Wednesday, November 25, 2009
Wednesday, October 14, 2009
His Power Point presentation, 'Invasive Species 101: A Primer for Master Gardeners' is posted online for all.
Here, you can view a list of species which have been classified as noxious weeds in Oregon (i.e. they are invasive). The savvy or long-time gardening may recognize that many of these beautiful plants were once popular among gardeners. These include Bachelor's Button, Spurge Laurel, and Old Man's Beard. Now, instead of being the propagators of invasive plants, gardeners are valued partners in the fight against invasive species.
Why should we be worried about invasive species?
** Invasive species often outcompete native plants and animals, which results in a loss of native biodiversity. If you've ever seen native riparian areas become overtaken by Japanese Knotweed, it is a loss of native beauty and biodiversity to mourn. Or, a drive up to Portland along I-5 provides a glimpse into how English Ivy can overtake forest fragments.
** Invasive species can be costly! For example, leafy spurge is abundant in the Oregon counties of Klamath, Grant and Cook. Where is it present, it can reduce the carrying capacity for cattle by 50-75%! Scotch Broom infestations in Western Oregon are estimated to result in an economic loss of $47 million dollars, due to a reduction or loss of timber production.
Educate yourself about invasive plants, and you are in a prime position to educate clients about the potentially negative impacts of invasive species on our environment and our economy.
When a client comes into the Plant Clinic, or calls the gardening hotline and asks 'What is this plant?' - you have an educational opportunity.
First - inform the client that the plant is designated as a noxious weed by the Oregon Department of Agriculture.
Second - give the client who can't part with the beautiful Butterfly Bush (or another attractive invasive) options for control. Deadhead invasive ornamentals faithfully before they go to seed. Use root barriers to contain an invasive in your yard. Dispose of invasive plant materials (clippings, pulled plants, flowers, ANYTHING) by bagging them in a sealed plastic bag and placing them in the trash. Where municipalities allow, invasive plant materials may be burned.
Third - become familiar with the latest control options for a particular plant. Because Japanese Knotweed is able to grow from even the tiniest of stem fragments - mechanical cutting and removal is not an effective means to control this plant. Leave a small stem fragment (about the size of your thumb) on the ground, and the plant may come back in force. Instead, herbicide applications are much more effective. Of course, whenever using any type of pesticide, including herbicides, follow all label directions and check the PNW Weed book to make sure that a particular herbicide is registered for use by homeowners.
Finally - don't propagate the spread of invasive plants. Don't share a plant with your friends unless you know it is non-invasive. Plant native plants and non-invasive plants in your garden. Check for potential 'hitchhikers' on plants you purchase from a local nursery or at a plant sale. Become educated about the primary invasive plant species in your area - as well as species that are a potential threat to your area, but have yet to be found (hello, garlic mustard!). If you find an invasive plant that is new to your area, report it to the Oregon Invasive Species Hotline.
Monday, June 8, 2009
The 26th annual Gardeners Mini-College will be held from August 5-8, 2009 at the CH2M Alumni Center on the OSU campus in Corvallis, Oregon. Mini-College is an educational event put on by the OSU Master Gardener Program and the Oregon Master Gardener Association (OMGA).
The theme for this year's Mini-College is “Backyard Food Solutions: Local. Sustainable. Secure.” Choose from over 30 talks, tours and workshops, on a variety of topics, including:
cover cropping your vegetable garden, home winemaking, backyard chickens, organic vegetable gardening, heavy metals in garden soils, home orchards, backyard wine and table grapes, composting, season extenders, making teas from garden herbs, dealing with deer and other mammals in the home garden, an in-depth look at garden fertilizers, etc.
You do NOT have to be a current OSU Master Gardener in order to attend Mini-College. This conference is open to all! This event is the Statewide Master Gardener Conference for Oregon gardeners. Please join us!
Online registration is open until July 15, 2009. Early bird registration discount ends on June 26, 3009.
Wednesday, April 1, 2009
Below, for those who are interested, is the testimony that I will deliver on April 2, 2009.
Monday, March 30, 2009
I will return to blogging on the science underlying gardening and issues related to gardening soon. Currently, I am writing a short piece on compost teas.
In the meantime, I wanted to draw attention to Organic Gardening Certificate Program, which is currently taught in the Portland Metro area. This 57-hour training was created by OSU Extension, Oregon Tilth, and other program partners to support the groundswell of interest in organic gardening, ecological landscaping, and food security in the Portland metro area.
The 2008 Organic Gardening Certificate Program (OGCP) is the focus of the cover story for the spring Edible Portland magazine in both the print and online versions.
