compounds might solve a problem, they usually created others. Others that then required spraying of toxic compounds, which have the same affect. And the circle goes ‘round and the grower pays. Less toxic approaches might actually reduce other input costs…it at least deserves a closer, open-minded look.

GM Bt Cotton Causes Pest Explosion
And then, from China comes a report about a recent disaster that resulted from planting Bt cotton. Bt (Bacillus thuringiensis) is one of best know “natural” insecticides, with the organism successfully controlling several pest outbreaks (various caterpillars). Then, it was inserted genetically into crops, including cotton, where it offered bollworm control. And that part of the equation worked, so growers could stop spraying toxic chemicals. Looked like a win-win.

But then, the fields became infested with another pest, the Mirid Bug, causing serious damage. Scientists determined that the June spraying for bollworms had also knocked back the entire insect community, including other pest species and their natural predators. With no controls, in this case, the Mirid Bug won the race, finding a vast, rich food source, and quickly expanding its populations. It has even moved into other crops such as apples, strawberries, pears, peaches and vegetables, where it had never been a problem. All this started following the switch to Bt crops in 1997, showing up first in cotton in 2000, and moving to other crops by 2005. It seems their only short-term answer is go back to spraying, after paying more the Bt-cotton.

So, again unintended consequences. The GM technology still holds promise to help with world nutrition. The idea and reality of foods that create extra vitamins (improved rice variety) with the help of added genetic information could save lives. But, first it is caution with this new “tool.” It needs more study, more testing in the complexity of an environmental system, to understand those consequences. From these latest reports, it seems to solve single problems only to create others. Not a sustainable system.

For more:
• “Scientist warns of dire consequences with widespread use of glyphosate”, The Organic & Non-GMO Report, May 2010, @ http://www.non-gmoreport.com/articles/may10/consequenceso_widespread_glyphosate_use.php

• “Scientist finding many negative impacts of Roundup Ready GM crops, USDA doesn’t want to publicize studies showing negative impact2, The Organic & Non-GMO Report, January 2010, @ http://www.non-gmoreport.com/articles/jan10/scientists_find_negative_impacts_of_GM_crops.php

Trees for CO2 Sequestration?

Posted by sustainable_hort on April 14, 2010  |  No Comments

(This is the first part of a two-part post on trees and CO2 sequestration, which looks at whether trees actually play a positive role. The second part will discuss the actual trees we should be using for this perceived benefit)

Trees can play an important, positive role in helping control the amount of carbon dioxide (CO2) in the atmosphere by absorbing that key greenhouse gas. The process, called “sequestration,” uses a tree’s photosynthesis to convert the problematic greenhouse gas to cellulose and oxygen.

As this concept has become more widely accepted and, as researchers continue to document trees’ benefits, it may expand market for some nursery crops. But, is all this excitement warranted, or do some recent questions contradict the enthusiasm?

What We Need to Know
The crucial questions at this stage become “does sequestration really work,” and if so, “which trees are most efficient at sequestration?” Research continues to delve into varietal and climate issues that affect how well a specific tree will capture CO2.

“We can certainly argue that trees, when they absorb CO2, buy us a period of sequestration,” said David Nowak, researcher at SUNY-CESF, Syracuse, New York.

But, Nowak, who has lead several major sequestration studies, points out there are many variables that need to be studied, including climate effects, tree species and age, and even the general maintenance issues.

“These all can impact the effectiveness of a tree to sequester CO2,” he said.

Other research has pointed out some distinct differences based on climate. In fact, recent computer models are even speculating that non-tropical trees might even increase planet temperatures.

But, planting trees in [any] climate is better than not. So, how does it work and what does research indicate as the best options for using trees to reduce atmospheric CO2?

What is Sequestration?…Removal of Air Pollutants
Air pollution can be reduced dramatically when plants take up CO2 and many airborne particles through their leaf stomata. Some other gases are removed by the plant leaf and stem surfaces. Gases absorbed by the plant stomata later diffuse into intercellular spaces. They then are absorbed and react with water films to form acids, or they react with inner-leaf surfaces. Some particles can be absorbed into the tree, though most particles that are intercepted are retained on the plant surface.

Some polluting particles may return to the air during transpiration or be washed off by rain. Later, the leaf and twigs may drop off the to the ground and start to decompose. This also releases some of the CO2 back, which offsets some of the early gains. Consequently, vegetation remains only a temporary site for retaining many atmospheric particles.

Benefits of Trees
Plant-It 2020 uses a ‘scientific estimate’ to develop the following statistics based upon the tree species, soil conditions and tree-planting methodology,

Their research indicated that 600 trees in the tropics would fill one acre, which could sequester up to 15 tons of CO2 annually. Other statistics include 40 trees (common varieties) will sequester one ton of CO2 each year; and that one million trees covering 1,667 acres could capture 25,000 tons of CO2 annually.

