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Home  > Question of the Week

Question of the Week

Permalink How can I control poison ivy without using chemical herbicides?

Answer: Controlling poison ivy is a difficult task, and it may take a long period of time to get a handle on it. Here are a few options for controlling poison ivy without the use of chemical herbicides.

1. Control poison ivy by constantly mowing or cutting young shoots until the plants die. This will tend to exhaust the roots and the plants will die over time. Another way is to dig up the plant roots and all. The roots will resprout if left on the soil surface.

2. Grazing goats or sheep can feed on the regrowth and keep the plants from getting too big. One way to manage the grazing is to rotate the livestock to other areas when the feed is low and then reintroduce the livestock when vegetation reappears.

3. For a natural herbicide recommendation, you might try a citrus oil, vinegar, and soap mixture. The citric acid and acetic acid work to desiccate the leaves, and the soap acts as a sticking agent. This herbicide is only a "burn down" chemical, and will not kill the whole plant. Repeated treatments will be necessary to use up the energy reserves in the roots as they resprout.

4. Burning poison ivy is a commonly recommended control option. However, when burned, poisonous particles are released in the smoke and can produce an allergic reaction in the eyes, throat, lungs, and skin.

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Permalink What resources are available to help with installing an agroforestry planting?

Answer: The following electronic databases can help you choose plant materials for your agroforestry project.

The USDA's Natural Resources Conservation Service (NRCS) maintains an extensive database at In the column on the left, under Plants Topics, you will find several ways that you can find plants that meet different criteria. "Characteristics" might be a good place to start. Fact Sheets and Plant Guides also provide useful information on specific choices.

Another resource is the Arbor Day Foundation’s Tree Guide, which offers many useful tools.

For comprehensive help planning your installation, consider reviewing the two volumes of Edible Forest Gardens, by Dave Jacke with Eric Toensmeier (see citation below). These are excellent resources themselves, and they reference many other materials. In volume two, you will find nearly 200 pages of charts and tables in seven appendices. Plants are organized by many different criteria that could be helpful as you work on your design. This resource includes perennials and vegetables, as well as trees and shrubs.

The Natural Resources Conservation Service (NRCS) has designed some online tools that might be useful, as well. Most of them are available on the National Agroforestry Center's website (under Tools).

In particular, NRCS’s CanVis can help you visualize how a planting will look immediately upon planting and shows its appearance as the planting ages. It is probably best used with an NRCS professional who is familiar with the program. For more information, visit

Jacke, Dave with Eric Toensmeier. 2005. Edible Forest Gardens. Vol. 1 and 2. Chelsea Green Publishing Co., White River Junction, VT.

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Permalink What can you tell me about controlling Japanese beetles in fruit trees?

Answer: Kaolin clay is probably your best bet for organic control of Japanese beetles on apples, plums, and pears. It's not quite so good for peaches because the peach fuzz retains the clay and thereby presents a marketing problem. Other pros and cons of Surround kaolin clay are addressed in the ATTRA publication Apples: Organic Production. Some other possible approaches to controlling Japanese beetles are outlined below.

Japanese beetles can be major pests of ripening and ripe fruit. This is a serious obstacle because there are few pesticides (organic or otherwise) that are both effective against these beetles and usable up to the day of harvest. Some botanicals— such as rotenone— can legally be used even the day of harvest according to current label restrictions; however, none have proved adequate for June and Japanese beetle control.

Consequently, organic growers have to resort to other methods to control these pests. Hand picking, trapping, exclusion with row covers, and reducing the immatures (grubs) in the soil with tillage, milky spore disease, and/or beneficial nematodes have all been attempted by growers with varying degrees of success. Targeting the grubs requires advance planning—the beneficial nematodes and milky spore disease are not effective against adult beetles. Grubs can be especially plentiful in undisturbed pasture or turf soils. Tillage and soil treatment with beneficial nematodes or milky spore disease are helpful in destroying pupae or grubs, but since the adults can fly in from relatively distant sites, it is often impractical to till or treat enough ground adjacent to the fruit planting to effectively suppress a local population.

Commercial traps that use these pheromones for trapping the beetles are available through mail-order garden supply companies, but growers and researchers alike caution that they can end up attracting more beetles to the planting than the traps can handle, making the problem even worse. So, if you use the traps, be sure to use enough of them and clean them out regularly to make room for more beetles.

Perhaps your best bet would be to both spray your fruit trees with the Surround kaolin clay as well as put out traps away from your orchard. The Surround will "push" them from your trees as the traps "pull" them elsewhere.

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Permalink What information can you give me on designing small-scale intensive vegetable plots?


Answer: Thank you for your recent request for information from ATTRA, the National Sustainable Agriculture Information Service. The following letter will provide information and resources for designing vegetable gardens for family-sufficiency on small plots.

If I recall, you are involved in Permaculture design and are very familiar with the biointensive method. These two design systems, which are very different, lay out designs for feeding 4-6 individuals. I say this because the research based on these systems shows the productivity of the systems and not just in yields. This includes soil and plant health, inputs, space, and energy (especially for biointensive in terms of calories).