Check it out at http://edibleportland.com/content/currentissue/ and click on the “Dig in” link and look for the article entitled “First Class.”
Saturday, March 28, 2009
In a recent American Entomologist article, Anna wrote that the target audience for the podcast is primarily kids and young adults. One of the goals of InsectaPodCast is to get kids excited about the field of entomology. I'm MUCH older than the target audience (by about 30 years), yet I found myself LOVING the segments. The episode about insect collections is thus far my favorite, perhaps because of my own mixed feelings about collecting insects that I love (i.e. killing insects that I love), for scientific study.
Check it out, and perhaps subscribe to the RSS feed, if you like what you hear.
Thursday, March 12, 2009
A 1995 study found the Yard Gard (sic) Ultrasonic Yard Protector to be ineffective at deterring deer from feeding on apples in two yards with a history of deer damage. Control (no Yard Gard device) and treatment (Yard Gard device present and turned on) feeding stations were established at each yard. Twenty apples were placed at each feeding station. Feeding stations were restocked for the duration of the study.
Deer consumed 96% of the 380 total apples at the control stations (no Yard Gard) and 98.9% of the 380 total apples at the experimental stations (Yard Gard device present and turned on). Behavioral observations suggest that the deer were alert or nervous when the Yard Gard device was 'on', but this behavior did not translate into reduced deer damage.
The scat (poop) and tracks of several other vertebrates were found near the feeding stations. These include squirrels, crows and turkeys.
The bottom line for the home gardener: the ultrasonic deer deterrents are not likely to reduce deer damage to your garden.
Tuesday, March 10, 2009
First, let me define organic versus conventional farming methods. Although the USDA lists a lengthy definition and regulatory text for organic production systems, I think that it will be more useful to distill down the definition for this blog. Organic farmers work to build and maintain the organic matter in their soils and the natural pest control agents in and near their fields (i.e. predators and parasitoids). Organic farming systems tend to be more diverse (in both their crops and associated organisms) than do conventional systems. Cultural, physical and biological controls of pests are emphasized over chemical controls. External inputs of pesticides and fertilizers are reduced. When pesticides and fertilizers are used, organic forms of these products are used. Synthetic forms of these products are not allowed in organic production systems.
Conventional farming systems, by comparison, do not focus on soil management, biodiversity within their fields and cultural or physical controls of pests. Biological control of pests is often disrupted or difficult due to the use of pesticides (which may be organically derived or synthetically manufactured).
Organic farm production often occurs at a smaller scale, and requires more labor, than does a conventional farm. This is why organic produce can be more expensive than conventional produce.
In fact, a 1998 study of the cost difference between organic and conventional produce in Tucson, AZ found that red delicious apples were 44% more expensive than conventionally grown applies. Similar results were found for broccoli (+76%), carrots (+78%), leaf lettuce (+92%), and tomatoes (+62%). [Gary D. Thompson and Julia Kidwell. 1998. Explaining the Choice of Organic Produce: Cosmetic Defects, Prices, and Consumer Preferences American Journal of Agricultural Economics, Vol. 80: 277-287.]
Unfortunately, I could not find more recent numbers in the peer-reviewed literature. OSU Master Gardeners – would you care to help me out with a quick and easy research project? If so, contact me via this blog.
What about the nutritional content of organic versus conventionally-produced foods? A 2003 study by Asami and colleagues looked at the total phenolic content of marionberries, strawberries and corn that were produced by organic, ‘sustainable’ and conventional methods. In this study, organic fields were managed to adhere to USDA organic production standards. Sustainable fields were managed to ‘meet the needs of consumers without compromising the ability of future generations to meet their own needs’. Information is presented on the fertilization regime of the sustainable fields (synthetic fertilizers were used), and on the pesticides used (none in one field and herbicides in a second field) but additional information on sustainable management practices were not presented in this paper.
The authors looked at total phenolic content of these plants, because polyphenols, in particular, are known to have anti-oxidant properties. For marionberries and corn, higher levels of total phenolics were found in organically and sustainably produced, relative to marionberries and corn from conventionally managed fields. Sustainably produced strawberries had higher total phenolics, relative to conventionally produced strawberries (the authors did not include organically grown strawberries in their study) – but only when strawberries were frozen, and not when they were freeze-dried or air-dried. [Asami, D. K., Hong, Y-J., Barrett, D. M. & Mitchell, A. E. (2003). Comparison of the total phenolic and ascorbic acid content of freeze-dried and air-dried marionberry, strawberry and corn grown using conventional, organic and sustainable agricultural practices. J. Agric. Food Chem. 51(5):1237-1241.]
