The Temperatures for Corn Growth

Temperature

• Corn is a warm-season vegetable that does not thrive in cold soil temperatures. The best soil temperature for growing standard sweet corn is above 55 degrees Fahrenheit and about 65 F for supersweet varieties, recommends the University of Illinois Extension. Early planting may be made if the soil is warmed with the use of black plastic with holes punched through it for planting the seeds.

Effect of Cold Temperature

• The growth of roots and shoots in corn plants correlates keenly with soil temperature. If corn is planted in cold soils with a temperature below 50 F, the seeds will absorb water but there will be no shoot or root growth. This will cause the seeds to start rotting in the soil. Even if seeds do germinate given optimal soil quality, the seedling growth will still be poor in cold soil.

Soil

• Corn grows best in deep, fertile, well-drained soil. The vegetable is a heavy feeder and requires soil amendments such as nitrogen not only at the time of planting but also throughout the growth period. Amend soil with well-rotted manure or compost prior to planting and again to 1 inch of the soil every spring. Till in the amendment deeply in soil. Apply lime during fall to maintain the recommended soil pH of 6.0 to 7.0.

Planting Recommendations

• Corn seeds are just the kernels of corn. Plant at a depth of about 1/2 inch when planting in moist, cool soil and about 1 to 1 1/2 inches deep in drier, warm soil. Recommended spacing is nine to 12 inches apart in rows with about 30 to 36 inches between rows. For effective pollination, plant a couple of rows of each variety side by side.