Research in major metropolitan areas showed the urban forests could have an impact. It was reported by David J. Nowak in “The Effects of Urban Trees on Air Quality” showed that in 1994, trees in New York City removed an estimated 1,821 metric tons (t) of air pollution at an estimated value to society of $9.5 million.

His research showed that while New York’s urban forests removed pollution more than Atlanta’s (1,196 t; $6.5 million) and Baltimore (499 t; $2.7 million), but pollution removal per square meter of canopy cover was similar among these cities (New York: 13.7g/m2/yr; Baltimore: 12.2 g/m2/yr; Atlanta: 10.6 g/m2/yr). These standardized pollution removal rates differ among cities according to the amount of air pollution, length of in-leaf season, precipitation, and other meteorological variables. Nowak’s work noted that large healthy trees (greater than 77 cm) annually remove about 70 times more air pollution (1.4 kg/yr) than small healthy trees (less than 8 cm in diameter) at 0.02 kg/yr.

His 2002 work matched earlier research regarding total CO2 sequestered within the US. Total carbon storage by urban trees in the coterminous United States is estimated at 700 million tons. These data correspond with previous analyses that estimated national carbon storage by urban trees as between 350 and 750 million tons and between 600 and 900 million tons. Carbon storage by urban trees nationally is only 4.4% of the estimated 15,900 million tons stored in trees in USA non-urban forest ecosystems. The estimated carbon storage by urban trees in USA is equivalent to the amount of carbon emitted from USA population in about 5.5 months based on average per capita emission rates.

The research reported that “urban forests in the north central, northeast, south central and southeast regions of the USA store and sequester the most carbon, with average carbon storage per hectare greatest in southeast, north central, northeast and Pacific northwest regions, respectively. The national average urban forest carbon storage density is 25.1 t/ha, compared with 53.5 t/ha in forest stands.”

He felt this data could be used to help assess the actual and potential role of urban forests in reducing atmospheric carbon dioxide, a dominant greenhouse gas.

Nowak’s research report stated the following:
“Air quality improvement in New York City due to pollution removal by trees during daytime of the in-leaf season averaged 0.47% for particulate matter, 0.45% for ozone, 0.43% for sulfur dioxide, 0.30% for nitrogen dioxide, and 0.002% for carbon monoxide. Air quality improves with 2 increased percent tree cover and decreased mixing-layer heights. In urban areas with 100% tree cover (i.e., contiguous forest stands), short-term improvements in air quality (one hour) from pollution removal by trees were as high as 15% for ozone, 14% for sulfur dioxide, 13% for particulate matter, 8% for nitrogen dioxide, and 0.05% for carbon monoxide.”

Meanwhile, www.plantit2020.org, has summarized recent forestry science studies in carbon sequestration related to trees, including the following:

The U.S. Forest Service estimates that all the forests in the United States combined sequestered a net of approximately 309 million tons of carbon per year from 1952 to 1992, offsetting approximately 25% of U.S. human-caused emissions of carbon during that period.

The US Forest Service also feels that large diameter; long-lived, leafy trees are more beneficial in regards to carbon sequestration. For example, they point to the fact that Atlanta’s 9 million-plus (mostly mature, broad-leafed) trees absorb about twice as much as Calgary, Canada nearly 12 million trees (many conifers).

They also noted that tree species is a strong determining factor regarding carbon sequestration, which vary by species in their rate of storing carbon, though research is still needed.
But, as a counter action, trees also vary in how many and how much harmful volatile organic compounds (VOC’s) they emit. One common example is isoprene, which produces the greenhouse gas ozone.

So, the best tree species is one that rapidly sequesters carbon but does not register high outputs of VOC’s. Long-lived trees (those living more than 50 years) are preferred by the Forest Service for carbon sequestration as dead trees rot – releasing all of the carbon that has been stored. US Forest Service recommends the following species for the United States…American basswood, dogwood, Eastern white pine, Eastern red cedar, gray birch, red maple and river birch.

Nowak does point out that the placement of trees actually has more impact that sequestration.
“The bigger impact comes from planting a tree in the proper location where it can provide cooling for buildings,” he said. “Just by preventing the added CO2 being emitted during air conditioning, trees can have four times the impact they have in sequestration.”

So, there are many functions to consider to maximize a tree’s impact on the environment, he cautioned.

Tropical Versus Temperate Zones
Another study, lead by Lawrence Livermore National Lab, indicated that trees planted closer to the equator sequester more carbon than those planted far to the North. Why this might have happened is still unclear. Some expert speculated that Southern tree species are often larger, long-lived, leafy trees compared to northern species.

Their computer models seem to confirm this observation. They built a model to determine the impact on temperatures forests have in different parts of the planet.

