Sign up for the
Weekly Harvest Newsletter!

Published every Wednesday, the Weekly Harvest e-newsletter is a free Web digest of sustainable agriculture news, resources, events and funding opportunities gleaned from the Internet. See past issues of the Weekly Harvest.
Sign up here

Sign up for the Weekly Harvest Newsletter

What Is Sustainable Agriculture?

Master Publication List

Search Our Databases

Urban Agriculture

Energy Alternatives

Beginning Farmer

Field Crops

Horticultural Crops

Livestock & Pasture

Value-Added Food Products

Local Food Systems

Food Safety

Marketing, Business & Risk Management

Organic Farming

Pest Management

Soils & Compost

Water Management

Ecological Fisheries and Ocean Farming

Other Resources

Sign Up for The Dirt E-News

Home Page

Contribute to NCAT


Newsletter sign up button

· Privacy Policy · Newsletter Archives

RSS Icon XML Feeds

RSS 2.0: Events, Breaking News, Funding Opportunities Atom: Events, Breaking News, Funding Opportunities


NCAT strives to make our information available to everyone who needs it. If you are a limited-access or low-income farmer and find that one of our publications is just not in your budget, please call 800-346-9140.


How are we doing?


Home  > Question of the Week

Question of the Week

Permalink What effect will buckwheat that is cut, swathed, and left on the ground have on grass growth the following year?

Answer: If the buckwheat was swathed and then combined for the seed, the residue should have been uniformly spread out the back of the combine. If, however, the buckwheat was left in the swathed windrow, the grass may have a more difficult time emerging in the spring.

If there was substantial residue in the windrow, you might want to go over it with a quick rake just to spread everything out. This will help ensure even grass emergence in the spring. However, if there is not a lot of residue, it may break down by spring time and be just fine.

Buckwheat is not technically a wheat, but is a broadleaf crop instead. It has much less carbon in its residue than wheat and should break down fairly quickly. How long it takes will depend on the amount of residue, the temperature, and the rainfall in your area.

Cornell University is a good resource for information on buckwheat management. You can access Cornell’s Department of Horticulture website at and then use the search box to find relevant information.

North Dakota also grows a lot of buckwheat and has excellent Extension information. You can access the NDSU Buckwheat website at

You may also be interested in the fertility benefits of buckwheat to the following grass crop. Buckwheat and mustards do acidify the root zone and seem to take up phosphorus more efficiently than the cereal grain crops. Some organic farmers claim that this helps with phsphorus availability to the next year's crop. Initial research at Montana State University has suggested this is not the case, however. While buckwheat can use phosphorus more efficiently than other crops, the only benefit seems to come to the buckwheat crop itself and not to the subsequent crop. The best sources of phosphorus in an organic system are; animal manure, bone meal, and rock phosphate.

Send feedback » Permalink


Permalink What should I be considering in preparing my vegetable plots for winter?

Answer: While winter may be the least attractive season for your vegetable plots, there are still a lot of important things that occur during the winter months. Fall is the time to put your farm’s plots to sleep so that they may be ready to spring into motion when winter begins to thaw.

There are a number of options and, as always, they will differ depending on your own needs and the specific climate that you function within.

Winter is a time when your soil can get some necessary TLC. All vegetable plots can benefit from regular regiments of cover cropping, compost, and mulch.

Cover Cropping
There are a number of things that happen when a bed is nicely cover-cropped before the winter months:

• the soil is protected from the elements, such as wind and rain erosion and extreme temperatures
• soil texture is maintained—roots aerate the soil; microorganisms find a suitable climate to live, eat, excrete, and die in; and water retention is elevated
• nutrients are replenished and protected from leaching caused by winter rains (legumes in particular replenish nitrogen in the soil)
• weeds are suppressed

Furthermore, when you are ready to plant in the spring, the cover crops can either be incorporated as green chop in compost or used as mulch.

In Situ Compost
In situ (in place/in bed) compost is simply building a compost pile directly on top of your vegetable plots in the fall, hoeing it under the spring, and planting directly on top of that. In situ compost follows the same theories as thermophillic compost in that it is a balance between carbon and nitrogen that is most conducive to the micro- and macro-organisms present in the pile. Bury green chop and other nitrogenous materials (such as chicken manure) under a generous layer of straw and let it sit over the winter. Covering the bed with plastic may help speed the process.

Sheet Mulching
Another interesting option, especially if you are putting in new beds or a new border, is to sheet mulch. Essentially, sheet mulching is a cold composting process that builds new beds and suppresses weeds. To create a sheet mulch bed, lay cardboard over the area you wish to grow on, wet it thoroughly, and then begin to layer materials. You can be creative, but the general idea is to build compost on top of the bed. Alternate layers of green material (nitrogenous) with brown (carbonaceous) like you are making lasagna. Cap it with a layer of mulch and let it sit over the winter.

