Sowing buckwheat

When to sow

Sowing to reduce the likelihood of damaging weather is critical to success with buckwheat. Summer sowing should be timed to avoid flower blasting during the hottest part of summer, and to allow the crop time to mature before frost. There should be no hot weather (>90o) after flowering begins and at least ten weeks of frost-free growing weather. In the Northeast, mid-June through mid-July is the best time to sow. Ideal sowing times are June 15 to 25 in Maine, June 25 to July 5 in cooler parts of New York (e.g. Southern Tier, Catskills), and mid July in near the Great lakes and the Finger Lakes. Check your local weather records carefully to determine the earliest and latest safe date to sow.
To minimize flower blasting, sowing should be timed for vegetative growth during the warmer part of the summer, and flowering and set seed during the cooler late summer. Although flowering lasts for several weeks, virtually the entire crop is normally set during the first 10 days of flowering (6 weeks after sowing). During this critical flowering period, flowers are sensitive to temperatures over 90°F, with the optimum being 64°F.
For the crop to mature, it needs ten to twelve weeks between sowing and frost, and during this time it needs about 1300 Growing Degree Days (50-86°F). The shorter days in September also reduce the potential yield of late crops, but also helps synchronize seed maturity.
For your location, identify the time when there are at least 10 weeks until frost, but no more than 4 weeks left when temperatures are likely to exceed 90°. To find the approximate sowing dates, consult the map below. Sow earlier at higher elevation; sow later to reduce excessive growth.

 Optimal sowing dates predicted for Manor buckwheat by a climate model. The dates minimize the risk of both flower blasting (>86°F at bloom) and frost (<28°F before maturity). Use these predictions as a general guideline only, because the model has not been verified.
Spring sowing is also possible, but the early crop must be windrowed rather than direct-combined because the plants are still green when cut. In areas where hot weather has caused flower blasting in the past, spring sowings can start to bloom before the weather gets hot. The main risks associated with spring sowings are late frost and weed problems. Sowing can be done when the soil at least 50°F, with good emergence only above 55°F. The seedlings are quite sensitive to crusting and to muddy conditions.

A map of sowing dates