They focused on three key factors in their analysis:
• Forests can cool the planet by absorbing the greenhouse gas carbon dioxide during photosynthesis.
• They can also cool the planet by evaporating water to the atmosphere and increasing cloudiness; a deck of white clouds reflects incoming solar radiation straight back out into space.
• But, trees might also have a warming effect. They are dark colored, absorb sunlight and hold heat near ground level

“Our study shows that tropical forests are very beneficial to the climate because they take up carbon and increase cloudiness, which in turn helps cool the planet,” explained Dr. Bala, an author on the Livermore study.

So, the further you move from the equator, the more these gains are eroded she stated. The team’s modeling predicts trees planted in mid- and high-latitude locations could cause a net warming of a few degrees within a hundred years.

“The darkening of the surface by new forest canopies in the high-latitude boreal regions allows absorption of more sunlight that warm the surface,” Dr Baal said.

Counter Views
But, despite the general excitement over planting trees, no, literally planting forests as a solution to global warming, has hit some speed bumps recently.

In addition to the Livermore computer model concerns, two other recent papers in the scientific literature raised questions about the benefits of terrestrial carbon sinks. One paper, by Frank Keppler, Max Planck Institute, discovered that plants emit significant amounts of methane, which is a potent greenhouse gas, which traps heat much more efficiently than CO2.

Another study, by Robert Jackson, Duke University, found that plantations could reduce stream flow and increase salinization of soils to a greater extent than previously recognized. It looked at existing conversions and showed that the growing trees had larger water demands than crops or pastures “dramatically decreased stream flow within a few years of planting,” the authors wrote.

They also found that water use within existing tree plantations of all ages resulted in average stream flow reductions of 38 percent. Losses increased as the trees age, and “13 percent of streams dried up completely for at least one year,” the study said.

Overall, the tree farming used about 20 percent more rainwater, the study estimated. So, additional tree planting for carbon mitigation could have large impacts on nation’s water resources. This is ore of an issue in nations that net less than 30 percent of their total annual supplies of fresh water from rain, the authors predicted.

This has lead to experts some questioning the overall tree planting strategy, but others view this speculation as overblown.
Nowak also cautioned that urban tree management practices could diminish the net effects of urban trees on atmospheric C02. Activities used to maintain vegetation structure and health (e.g. from chain saws, trucks, chippers, etc.) emit carbon via fossil fuel combustion. Thus, too much maintenance could cause urban forest ecosystems to become net emitters of carbon unless secondary carbon reductions (e.g. energy conservation) or limiting of decomposition via long term carbon storage (e.g. wood products, landfills) can be accomplished to offset the maintenance carbon emissions

“Carbon released through tree management activities needs to be accounted for to calculate the net effect of urban forestry on atmospheric carbon dioxide,” he said.

He argues that unless there are secondary carbon reductions (e.g., energy conservation) or limiting of decomposition via long-term carbon storage (e.g., wood products, landfills), urban forests lose much of the sequestration gains. This, in turn, affects the species composition and tree maintenance activities chosen for an urban forest.

Some Conclusions
So, where does all this leave with trees and their effects on CO2 sequestration?

To maximize the net benefits of urban forestry on atmospheric carbon dioxide, Nowak wrote that urban forest managers should focus on the following:
• Planting long-lived, low-maintenance, moderate to fast-growing species that are large at maturity and matched to site conditions;
• Using maintenance activities that increase tree survival and longevity;
• Minimizing fossil-fuel use related to management and maintenance activities;
• Using wood from removed trees to delay decomposition or decrease the need for energy from fossil-fuel-based power plants (e.g., develop long term wood products; burn wood to heat residences); and
• Planting trees in energy-conserving locations.

This was summarized clearly by Greg McPherson in a Arbor Age article “Urban Tree Planting and Greenhouse Gas Reductions.”

He wrote that…”The climate benefits of trees in mid-latitude cities are not an illusion, although they certainly feel good. Reductions in atmospheric carbon dioxide are achieved directly through sequestration and indirectly through emission reductions. Still, planting trees in cities should not be touted as a panacea to global warming. It is one of many complementary bridging strategies, and it is one that can be implemented immediately. Moreover, tree planting projects provide myriad other social, environmental, and economic benefits that make communities better places to live.”

Thus, while CO2 absorption can be positive, putting the right tree in the right place remains critical to optimizing its benefits and minimizing conflicts with other aspects of the urban infrastructure.

Next part…coming soon. We will look at where trees work best, which trees might be the best, and include a long list of references on this topic. See you soon.

What Is Sustainable Horticulture?

Posted by sustainable_hort on March 24, 2010  |  No Comments

This is a quick thank you to all that have checked this blog and made so many positive comments. And more…a short view of where we are headed.

