Effects of cold temperatures on spring crops

Corn and soybean are warm season crop and require at least 50 degree soil temperature for adequate germination.

The effect of cold temperatures on corn during spring time is limited because the growing point of the plant is located below ground until the plant reached about V5 stage (vegetative stage with leaf collar fully visible above ground).

Parts of plant above the soil surface can be damaged by low temperatures but will grow back in warmer weather conditions. This may cause plants to stunt and delay the metabolic process. Air temperature of about 25 degrees for extended period of time may cause temperature around the growing point located below ground to drop significantly causing plant to die off. On the other hand, soybean is much more susceptible to low temperatures because the growing point is exposed to low temperature once the plant emerges out from the soil surface. In this situation, even simple frost (28 to 32) can be lethal.

Wheat and oat- other major crops grown in the region are cool season crops, which therefore can germinate in cooler environment with soil temperature of about 35. Like corn, during the process of early seedling development, the growing point or crown of these crops stay below ground until the plant reached jointing stage. Frost injury after plants have reached jointing stage can sustain moderate to severe freeze injuries impacting yield significantly. Freezing temperatures at stages before jointing will cause burned symptoms on leaves and stems above ground but will grow back when weather conditions get warmer.