Buckwheat

Sow only after every danger of frost has passed

Wait until the last spring frost is behind you and the soil is thoroughly warm, then drill seed 0.5 to 1.5 inches deep in 6 to 8 inch rows at 40 to 60 lb per acre. If you broadcast instead, use 70 to 100 lb per acre and rake, roll or cultipack it in to get seed-to-soil contact. In warm soil it germinates in 3 to 4 days. Buckwheat is a warm-season annual with no frost tolerance whatsoever, and its seedlings are the most sensitive part of its life. It also has a weak taproot and shallow surface roots, so a seed left lying on the surface without soil contact simply never establishes.

⚠ Do not sow buckwheat on ground that received atrazine, imazethapyr, halosulfuron or fomesafen on the previous crop, because the herbicide residue injures it. NRCS also advises against planting buckwheat in or next to commodity wheat ground in Colorado, Kansas, Minnesota, Montana, Nebraska, North Dakota, Oregon, South Dakota, Washington and Wyoming, and against wheat within 2 calendar years after buckwheat, because buckwheat is an allergen that contaminates wheat export shipments.

Midsummer catch crop: sow into the gap an early crop leaves

When an early vegetable or grain comes off and the bed would otherwise sit bare, buckwheat is the fastest cover you can establish. Sow any time the soil is around 70F or warmer and enough frost-free weeks remain for the growth you want, at 55 to 65 lb per acre drilled or 70 to 80 lb broadcast. Do not treat it as a fall cover crop. Buckwheat needs soil near 70F to germinate and covers warm ground faster than any other cover crop, so a midsummer bed can grow a smother crop instead of a weed crop. But it has no frost tolerance, so a sowing made too late grows little and is killed outright by the first light frost, and later sowings make shorter plants with an abbreviated bloom.

Keep water to it through bloom and seed fill

From the first flowers through seed set, do not let buckwheat go dry. This is the one window where irrigation pays, and it lasts several weeks because the crop flowers continuously rather than all at once. Hot drying winds during this stretch are as damaging as drought itself. Dry soil, hot winds and heat stress during bloom make buckwheat abort flowers and seed at high rates, which cuts yield drastically even though the plant still looks healthy. Its root system is small, only about 3 percent of the plant's weight against 6 to 14 percent in cereal grains, so it has very little stored moisture to coast on.

Feed it less than you think, especially nitrogen

Fertilize from a soil test when you prepare the bed, and keep nitrogen low. Nitrogen rates above about 50 lb per acre can cause lodging in wet years, and after a legume or on ground with good organic matter buckwheat often needs no nitrogen at all. Phosphate is the nutrient it actually responds to. Buckwheat outperforms small grains on poor soil and is built for low fertility, carrying a root system that is only about 3 percent of the plant's weight against 6 to 14 percent in cereal grains. Extra nitrogen buys tall succulent stems on that small anchor, and wind or heavy rain lays the crop flat, which makes it hard to harvest and costs yield outright.

Green manure: mow it within 10 days of the first flowers

If you are growing buckwheat as a green manure or weed smother rather than for grain, mow or till it under no more than 10 days after the plants begin to flower, which is roughly 4 to 7 weeks after sowing. It is killed easily by mowing, and the residue breaks down fast, so get the next crop or cover planted promptly rather than leaving bare soil. Seed matures only about 10 days after flowering and shatters off the plant almost as soon as it is ripe. Let the crop get past that point and you have not grown a cover crop, you have sown a weed that volunteers in whatever you plant next.

⚠ If you are growing buckwheat for pollinators and beneficial insects instead, it needs at least 20 days of bloom for minute pirate bugs to complete a generation, which runs past the 10-day reseeding threshold. Take that tradeoff deliberately and still kill the stand before the earliest seed hardens, or accept that you will be fighting volunteers.

Check the stand a week after sowing and patch the gaps

Walk the planting about one week after seeding and look for bare gaps more than a foot across, then reseed them. Where deer and turkeys are thick, expect them to browse young buckwheat hard, since those are the worst pests it has in the Northeast. Buckwheat controls weeds by one mechanism only, closing a dense canopy fast. A gap wider than about a foot never closes over, and weeds take that ground for the rest of the season, which is why Bjorkman's team recommends inspecting and replanting at exactly one week.

Cut for grain when about three quarters of the seed has turned brown

Swath when flowering is nearly finished and about three quarters of the seed is brown and hard, leaving roughly a quarter still green. Green seed finishes ripening in the windrow. Cut in the morning while the crop is wet with dew, or during damp weather, because dry stems shatter seed as you cut them. Stems are succulent and need a good while to dry before threshing. Buckwheat is indeterminate: the top of the plant is still flowering while seed at the base is already ripe and dropping. There is no moment when the whole crop is ready, so waiting on the last seed just costs you the first, and the crop keeps flowering until freeze-up if you let it.

⚠ Get it swathed ahead of a killing frost. Frost on a standing crop causes considerable harvest difficulty plus yield loss from shattering and lodging. Set the combine cylinder to 600 to 800 rpm or lower and widen the concave clearance if seed cracks or hulls. Store at 13 percent moisture for long-term storage, and dry at no more than 110F.