This blog was started to document, explain, revise, suggest and predict where the wide world of horticulture can honestly to create systems to grow plants that do not depend on petroleum based inputs (which at some point become scarce or at least much more expensive), but finds closed systems to supply those inputs. No one is saying it is easy, it still needs work and research, but natural systems are being identified. We just need to rethink some obvious biology, especially relating to soil, and how it has worked “sustainably” for millions of years.

Definitions are tricky…and “sustainability” is seems to be the rule in this case. There are many definitions, the majority of which tend to be bent to service those defining it. But, after reading numerous definitions, it seems to boil down creating ways to grow plants that will without harming workers or future generations later. Many include the definition of “environmental health, economic profitability, and social and economic equity.” This must mean “we must meet the needs of the present without compromising the ability of future generations to meet their own needs.” So, “stewardship” requires “maintaining or enhancing this vital resource base (soils, water and closed inputs) forever.”

Certain food and ornamental products have identified with this “sustainable” vision. More than identified, they have built businesses, created organic fertilizers and pesticides, established networks and distribution systems that are a first stage in creating a more sustainable horticulture. It might even lead to a more sustainable agriculture…a different conversation.

Even Miracle Grow, not the most organic product in the world, is now selling two soil amendment products. These miracle products, which the company promotes as containing “organic” components, promise healthy soils that “grow plants twice as large.” The company has recognized the concept, along with much of agriculture, that healthy soil is the literal and environmental foundation of sustainable horticulture, whether in farms or landscapes.

So, this blog first focuses on ornamental plant production. I am working with a wholesale grower in the wonderful Willamette Valley, Oregon, where plants like to grow. It is one of the main reasons I live here today. We are seeing if a grower of shrubs and trees can work towards a sustainable sustainability…one that works economically long term. A key phrase in this sentence is “long term.” And it may mean growing not the largest plant, but the healthiest plant. This is not just speculation, but has a background, starting with the works of Sir Alfred Howard and William Albrecht, and continuing today with the Rodale organization, the Leopold Center for Sustainable Agriculture, and ATTRA. I suggest reading New Opportunities in Sustainable Landscapes and Can Nurseries be Sustainable? on this blog, and investigating the references. Let’s keep the discussion going.

At the same time, this site will point to new uses of plants from green roofs and walls, to storm water control with green streets, to growing food on empty rooftops and in our neighborhoods. We find cities planting more trees, urban agriculture sneaking into backyards and along cities edges, plants being used to clean water and air, and cool our heat islands. This is all positive and needs to be recognized as an important environmental strategy, one that can also create jobs. Obviously, without plants, there is no food or air, there is no “us.” So, it becomes important to recognize and utilize plants at every level we can.

Finally, this discussion site will lead to the introduction and testing of organic input products here in the Northwest (with application nationally), and we will be providing some of those products through this site and with advertising support. This all works toward my focus, helping horticultural growers (both food and ornamental) move, step by step, to a sustainable future while still providing the planet with plants.

And, a main test site will be our organic produce operation, 19th Street Farms. Since the links on this template are not working right, just type in “www.19thstreetfarms.com/blog/” to get to the site. I will use this blog for other content, but the site will busy in summer. It is also our CAS/Farmers Market site where we are continually talking with our customers. So look under specific categories for your favorite topic.

MORE COMING SOON…

Pest Invasion Tests Sustainable Strategies

Posted by sustainable_hort on March 21, 2010  |  No Comments

Sustainability requires a careful, optimized use of a farm’s natural systems. Healthy soil, right plants in the right places, IPM strategies and diversity are all used in successful farms. It can and has worked.

But, add an outside/alien invasive force…plant, disease or pest…and that natural system is taxed and cannot respond initially. Response is possible, but it would take at least years, if not decades.

So, the story rapidly developing around the Spotted Winged Drosophila (SWD) deserved the Portland Oregonian’s huge two-word headline…”CROP KILLER.” You may have read or heard about it. This invasive, Asian pest is causing near panic on the West Coast and particularly here in the berry and fruit production areas of Oregon. Florida has also found the pest. Just type the pest name into your search engine to find numerous sites describing and discussing the SWD.

It first appeared last summer and devastated some berry and fruit crops with its “voracious” appetite for ripening fruit. Most flies prefer over ripe or damaged fruit, not ripening ones. The damage destroys the fruit with frightening speed. OSU and other researchers have jumped in. There is and will be an interesting story as scientists, extension and growers race to find some control strategy. It is especially difficult since wild blackberries are common around the edges of the rich agricultural areas, a perfect host plant for the SWD to live and thrive on. Add to this the variety of hosts within any urban environment, many of which are not treated or sprayed…this is a serious test.

What is the test? Well, more precisely, what are the tests?

First, can the agricultural/governmental infrastructure organize an effective response? Do they have resources to bring together an educated, scientific team from various inter-related fields? As a community, or state, we have slowing been strangling our agricultural depth at places such as OSU, ODA, local and regional extension offices. It is a slow death by many cuts. Again, will we still have a coordinated army of specialists to deal with SWD?

