One of the most important green manure crops is buckwheat (Fagopyrum esculentum), which is not a grain but a fast-growing, semi-succulent plant that produces nutritious triangular seeds. Buckwheat deserves frequent sowing in any garden because it attracts hoverflies and other beneficial insects, suppresses weeds, and adds bulk to the compost pile. Small plantings of garden buckwheat are surprisingly easy to handle, too.
Battling Bugs with Buckwheat
Buckwheat flowers attract honeybees and other pollinators with their morning nectar flow, but they also support healthy populations of smaller beneficial insects. Mounting evidence suggests that blooming buckwheat give a significant boost to important beneficial species, particularly hoverflies (properly known as Syrphid flies but commonly called hoverflies because of their seemingly effortless ability to hover). On both sides of the Atlantic, researchers are finding that growing buckwheat nearby can deter pests of potato, broccoli, green beans, and other vegetable crops, in part by providing abundant food for female hoverflies. Most hoverfly larvae are too small to see without a magnifying glass, but they are voracious predators of aphids and other small, soft-bodied insects.
Organic growers who use buckwheat as a primary pest-prevention strategy have found that it’s important to grow buckwheat within about 20 feet (6 metres) of crop plants, which is easily done in a garden. Upright yet spindly, buckwheat plants have such shallow roots that they are easy to pull up with the flick of a wrist. A few buckwheat seeds sown among potatoes are known to confuse potential pests, and a broad band of buckwheat makes a fine beneficial backdrop for strawberries. Throughout the summer, I sow buckwheat in any spot bigger than a dinner plate that won’t be planted for a few weeks. With good weather, buckwheat can go from seed to bloom in a little over a month.
Growing Buckwheat to Control Weeds
Buckwheat’s fast germination makes it a top choice for smothering weeds. A few years ago, a section of my garden was home to a colony of field bindweed (Convolvulus arvensis), a formidable foe as weeds go. Field bindweed (often called creeping jenny) is a hardy perennial from Eurasia that winds itself around anything in its path and reproduces from root buds and seeds. But my field bindweed is now history thanks to a year of intensive cover cropping with buckwheat.
Summer weeds that do germinate alongside buckwheat are usually shaded into submission. Later, when the plants are pulled out, residual compounds exuded by growing buckwheat roots may act as natural herbicides, suppressing the germination of weed seeds.
Growing Buckwheat to Improve Soil
Phosphorous and calcium are among the most important nutrients needed by plants. Soils that are regularly enriched with organic matter often contain an abundance of these nutrients, but in forms that are difficult for plants to take up. Buckwheat has been called a phosphorus pump because of its ability to take up soil phosphorus and return it in a more plant-friendly form. When you grow a patch of buckwheat, both your garden and your compost pile reap this reward.
Buckwheat Growing Basics
Domesticated in northwestern China more than 3,000 years ago, the cultivation of buckwheat gradually spread across Russia and northern Europe. Buckwheat grows best in warm weather, yet it matures quickly enough to make a crop in short season climates. You can begin planting buckwheat anytime after your last frost date. Buckwheat planted in late spring and early summer tends to grow taller than later sowings that grow when days are becoming shorter.
I grow buckwheat to attract hoverflies and other beneficial insects and to add bulk to my compost, and I always pull up the plants before they pour their resources into developing mature seeds. A multitude of farm advisory bulletins warn that buckwheat can become weedy, but I don’t think this applies in an organic vegetable garden. In my garden, I welcome volunteer buckwheat plants, which are much easier to pull than weeds.
Buckwheat seeds are sold by most seed companies that sell cover crop seeds, though your cheapest source may be a local farm supply store that sells buckwheat seed by the pound. At health food shops, check the sprouting seed section for whole, raw buckwheat groats, which have usually had their black hulls removed, yet are still strong germinators. The word "groat" means hulled seed, which are raw and sproutable in the case of buckwheat groats sold for sprouting. But take note: Toasted buckwheat groats sold as breakfast fare will never sprout, no matter what.
By Barbara Pleasant