Two recent review papers found similar results (Zhao et al. 2006, Benbrook 2009). Nutrient density and secondary plant metabolites (many of which are known to have anti-oxidant properties) tended to be higher in organically-produced foods than in conventionally grown foods.
Why might organically grown foods have more nutrients and anti-oxidants that conventionally grown foods?
First, organically-grown foods are often grown in soils with abundant and balanced micro- and macro-nutrients. This is because organic food production emphasises the accumulation and retention of organic material in the soil. This may translate into produce that contains a more balanced array of vitamins and minerals.
Second, insects may feed upon organically-grown crops more often than they damage conventionally grown crops. This may be due to differences in pesticide use in organically versus conventionally-managed fields. When insects feed upon a plant, they can induce or trigger the plant’s chemical defenses against herbivory. These chemical defenses can include polyphenols – which are known to have antioxidant properties.
What does this mean for the home gardener?
Managing your soil to encourage and maintain a high level of organic matter, and minimizing or removing pesticid use in your vegetable garden can yield multiple benefits. First, these management practices are generally more environmentally friendly than are the repeated and unncessary use of synthetic fertilizers and pesticides in the home garden. Second, these management practices may result in you and your family enjoying fruits and vegetables that contain more vitamins, minerals and antioxidents than those that come from vegetable gardens that are managed without regard to soil health or the non-target effects of pesticides.
Monday, February 23, 2009
Now, a group of Korean researchers may have identified a mechanism for these positive benefits of indoor plants. (Kwang et al. 2008. Efficiency of Volatile Formaldehyde Removal by Indoor Plants: Contribution of Aerial Plant Parts versus the Root Zone. Horticultural Science 133: 479-627.)
Researchers from Korea's National Horticultural Research Institute examined the ability of Ficus benjamina and Fatsia japonica to absorb formaldehyde from the air. To study this, the researchers pumped formaldehyde into a container that held one of the two plants, or into a container that was empty. On average, containers with plants removed 80% of the formaldehyde from the air in only 4 hours. Containers without plants lost only 7% of the formaldehyde in 5 hours. Plant leaves reduced more formaldehyde during the day, while roots of reduced more formaldehyde at night. This suggests that formaldehyde is taken in through plant stomates during the day, when rates of photosynthesis are highest. The night removal of formaldehyde by the root zone suggests that soil microbes play an important role in formaldehyde removal.
Formaldehyde is a common household VOC (volatile organic compound) that is known to have negative effects on human health. In fact, VOC's, including formaldehyde, have been linked to 'sick building syndrome'.
What is the bottom line for the home gardener, or the party guest who is looking for a suitable hostess gift? Indoor plants will reap multiple benefits, not the least of which is better air quality, for the gardener or the gift recipient.
Wednesday, February 18, 2009
Burghardt and colleagues measured the diversity of birds and caterpillars (which are, of course, the larval or juvenille form of butterflies) in 12 suburban yards in Pennsylvania. Six yards were landscaped almost exclusively with native plants (43% native and 6% exotic plant cover), and the other six were landscaped with exotic shrubs and groundcovers (although, native trees were present on these properties; 18% native and 26% exotic plant cover).
The abundance of caterpillars (the larvae of butterflies and moths) was 4 times greater on the 'native sites', relative to the 'exotic' sites. In addition, the number of different species represented by these caterpillars was 3 times greater on the 'native' sites, relative to the 'exotic' sites. Approximately 19 species of bird were found at the native sites, compared to 11 species at the 'exotic' sites. Mean abundance of birds at the 'native' sites was 17, compared to 11 birds at the 'exotic' sites.
Why do yards landscaped with native plants contain a greater abundance and diversity of birds and butterfly larvae? Burghardt and colleagues hypothesize that greater food availability for caterpillars at 'native' sites creates greater food availability for birds at such sites. Because many plant feeding insects can not feed exotic plants, and because many birds rely upon insect protein (rather than seed protein) to rear their young, planting native plants seems to cascade up the food chain - fostering an increase in abundance and diversity of plant feeding insects, which in turn fosters an increase in abundance and diversity of insect-feeding birds.
What does this mean for the home gardener? A yard landscaped with native plants can be beautiful, may reduce your fertilizer and water use (if you zone your plants accordingly, and if the natives are adapted to your soils), and can help to conserve biodiversity in your area.