Secondly, will the ODA, dealing with other states, be able to keep Oregon’s myriad of horticulture crops moving, both nationally and internationally? It is difficult enough to battle an invasive insect when the potential damage is more limited. But, this pest attacks, from the various descriptions, across the range of berries and fruit. I am trying to find out if they like tomatoes. As a grower, this would change my tried and true systems.

Which leads to a third question…what do the organic growers do?
Conventional growers have a list of weapons that will work. But, it still adds to their projected costs which with most crops would impact bottom lines. Organic growers do not know enough yet to identify even a control possibility. They need to know if “fruit” might later include not only tomatoes, but many varieties…peppers, eggplant, squash. Any organic option will require many applications and this pest is prolific…10 generations a summer, over 100 eggs per female…you do the numbers.

Once all the crops in danger are indentified, then strategies can be developed. In some cases, I may go for a literal cover strategy…closed hoop houses, possibly enclosing with row crop floating covers. But this is a very tiny fly, so there is question what will keep them away?

Meanwhile, this type of challenge seems to support the idea of more diversity in the growing of many crops; and more smaller, local producers serving surrounding communities. This lessens the opportunity for pests moving into vital food chains. I mean, Oregon’s blueberry fields and peach orchards must have looked like SWD nirvana…”here’s a neighborhood we can settle in.”

At this point it’s more questions and a scramble for information. Stay tuned.

Green Streets/Bioswales/Rain Gardens

Posted by sustainable_hort on March 16, 2010  |  No Comments

After at least a century of hard engineering solutions for urban rain/storm water run-off, communities are turning more and more to using a plant-based technology that mimics nature’s wetlands and ponds.

Portland, Oregon, has played a leading role in supporting and developing this concept, with successful demonstration projects now helping control negative storm water events that included flooding and the overflow of sewage into local rivers.

Just holding back the flow of a major rain event is enough justification for continuing the development of green streets, or rain gardens. When the cost of “hard” infrastructure is considered, these plant-based technologies may be the perfect “green” technology to receive early installation.

All these variations…green streets and rain gardens…are built on the concept of bioswales. So, much of the information is based on bioswale research and the success of earlier projects.

A Decade of Development
One of the first scientifically designed, large-scale bioswales was built in 1996 for Willamette River Park in Portland, Oregon. This bioswale, at a total of 2330 lineal feet, was designed to capture pollutant runoff and prevent it from entering the Willamette River. Silt capture was improved by adding intermittent check dams. The dams reduced suspended solids entering the river system by 50 per cent.

Another example of a large, designed bioswale is at the Carneros Business Park, in Sonoma County, California. In 1997 the California Department of Fish and Game and County of Sonoma, working with an environmental design team, created a detailed design that took the surface runoff from the park’s large parking area. The runoff came from the building’s roof and parking lots. There was also an overland flow from properties located north of the project site. A two-mile bioswale was built to reduce runoff contaminants from entering Sonoma Creek. The grass-lined bioswale channel has an almost linear construction, with a down slope gradient of four percent and six percent cross-slope gradient.

Another early project, completed in 2001, is Seattle’s pilot Street Edge Alternatives Project (SEA Streets). Its drainage designs closely mimics the natural landscape compared to traditional piped systems. Impervious surfaces were reduced, now with 11 percent less than a traditional street while providing improved surface detention in swales. SEA also added over 100 evergreen trees and 1100 shrubs. Two years of monitoring show that SEA Street reduced the total volume of storm water leaving the street by 99 percent.

Meanwhile, back in Portland, the Bureau of Environmental Services has created a “green streets” program. In one project, the city retrofitted SW 12th Avenue, near Portland State University, to collect runoff from 8,000 sq ft and running it into a series of four planters. Up to 6 inches of water can be collected in each planter, then the water overflows down the street to the next planter. In 2006, the project won a General Design Award of Honor from the American Society of Landscape Architects.

There are even companies now that focus on the design, construction and promotion of rain gardens and related products, such as rain barrels. This is another great example of how the low-tech use of plants can solve serious environmental problems, instead of billion dollar “hard” solutions such as Portland’s two massive pipe system projects now under construction.

Definitions
But, despite many similarities, there are some differences between the bioswale variations.

A swale is a low tract of land, that usually exists in a moist or marshy situation and can be a natural landscape feature or one specifically built for environmental reasons. The later is often an open drain system is that manages water runoff.

Bioswales are landscape elements designed and built to remove silt and pollution from surface runoff water. These “swaled” drainage courses are, in a sense, gently sloped ditches that contain plants, compost and/or riprap. The sloped sides are usually less than six percent slope.