For Permaculture, or rather perennial polycultures, the research and designs of Dave Jacke and Eric Toensmeier cannot be overlooked. This includes their research and discussions involving the substitution of perennials in place of annuals. If you are not familiar with Dave and Eric's 2-book volume, Edible Forest Gardens, you will find it fascinating. Eric also has a book published titled, Perennial Vegetables. Sepp Holtzer is a commercial farmer, but his designs target maximum efficiency and yields in small areas. There is some great information on Sepp online at

As a side, I remember an email you sent asking about designing a large plot of land. It mentioned a garden, woodlot, pastures, etc.... There is no set equation for formulating how to utilize land as there are variables that specifically address one's own needs. That said, I would like to refer you to Holistic Management International (HMI). HMI focuses on a specific management tool for designing and restoring land. There are several Permaculture designers who find that holistic management helps them address design components that are not considered in Permaculture. For more information on holistic management, please visit

As far as specific design layouts based on the number of individuals to feed, I must once again point to John Jeavons and the biointensive method. John and his colleagues at Ecology Action have documented their research for over 30 years. Most folks refer to his book, How to Grow More vegetables, but I would like to also refer you to all of his published findings. They are located at

Below is a list of a few resources that I use and find helpful in working with small-scale intensive agriculture. In addition to these resources, I would like to mention two other systems: Will Allen's aquaponics and Darrell Frey's Bioshelter. I have been familiar with Will Allen's urban farm for several years and had the chance to spend a week in Milwaukee on the farm in September. It wasn't until I was actually inside one of his high tunnels, looking at his aquaponic system, did I understand and appreciate his designs. It was truly magnificent. Check out Growing Power's Urban Farm at Darrell Frey is a friend of mine who lives in Northwest PA. He is a Permaculture designer and farmer and uses a bioshelter for growing. Although based on the original bioshelter model by John and Nancy Todd at the New Alchemy Institute some 40 years ago, Darrell has incorporated energy efficiency measures for sustainable vertical production. His web site is


Seymour, John. 1979. The Self-Sufficient Gardener. Garden City, NY: Dolphin Books.
- a guide to growing and using a deep bed method (biointensive).

Thompson, Peter. 1997. Self-Sustaining Garden. London: B.T. Batsford Ltd.
- based on a matrix planting and successive layers of vegetation.

Ruppenthal, R.J. 2008. Fresh Food From Small Spaces. Chelsea Green Publishing Company: White River Junction, VT.
- a square inch gardener's guide to year-round growing, fermenting, and sprouting.


Conner, Cindy. 2008. Cover Crops and Compost Crops in Your Garden. Homeplace Earth: Ashland, VA.

Wildcraft, Marjory. 2009. Food Production Systems for a Backyard or Small Farm. rooster Crows Productions: Bastrop, TX.

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Permalink What information can you give me on organic methods for controlling milkweed?

West Virginia

Answer: Thank you for your recent request for information from ATTRA, the National Sustainable Agriculture Information Service. I am pleased to provide you with information on organic control methods for common milkweed.

Common milkweed, Asclepias syriaca, is a perennial plant that commonly grows in patches. It prefers dry soils and is often found in woody areas, along roadsides, and in gardens and fields, especially if they are unmowed. Milkweed is a good source of nectar for pollinators and is a major food source for the monarch butterfly. Yet, common milkweed is considered a noxious weed in many regions of the U.S., particularly in the east. Milkweed can be toxic but common milkweed tends to have less toxicity than many other milkweeds. In fact, the toxicity levels are dependent upon certain conditions. As a noxious weed, milkweed can reduce crop and forage yields. If milkweed stands are not controlled, they become more established and the economic impact increases over the years.

Common milkweed spreads by rhizomes and by seeds that are carried by the wind. There are no approved biological or chemical controls for common milkweed that are acceptable in organic production. Therefore, controlling common milkweed is a challenge. Since it can spread by rhizomes, cultivation is not an effective control method as each root segment can regenerate a new plant. Even minimum tillage can increase common milkweed populations. Common milkweed can be confused with hemp dogbane (Apocynum cannabinum), which also spreads by seed and rhizomes. However, hemp dogbane can be controlled through flame weeding. Flame weeding is not effective for common milkweed and can actually stimulate new growth. The burning of young seedlings and dead stalks causes new growth to have taller straighter stems with longer fibers. It also stimulates flower and seed production.

There are a few suggested organic control methods for common milkweed. Pulling or digging up plants is effective, getting as much of the root system as possible. Hoeing or cutting the shoots every week or two will reduce and possible stop the plant from resprouting as well as reducing the root reserves. This can also be done by repeated mowing every three weeks. Further, adding a dense mulch layer can be effective once the plants are cut down. Please note that if you are planning on composting the plants and roots, they should be thoroughly dry so that they do not resprout.

In addition to these control methods, organic soil fertility management will also help reduce common milkweed populations. This involves proper crop rotations and the use of cover crops. Below are three resources on organic soil fertility management that may be of interest to you. All three books are available for purchase through SARE (

Clark, Andy (editor). 2007. Managing Cover Crops Profitably, 3rd Ed. Beltsville, MD: SAN Publication.
- explores how and why cover crops work and provides all the information needed to build cover crops into any farming operation

Mohler, Charles and Sue Ellen Johnson (editors). 2009. Crop Rotation on Organic Farms: A Planning Manual. Ithaca, NY: NRAES.
- provides an in-depth review of the applications of crop rotation-including improving soil quality and health, and managing pests, diseases, and weeds. Consulting with expert organic farmers, the authors share rotation strategies that can be applied under various field conditions and with a wide range of crops.

Magdoff, Fred and Harold Van Es. 2000. Building Soils for Better Crops, 3rd Ed. Waldorf, MD: SARE Publication.
- a practical guide to ecological soil management; provides step-by-step information on soil-improving practices as well as in-depth background.

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