Whether you wish to grow sweet corn, popcorn, novelty-colored corn varieties or field corn, providing corn seeds with the appropriate temperature and moisture conditions will greatly improve their germination rate. Corn seeds must absorb about 30 percent of their weight in water before they will resume active embryo growth, according to Purdue University. And germination is also more successful when the seed’s environmental temperature is 65 degrees F or higher.
Outdoor Corn Germination
Once garden soil has reached a temperature of least 65 degrees F, soak corn seeds in tepid water for approximately an hour.
Plant seeds outdoors in prepared garden soil. If your soil is heavy, with lots of organic matter, plant seeds about 1 inch deep. If your soil is sandy, plant seeds about 2 inches deep. Seeding depth varies because you want to plant seeds at a depth with uniform soil moisture. Create a trench of the desired depth, and place the seeds 8 to 12 inches apart in the row, with rows about 30 inches apart. Cover the seeds and firm the soil after planting.
Watch for seeds to emerge in about seven to 10 days.
Indoor Corn Germination
Soak seeds in tepid water about an hour.
Dampen a paper towel and place soaked seeds on it. Put the paper towel with seeds into a resealable plastic bag. Seal the bag and set it in a warm place (between 65 and 75 degrees F) away from direct sun.
Check on the bag of corn seeds periodically during the following week to 10 days. Add additional water to moisten the paper towel if it becomes dry. Plant sprouted seeds as directed in Step 2 of Section 1 above.