As water flows though the typically wide and shallow ditch, so the water spends enough time in the swale, to help trap of silt and pollutants, a bioswale can have a meandering or almost straight channel alignment, based on the lie of the land where it is built.

Bioswales are often built around parking lots due to auto pollution. Potential harmful compound end up being collected on the paving and then flushed by rain. The bioswale, acts as a biofilter, and surrounds the parking lot. As the runoff enters the bioswale, it is cleaned before entering a watershed or storm sewer.
The bioswales can also contain biological factors also contribute to the breakdown of certain pollutants.
Bio-retention ponds, commonly called “rain gardens,” are landscape features that help control rainwater runoff. The runoff comes from roofs, driveways, walkways, compacted lawn areas and other impervious urban surfaces, and cause problems, especially during the large storm events. Structures, low-lying depressions and other landscape constructions that slow and deter running water allow heavy rains to be absorbed into the soil. This prevents the urban situation where the rains flow into storm drains and cause secondary environmental problems. Or it becomes surface water that causes erosion, water pollution, flooding, and diminished groundwater. Some studies claim this can reduce the pollution reaching creeks and streams by up to 30 percent.

Rain garden plants also return water vapor into the atmosphere through the transpiration.

Thus, rain gardens are essentially all landscape features that capture, channel, and divert natural rain and snow that falls on a property. This diverted water may also find other uses, such as stored water returned as irrigation. If designed correctly, an entire landscape or garden can become a rain garden. Individual elements act as components or small-scale rain gardens.

Meanwhile, green streets use small-scale, vegetated bioswales, built along streets that again help control storm water events. These constructed elements create on-site infiltration, while providing attractive streetscapes. They also improve a neighborhood’s livability by adding park-like elements that serve as urban greenways. As mentioned earlier, the City of Portland has officially incorporated green street facilities into all its development, redevelopment or enhancement projects. Besides treating and infiltrating storm water, these projects can also increase tree shade canopy and support native habitat all in the parkways and medians.

It is important to note that these man-made water-control landscapes’ success depends on an adequate “infiltration rate.” This measures, in inches or millimeters per hour, the rate a particular soil absorbs rainfall or irrigation. As the soil becomes saturated, the infiltration rate decreases. When the precipitation rate exceeds the infiltration rate leads to “runoff.” So, the correct soils are also crucial to the overall functioning of all these bioswale variations.

In addition, most of these bioswale-based, water control landscapes are using at least some, if not all, native or related plant choices. This leads to both environmental and cost advantages.

Why Bioswales…Benefits of Water Control Landscapes
These wetland variations, working like their natural versions, have several key benefits that will increase their use as bioswale technology becomes adopted as an effective construction element in urban settings.

• Reduced expense for storm water management facilities
In many locations, natural landscaping, like bioswales or rain gardens, can handle and control storm and flood waters. This, in turn, can reduce the need for expensive, “highly engineered” pipes systems and detention facilities. More and more real world projects are showing that drainage swales can cost much less to install than storm sewers.

“Sustainable innovations can actually reduce costs,” explained landscape architect Paul Morris, speaking at an annual meeting of Oregon Landscape Contractor Association. Morris works on planning and sustainable issues for Cherokee Investment Services, Inc., an international development firm that has long recognized the many benefits of incorporating sustainable technologies into their projects.

He said these include storm water run-off (largest environmental problem in US) control using bioswales, rain gardens, green roofs, and capturing the water on site can be less expensive to construct than traditional solutions.

When curbs and gutters are eliminated and curbs are slotted, there can be substantial construction savings. When natural drainage measures increase infiltration of storm water into the local soil, runoff volume is reduced while the need for downstream conveyance and detention structures is reduced.

Other projects found that detention basins, designed with natural landscaping to resemble wetlands or natural lake systems, also reduce costs over conventional basins. These “natural” landscapes eliminate the need for expensive riprap stabilization and low flow channels paved with concrete. Natural vegetation in detention basin bottoms and on side slopes is less costly to maintain than conventional turf landscaping (see next section), and is a more reliable soil stabilizer.

• Removing Contaminants
As was indicated in the definition of a bioswale, one reason to slow water down is so it can react with the nearby plants, roots and soil. This has documented several benefits.

First, these plant-based technologies can help control several classes of water pollutants, including silt, inorganic contaminants, organic chemicals and pathogens. This falls under the definition (according to Wikipedia) of “biofiltration.” It is defined as “a pollution control technique using living material to capture and biologically degrade process pollutants.” These process include cleaning waste water, capture chemicals that are potentially harmful, micro biotic oxidation of contaminants in air, or collecting silt from surface water runoff.