Trench Compost
Trench composting is similar to in situ and sheet mulching. To trench compost, dig a trench and fill it with compostables, before capping the trench with soil and straw. In the spring, either dig in the soil and plant directly into the new compost, or dig it out and place it on a bed next to the trench, thus utilizing the trench as a pathway.

Mulching invites some similar beneficial aspects of cover cropping—specifically, protecting the soil from the elements. Layering finished compost over a vegetable plot and then capping that with straw or decayed leaves will help maintain the tillage and nutrient integrity of your plot.

Hardy Crops
Depending on where you live, there are certain crops that can grow outside year round without cover. Quickly maturing plants like radish, lettuces, and spinach can be planted, grown, and harvested before killing frosts. Also certain Brassicas like broccoli, kale, and especially brussels sprouts prefer cooler weather. Certain root crops, such as garlic, parsnips, turnips, carrots, and onions, are planted in to the fall for spring harvest, and many of the same root crops are planted in the spring for late fall and winter harvest.

Winter time is an important period to allow the soil to rest, rejuvenate, and prepare for spring.

For more information on cover crops, see the ATTRA publication Overview of Cover Crops and Green Manures at This publication summarizes the principal uses and benefits of cover crops and green manures. Brief descriptions and examples are provided for winter cover crops, summer green manures, living mulches, catch crops, and some forage crops. It also addresses management issues including vegetation management, limitations of cover crops, use in crop rotations, use in pest management, and economics of cover crops.

For more information on compost, see the ATTRA publication Compost: The Basics at This publication gives a basic overview of the benefits of building your own compost, and general instructions for doing so.

For more information on cold hardy crops, see the ATTRA publication Specialty Crops for Cold Climates at This publication discusses ways that specialty crop farmers can continue to market products into the colder months by cultivating certain hardy crops and implementing season extension techniques.

For more specific information on sheet mulch, in situ compost, and trench composting, consult the following resources.

Send feedback » Permalink


Permalink What can you tell me about pH and soil management in blueberry production?

Answer: The proper soil pH for blueberries is 4.5 to 5.0. If you have a pH of more than 5.5, it is recommended that you amend your soil to lower the pH before planting the blueberries.

If you would like to get your soil pH below 5.0, then the materials would optimally be applied a year before planting to allow time for them to react with the soil. These materials include sulfur and acidic organic matter such as peat moss, cottonseed meal, pine needles, and pine bark. Elemental sulfur and iron sulfate are used for large adjustments in soil pH and are listed as restricted materials in the OMRI (Organic Materials Review Institute) Generic Materials List, which means that they can be used providing that certain requirements are met.

Once your soil is at the optimum pH and you have planted your blueberries, you can maintain your current level by mulching with acidic materials such as peat, cottonseed meal, or pine needles.

If you choose to add the peat moss (or other material mentioned above, excluding elemental sulfur) before planting, replace half of the back fill with the acidic organic matter. Depending on the size of your planting stock, five gallons is feasible. After planting, mulch each row four to six inches deep and three to four feet wide. Compost adds a lot of organic matter, but pine needles would be sufficient as well. Expect to lose about one inch of the mulch per year through decomposition. Replenish it every other year with one to three inches of fresh mulch and avoid allowing the depth to increase.

Since blueberries are a perennial crop, it will be difficult to manage weeds once the berries are planted. Start with as clean a bed as possible. Cover crops are a great way to prevent weeds initially, and they offer the added bonus of increasing organic matter in your beds. In order to prevent the cover crop from re-growing and becoming a weed, it will be important to provide plenty of time for the crop to break down before planting. Once you till it in, allow two to three weeks before planting to allow the cover crop to break down.

Another option for preventing weeds, once your area is tilled, is using a landscape fabric. This effectively prevents weeds while allowing air and water penetration. It is an expensive investment initially but may pay off, depending on your weed pressure. Many people use pine needles to mulch blueberries, but if your pH is low to begin with, this approach is not recommended. By far, the cheapest option would be straw.

For a summer cover crop, sudan grass or buckwheat are good choices. The seed germinates best when soil temperatures are higher. Both of these help with weed management. You can mow your summer cover and incorporate in late summer/early fall (mid-August). At this point, you can plant your blueberries or keep it standing (it will be dead) to hold the soil over the winter for spring planting.

For more information, see the ATTRA publication Blueberries: Organic Production. This guide addresses key aspects of organic blueberry production, including soils and fertility, cultural considerations, pests, and diseases, as well as marketing. It is available at

Also see the ATTRA publication An Overview of Cover Crops and Green Manures. This publication summarizes the principal uses and benefits of cover crops and green manures. It is available at

The New York State Agriculture Experiment Station has developed an online guide for cover crops. It details planting, maintenance, and incorporation information for many types of cover crops suitable in the Northeast. It is available at

Send feedback » Permalink


Permalink What can you tell me about using corn gluten meal for weed control in pastures?

