Long considered a crop for southern climates, new cultivars of popcorn have emerged that require less than 90 days from planting to harvest making it possible to grow popcorn in nearly any garden in the U.S. Seeds purchased from garden supply stores produce the most reliable popcorn, but popcorn kernels from the grocery store can be grown. The downfall of grocery store popcorn is not knowing the days to maturity and risking hybrid kernels that do not produce true to type.
Select a growing area for popcorn that receives full sun and is at least 25 feet from sweet corn to prevent cross-pollination.
Prepare the soil for popcorn by tilling to a depth of 8 to 10 inches and removing roots, rocks and other debris. Break up any clods of soil with a garden rake or hoe. Rake the area smooth.
Test the soil and amend to maintain a pH of 6.0. Follow the recommendations that accompany the soil test for adjusting pH.
Add organic matter to the soil to improve texture and drainage. Spread 2 to 3 inches of well-rotted manure (fresh manure robs the soil of nitrogen as it decays and may burn young roots) or compost over the garden bed and work it into the soil with a garden tiller or hand tools.
Mark rows for planting with the edge of a hoe. Space rows 2 to 2 1/2 feet apart. Several short rows assist in pollination and are preferable to one long row.
Plant popcorn seeds in the spring after the danger of frost has passed in your area, as young shoots are sensitive to cold weather. Sow to a depth of 1 inch, spacing seeds 8 to 10 inches apart.
Water to moisten the soil and keep the soil moist until seedlings emerge in 7 to 14 days depending on the cultivar and soil temperature.
Side dress with high nitrogen fertilizer when plants have eight to 10 leaves and again when silk appears. Spread 34-0-0 fertilizer (¼ to ½ pound to 100 foot row) along the side of the row and work in well with a hoe.
Keep soil moist, particularly during ear formation and tasseling. Drought conditions decrease kernel formation and may affect harvest.
Allow corn to mature on the plant until leaves are dry and silk is dark. Harvest and shuck the corn. Place ears in a mesh bag and hang in a dry well-ventilated area to dry. Remove kernels from ears when they are hard and glossy. It may take up to two weeks for kernels to dry sufficiently after harvest. Store kernels in an airtight container.