This is similar to “bioremediation,” which is defined as “any process that uses microorganisms, fungi, green plants or their enzymes to return the natural environment altered by contaminants to its original condition.” Bioremediation may be employed to attack specific soil contaminants, such as degradation of chlorinated hydrocarbons by bacteria. An example of a more general approach is the cleanup of oil spills by the addition of nitrate and/or sulfate fertilizers to facilitate the decomposition of crude oil by indigenous or exogenous bacteria. (Wikipedia)

With silt, the bioswale or rain garden’s effect is to slow the moving water, reducing turbidity, and allowing the small soil particles to drop out of the water. Thus, the soil is returned to a place where it is beneficial instead of traveling downstream to become a problem.

Meanwhile, inorganic compounds, such as metallic compounds like lead, chromium, cadmium and other heavy metals, are common pollutants, especially in areas of heavy auto use. Lead, from automotive residue (e.g. surface spillage of leaded gasoline) is the most common example.

Other common inorganic polluting compounds include phosphates and nitrates, whose main source is excess fertilization. This often causes “eutrophication,” defined as “an increase in chemical nutrients — compounds containing nitrogen or phosphorus — in an ecosystem from the release of sewage effluent, urban storm water run-off, and run-off carrying excess fertilizers into natural waters. It may occur on land or in water.

However, the term is often used to describe the resultant increase, and thus excessive, plant growth and decay in aquatic environments. This results in a lack of oxygen and results in severe reductions in water quality, fish, and other animal populations, disrupting normal functioning of the ecosystem, In aquatic environments, this enhanced growth creates choking aquatic vegetation or phytoplankton, often known as “algal blooms.”

Meanwhile, common pesticides, frequently over-used in agricultural and urban landscaping, are also seriously detrimental organic chemicals. They can actually poison some organisms and often seriously disturb aquatic ecosystems.

Finally, there are human pathogens that usually come from animal waste in surface runoff water. In just the past few years, it has lead to a several serious diseases in humans, with outbreaks coming from spinach and peanut butter.

Less recognized, but still serious, are comparable diseases that have affected aquatic organisms.

• Reduced costs of landscape installation and maintenance
Studies have shown that these “bioremediation” technologies are less expensive than the some other landscaping options. For instance, conventional rolled-sod, turf lawns can have installation costs exceeding $12,000 per acre, while planting grass seeds may cost $4,000 to $8,000 per acre. But, seeding native prairie grasses and forbs costs only $2,000 to $4,000 per acre.
Several publications noted that planting native plants plugs increases installation costs significantly but does give plants a “head start” if desired.

Another plus is that sponsors and volunteers can help control native plant installation costs. Sponsors can even sometimes be a public or private entity with plant propagating capabilities. Volunteers can be recruited to install and maintain native landscapes.

And, natural landscaping just cost less to maintain. Over the first ten years, the combined costs of installation and maintenance for natural landscape can be as little as one fifth of the costs for conventional landscape maintenance. Many projects use a range of native plants already adapted to the region’s soil conditions and climate, including summer heat and drought. Natural landscaping lowers many normal costs including labor, water, fertilizer, herbicides, insecticides, and fungicides, replanting annual flowers, and mowing. In drier climates, natural landscaping lowers the high irrigation costs.

The reduced use of lawn maintenance equipment lowers gas use, an additional benefit. Natural landscapes require simple maintenance, usually just annual mowing or burning, and some weed removal (mostly in the few years after installation)

This, like green roofs and green walls, is becoming a new market for both growers and landscape contractors. With Portland leading the way in this area, it will be one more topic this blog will continue to follow. If you are interested in more details, go to www.portlandonline.com/BES/, click on “Stormwater Solutions” under Library.

Watch for the upcoming post that discusses and provides references on the plant material being used in this newest version of sustainable horticulture.

Worm Culture…Helping Save the Planet

Posted by sustainable_hort on March 9, 2010  |  No Comments

OK…I admit the headline is a bit overblown…but I have been encouraged by recent increased activity around using worms to recycle bio-materials, mainly food waste.

I have personally followed the vermiculture movement for decades, since these hard working organisms both help create healthier soils and are indicative of them. My static compost bins have long since turned into worm bins, and more than handle all our food waste. I have even been testing commercial worm castings in a container plant production system as part of an organic mix.

Equally important is the idea that vermiculture might be an answer to one of our concerns…getting rid of food waste. Most of it now travels to a landfill site to be buried with all the other “garbage.” But, is it really “garbage” or “waste?” Current vermiculture systems can take the mountains of food waste and turn them into worm castings (poop), a rich and biologically active soil amendment.

While many authors have praised worm castings as improving soil health, there has been limited research into how they affect plant growth. But, a recent study at North Carolina showed that adding “vermicompost” to the container mix for Hibiscus plants showed dramatically improved growth with a 20% compost mixture. For more information, contact Michelle McGinnis at michelle_mcginnis@ncse.edu.

I have seen similar results in my testing.