Answer: The researcher who has done the most work with corn gluten meal as a natural pre-emergence herbicide is Dr. Nick Christians at Iowa State University Department of Horticulture. Dr. Christians has looked at its use on turf (as for a golf course, for example) and organic crop production. The Resources section below identifies five useful articles on Dr. Christians’ website that will shed some light on this topic.

Others also have used corn gluten meal on pasture. You should check into the cost and read through the articles identified below to get a better sense of the benefits and limitations of using corn gluten meal as a pre-emergence herbicide. Among the more important benefits:

• Corn gluten meal is a natural fertilizer as well as a natural herbicide, contributing about 10% nitrogen to the soil
• Corn gluten meal is safe to use

However, there are also limitations, including:
• Timing is important; must be applied before germination and it works for five to six weeks
• Moisture is important; it has to get wet to activate (within five days of application, according to Dr. Christians), but then you don’t want it to stay wet.

There is another limitation, which may or may not be a concern for you. If you depend on self-seeding crabgrass and clovers, you would not want to inhibit their germination. Applying a pre-emergence herbicide will also inhibit germination of valuable plants.

What weeds are most problematic on your farm? If your grazing animals are not keeping them under control, is it because of toxicity of the weeds, or some other reason? Would it be helpful to change your grazing patterns by concentrating more animals on the pasture for a shorter time, to encourage the animals to clean up the weeds?

Considering other alternatives may be warranted. If you decide to try the corn gluten meal, see the warning from Dr. Christians to “get the real thing,” not corn gluten feed or distillers grain.


Christians, Nick.
•Corn meal research
•How to use corn gluten meal
•The use of corn gluten meal as a natural preemergence weed control in turf
•Get the real thing
•A natural product for the control of annual weeds

Garrett, Howard. 2011. Corn gluten meal – Updated information 2011. June.

Trimmer-May, Denice. 2000. Optimal amount of corn gluten meal for weed control and soil amendment qualities in organic production of strawberries. SARE Final Report. Project Number FNC98-244.

eHow. No date. How to use corn gluten to fertilize pastures.

Send feedback » Permalink


Permalink How do I wash and dry biodiesel?

Answer: Washing biodiesel is easy to do and requires only water and time. Washing removes impurities, including unfiltered particulates, methanol, and glycerin.

Unwashed biodiesel will not meet ASTM, formerly known as the American Society of Testing and Materials, standards. Equipment and engine manufacturers only warranty their equipment and engines for their material and manufacturer defects. Fuel manufacturers assume responsibility for any damage caused by the fuel.

There are several common techniques for washing biodiesel, including agitation washing, mist washing, and bubble washing. The process of washing biodiesel involves mixing it with water. Water is heavier than biodiesel and absorbs the excess alcohol, catalyst, and soap suspended in the fuel. After washing and settling, the water and the impurities in the water can be drained from the bottom of the container. Several wash cycles are generally needed. The first water drained off the bottom of the biodiesel will be milky, and the final wash water drained off will be clear. Excess catalyst in the biodiesel will form soap when mixed with water, and it takes awhile for the soap to settle out.

Depending on the method used, it takes roughly one gallon of water per one gallon of biodiesel for a wash cycle. The mixing should be thorough and the water should be dispersed throughout the biodiesel. Agitation washing means stirring water into the biodiesel, letting it settle and draining it off. Mist washing is spraying a fine mist of water over the surface of the biodiesel. Tiny droplets of water fall through the biodiesel and pick up impurities on the way down. Bubble washing is done by putting a bubbler in a layer of water beneath the biodiesel. The rising bubbles are coated with water, which picks up impurities as the water travels up and then back down through the biodiesel.

After the biodiesel is washed, it should be dried until it is crystal clear. This can be done by letting the biodiesel sit uncovered in a sunny location for a few days, or it may be heated to about 120 degrees Fahrenheit for a few hours. Another popular technique is recirculating the biodiesel from the bottom of the drying tank through a shower head or sprayer suspended above the top of the open tank. This increased contact with air will dry biodiesel in about an hour, depending on humidity. Reacted, washed, and dried biodiesel may be used in any diesel engine. It should have a pH of close to 7, or chemically neutral, and it should have no methanol left in it. Although professional testing of fuel may be prohibitively expensive, simple home fuel test kits can be purchased for a reasonable price. One such kit, The Biodiesel pHLip Test, is available at

For more information on producing biofuel, see ATTRA publication Biodiesel: Do-It-Yourself Production Basics at This publication is an introduction to home biodiesel production. It includes lists of equipment and materials needed to make small batches of biodiesel. It describes biodiesel and includes cautionary notes and procedures for making test batches and five-gallon batches. An extensive resource list is also provided.

Send feedback » Permalink


Question of the Week Archives