For more on native plant gardening, please visit the Eco-Gardening website created by OSU Extension's Linda McMahan.
Monday, February 16, 2009
Topping this last has to be the first President of the United States of America (one of my personal heros, for the way that he so selflessly stepped away from power, despite the protests of many compatriots). George Washington farmed at his Mount Vernon estate, where he overcame the poor soils by practicing a relatively novel plan of crop rotations. When he abandoned tobacco farming in about 1765, he switched to wheat and at least 60 other field crops.
Of course, we can not forget Thomas Jefferson, who grew more than 170 varieties of fruit and 330 varieties of vegetables in the gardens at his Monticello estate, and had a special interest in the pea plant. In fact, Jefferson cultivated over 22 varieties of pea. Following the expedition of Lewis and Clark, Jefferson developed a curiosity about the plants of North America, and how they could be used for practical purposes.
In 1825 John Quincy Adams developed the first flower garden at the White House. Adams also planted herbs and vegetables at the White House, as well as ornamental trees.
In 1835, Andrew Jackson established a White House orangery (a type of greenhouse) where tropical trees and flowers could be grown. Jackson also added the Jackson magnolia to the White House grounds. The orangery was demolished in 1857. In 1878, Rutherford B. Hayes started the tradition of planting commemorative trees for Presidential Inaugurations - a tradition that persists today.
As for First Ladies - Eleanor Roosevelt famously began the Victory Garden movement in 1943, when she planted a vegetable garden on the lawn of the White House and Lady Bird Johnson has long been associated with efforts to conserve native plants.
Today, Roger Doiron of Kitchen Gardeners International is helping to lead a campaign to re-establish a Victory Garden on the lawn of the White House.
Happy President's Day!
Thursday, January 1, 2009
Given that my thoughts have turned to how much carbon I emit when I drive to teach, I thought I would blog about how much carbon we can sequester or emit via our lawn care practices.
In 2002, an article in Agronomy Journal (94:930-935) by Qian and Follett attracted much attention from scientists and industry professsionals, alike. Briefly, Qian and Follett measured the soil organic matter (abbreviated, hereafter, as SOM) in 15 golf courses that ranged in age from 1.5 to 45 years old (as of the year 2000). Because carbon is a key component of SOM (approximately 57% of soil organic matter is carbon, by weight), scientists have long used measures of SOM as a proxy for the amount of carbon sequestered by soils. Qian and Follett found that SOM increased with the age of the golf course, and that SOM continued to increase until about 31 years in fairways and 45 years in putting greens. Furthermore, Qian and Follet found that previous land use influenced total SOM. Agricultural fields that were converted into golf courses had lower SOM than golf courses that were converted from native grasslands. This last finding can potentially be explained by another study, conducted by Khan and colleagues (see below).
However, a paper presented at a recent meeting of the American Geophysical Union questions the overall utility of turf to moderate the emission of greenhouse gasses. Amy Townsend Small measured SOM in 4 parks in Irvine, California. The parks were established between 4 and 34 years ago. While Townsend Small found that older parks had more SOM, she also found that older parks emitted more nitrous oxide, which is a potent greenhouse gas. Although the precise cause of this relationship is not known, Townsend Small hypothesizes that a build up of nitrogen in the soils, as a result of repeated fertilizer applications, may contribute to increased nitrous oxide emissions.
In addition, a recent paper published in the Journal of Environmental Quality by Khan and colleagues reports that long term application of nitrogen fertilizers to corn fields decreases SOM. Khan and colleagues suggest that excessive nitrogen applications increases the decomposition of dead organic matter and SOM by soil bacteria. This is perhaps why Qian and Follet found that golf courses converted from agricultural fields had less SOM than golf courses convereted from native grasslands - the native grasslands were not subject to repeated fertilizer applications.
Taken together, what does all of this mean for you, the gardener? Here are the take home points:
1) Plants in general, including turf grasses in lawns, sequester carbon and may help mitigate carbon emissions and global climate change.
2) The benefits we all may gain, from increased SOM and carbon sequestration, can be nullified if we use fertilizers excessively. Excess fertilizer may volatize into nitrous oxide (a greenhouse gas) or may accelerate the decomposition of organic matter in the soil. Neither of these is good for helping to slow global climate change.
3) Khan and colleagues suggest that farmers should get a soil test before applying fertilizers to their fields. Doing so will lessen the likelihood that fertilizers are applied excessively. I suggest the same for you and I, dear gardener. Having your soil tested prior to applying fertilizers will help to ensure that we apply only what is needed, and only when soil nutrients are truly depleted.