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Competency Area 4: Seeding Factors

PO 19. Know the factors used to determine optimum planting date of major Northeast crops.

Factors used to determine optimum planting date of forage crops in the Northeast

Spring seeding typically occurs in late April to early May for perennial grasses and can be as late as June 1 in southern NY and June 7 in northern NY for alfalfa. Soil moisture is generally adequate in the spring. Late summer seeding typically begins late August in southern NY and mid-August in northern NY for perennial grasses. For alfalfa, seeding should be completed by mid-August in southern NY and early August in northern NY. White mold is much more likely on summer seeded alfalfa. Broadcast seeding prior to the spring soil freeze-thaw cycles, known as frost seeding, can be successful with some species, such as red clover, but are likely to fail with other species, such as reed canarygrass and birdsfoot trefoil.

Planting date factors for corn, soybeans, and wheat

Summer crops can begin planting at minimum temperatures for germination (after mid-April or early May, depending upon location). For corn temperatures should be around 45-50°F and for soybeans 50-55°F. Small grains begin germination at 32°F so temperature is never a constraint for spring grains and almost never a constraint for winter grains.

Corn is very hygroscopic so dry soil conditions usually do not deter corn emergence in the Northeast (but lack of moisture in the seed zone can reduce emergence in the western Corn Belt). If soil conditions are very dry, corn can be planted up to 3 inches deep because the coleoptiles (seed leaf) can puncture through tough soil conditions to help emergence from deep soil depths.
Soybean have high imbibition requirement (more than 50% by weight) so soybeans are very sensitive to dry soil conditions. Soybeans also have a hypocotyl that can be broken during the emergence process under tough soil conditions (crusted soil) so soybeans cannot be successfully planted more than 2 inches deep. Adequate moisture of the seedbed can be a constraint to stand establishment in soybean, especially under an intensive tillage system.
Small grains - moisture is almost never a factor in successful establishment in the Northeast because it is usually moist when planting small grains. Small grains also have a coleoptile so under dryland conditions (Pacific Northwest, High Plains, etc.) wheat can be successfully planted up to 3 inches deep.

Soil Conditions
Under wet soil conditions, wait until the soil dries before planting (all crops) or else you run the risk of soil compaction during planting. If it is early May and temperatures are ideal but soil conditions are wet, do not plant corn or soybeans.

Pest-free date
Winter wheat planting should be delayed until after Hessian-fly-free date (Sept. 15th in most of the Northeast).

Other Factors
Growers in regions that receive late spring killing frosts may hold off on planting corn and soybeans in late April even if favorable soil conditions and temperatures occur. Growers using ridge tillers can plant corn earlier because tilled soil dries out and warms up quicker.