Buckwheat • Quick Cover Crop for Weed Control
by Lynn Byczinkski, for Johnny's Selected Seeds
Buckwheat is one of the easiest and quickest cover crops, used primarily to suppress weeds and improve soil tilth. It is a warm-weather crop that can be used between spring and fall vegetables or in preparing new ground — when planted on newly prepared sod ground, buckwheat will help rot down the sod — for vegetable or berry production in fall or the following year.
Buckwheat is an attractive plant, 2' to 4' tall, with triangular leaves and flowers of white, pink, or red. Buckwheat germinates within days of seeding and does best at a soil temperature of at least 55°F/12.8°C. It begins to flower in 4 weeks and is a source of nectar for honeybees and native pollinators. Seed matures 2 to 3 weeks after flowering and, if left in the field, provides a food source for ground-dwelling birds such as quail and pheasant. Buckwheat will be killed by light frost. It does not provide nitrogen nor does it increase soil organic matter significantly, but it does improve the soil condition within the top few inches, a benefit for vegetable seeds and transplants.
The key to using buckwheat for weed control is to provide the optimum conditions for getting it up and growing so that it will be ahead of weeds. Here are some tips for getting a strong stand and managing it for improved vegetable production in the future:
- Till in any weeds or plants from a previous crop and wait 1 week for the debris to decompose sufficiently for the buckwheat seed to germinate. Break up big clumps of soil, and create the finest seedbed possible.
- Let the soil warm up and dry out if conditions have been wet. Buckwheat seed rots easily in cold, wet soil. If the soil is extremely dry, irrigate to a depth of 1" before planting.
- Buckwheat seed should be barely covered with soil for best germination. Do not plant too deeply, but don't leave the seed exposed on the soil surface, either. Buckwheat seed can be hand-broadcast at a rate of 60 pounds per acre if care is taken to spread it evenly. Or, it can be drilled to a depth of less than 1 inch at a rate of 50 pounds per acre. If there is heavy weed pressure or you are planting organic buckwheat seed, you may want to increase the rate to about 80 pounds per acre.
- As the seed germinates, check for gaps in the stand, and reseed any that are wider than 1' in diameter. If weeds are allowed to grow in these empty areas, they will produce seeds that continue the weed cycle, and the benefits of the buckwheat will be reduced.
- The plants should start to flower about 4 or 5 weeks after seeding. If the land is needed for a fall crop, mow the buckwheat before the seeds mature. If the land won't be needed until the following year, the buckwheat can be left to reseed, and a second crop can be grown in the same season. Buckwheat will not overwinter, however, so it should be mowed and replaced with a winter cover crop in late summer or fall.
For more information, see the following resources:
- Buckwheat for Cover Cropping in Organic Farming, from USDA • NIFA • eXtension
- Buckwheat Cover Crop Handbook, from Cornell University
- Buckwheat Makes a Good Summer Cover Crop for Gardens, from Oregon State University Extension Service
- Cover Crop Database: Summary of Buckwheat, from University of California Sustainable Agriculture Research and Education Program