If you don’t believe there is a food waste issue, read the book “Waste” by Tristram Stuart. This covers the food waste issue world wide, with many depressing statistics on how much food gets thrown out. In fact, studies show that “around half of all food in the US is wasted!” And, this is a trend that has tended to increase over the past few decades. So, the raw material is there…we just need systems to collect, process and distribute this potential soil builder. It would solve several problems at once.

In fact, here in Portland, there is a neighborhood activist, Randy White, who is trying to organize neighborhoods into worm composting centers. (He can be contacted through his website “Bright Neighborhood” at www.brightneighbor.com.) Those in the specific area would invest $250 and contribute all their food waste to their local worm farm. The wastes would turn into soil food and given to those that supplied the raw materials…recycling within the neighborhood

If you don’t know much about this, a good place to start is with the website www.vermiculturemanual.com/en/index.html. It lists links to courses, and contains lots of basic information. Or, you can get much of what you need free with the “Manual of On-Farm Vermicomposting and Vermiculture” by Glenn Munroe (Organic Agriculture Centre of Canada). This PDF publication is available online at www.agbio.ca/DOCs/Vermiculture_FarmersManual_gm.pdf.

Other books include “In Their Own Words: Interviews With Vermiculture Experts” edited by Peter Bogdanov; and “Beyond Compost: Converting Organic Waste Beyond Compost Using Worms” by Tom Wilkinson. They are available through online sites…just type in “books on vermiculture” to find them.

This site will follow this activity, both locally here in Portland, and internationally. It is just one of what I like to call a “middle-of-the-road-radical” solution to a problem. One where it seems everyone, including the public in general, gains something positive.

Soil Health and Organic Fertilizers

Posted by sustainable_hort on February 12, 2010  |  No Comments

Below is another response to an online post. The basic question was “what are good organic fertilizers” and some responses questioned whether they work or not. These are my quick thoughts…the books listed below apply to sustainable horticulture in many ways.

First, I am not so sure that “plants don’t know the difference” between petroleum-based and organic nutrition. A healthy, vibrant soil community provides the nutrition, and often the protection, plants need to be in prime health. This does equal using “dry weight comparisons” as the measure of health. Plants can grow too fast, too much nitrogen actually enhances disease and pest issues, and NPK is not the only factor is consider in plant health.

There are some key works that support this idea of “healthy soils equals healthier plants,” some pre-World War II. I would suggest reading Health & the Soil and An Agricultural Testament by Sir Albert Howard, the works of Dr. William A. Albrecht, Science in Agriculture by Arden Andersen, and Ask The Plant by Charles Walters and Esper K Chandler. A more recent work, Healthy Crops, A New Agricultural Revolution, by Franci Chaboussou, examines 75 years of research in this area. It provides a fairly convincing argument against current application practices with nitrogen fertilizers and many pesticides and herbicides, since they can be shown to increase pest issues. Even recent popular works, such as Teaming with Microbes by Jeff Lowenfels and Wayne Lewis, are identifying a simpler approach to soils, what is in some ways, an older agriculture.

Secondly, I would agree there tends to be a lot of hype around these products…just look at the compost tea issue. Several decades ago, some organic products were being sold as “magic,” which over-shadowed similar products long-term benefits.

But, I went back to Oregon State University decades ago to study composting, got a horticulture degree, and ended up in the Oregon nursery industry, which grows many of its products in relatively artificial systems. I have tested the options, learned to grow most plants without excessive N, using organic pest controls (though few were even required). There is getting to be more research into soil health, we have major ag schools adding organic production to their curriculum, and the consumer is asking more questions. Meanwhile, my organic farm seems to be flourishing and early tests in a local ornamental nursery show “organic” shrubs and trees are not only possible, but may be even cost effective. These products work, you can achieve equal production, and many are sustainable…often taking consumer waste and turning it into plant food. These are natural cycles we should continue to tap.

Trees Saving the Planet?

Posted by sustainable_hort on February 1, 2010  |  No Comments

The New York Times is reporting that a new research report, being published in today’s issue of The Proceedings of the National Academy of Sciences, indicates that trees are growing faster, perhaps in response to the atmosphere’s added carbon dioxide. (http://www.nytimes.com/2010/02/02/science/earth/02trees.html)
This relates to my last three posts that discussed the increasing role plants will play in solving climate change issues. This plant and planetary reaction seems to confirm some of the Gaia theories of James Lovelock, see site: (http://en.wikipedia.org/wiki/Gaia_hypothesis).
So, does this mean that the cooler temperate regions might actually see increased growth of not only the natural vegetation, but agricultural crops as well? There are already early olive ventures in the Willamette Valley of Oregon, moving up from California. Will Oregon start growing oranges next? Or maybe avocados!
Follow this site as we investigate, synthesize and report on the new “plant technologies,” including green roofs, green walls, bioswales, higher respirating plant varieties, plant site placement, etc.