Corn (Zea mays). The quintessential Native American crop, corn was a staple of indigenous peoples from South America to the Great Lakes. It’s believed to have been domesticated in Mexico, and may be of the world’s oldest agricultural crops. It’s best seeded directly into the garden, in good, rich, well-drained soil, right about the time of the last spring frost. Plant it in blocks rather than long narrow rows, to improve pollination. Corn can be very drought tolerant, but ears fill best when there is good soil moisture when tassels and silk first emerge. Harvest sweet corn when the kernels are full of milky-colored juice; allow other types to remain on the stalks until fully dry. All types of heirloom corn are grown the same way. At about the time of last frost in spring, plant heirloom corn seeds directly into the richest soil available, 1-2 inches deep. Whether planted in rows or beds, allow the corn plants up to about one square foot per plant, on average. Ears fill best when dry conditions are not allowed to prevail at tasseling time. Sweet corn is picked when milky juice is contained within the kernels; clear juice is immature, and chewiness means the ear is over-mature. Flour corn is left on the plant until thoroughly dry in the fall.