I sold heirloom corn for the first time at Bethlehem, Connecticut this year and I was pleased to see the enthusiasm for it! This is an info-post for those wondering how to grow and process corn, and a bit of history on corn.
A lot of people call non-yellow corn “Indian corn” but I’d like to point out- corn is native to the Americas and all corn is originally from the Native Americans. Much corn grown today has been bred for a European style agriculture of high input and high output, based on the fact that European and European-American agriculture has a huge component of domesticated animals which produce manure. Shit's gotta go somewhere, so the history of returning manure to your pasture, hay, and grain fields is a well established one. Breeding for this system encourages varieties of plants that can race to capture all those nutrients.
Many heirloom corns, closer to their Native American heritage model, are not bred for those high input systems and so typically yield less per acre (but perhaps not in head-to-head trials on un-manured ground?) However, they need much fewer inputs than the demanding types of corn we’ve bred and engineered today. Most Native agriculture was a polyculture, as well, with corn, squash, and beans being the most well-known combination. In a polyculture, you tend to breed for plants that "play well with others"- corn stalks that don't mind being climbed on by beans...squash plants that do perfectly fine in partial shade. Each individual unit is less productive than a monoculture type, but collectively, they grow more calories and nutrients per acre or per hour of labor. In short, they're effective when you remove the idea of unlimited land or cheap labor/mechanization from the equation.
So with that in mind, corn is usually direct sown in the ground after the danger of frost has past in your area. A critical number that decides how many seedlings pop out is the night time temperature. You'll see farmers in your area, many days after a final frost, still not planting corn- besides watching field conditions, they may be waiting because the night time temperatures are still too cool. The seedlings themselves are cold tolerant down to the 30's but it's the seed that matters- in that stage, it can rot from moisture and excess cool before it germinates. So that night time temp you're looking for is above 50 Fahrenheit.
If that all sounds complicated, just call June 1st good enough! But that's when weeds think it's a great time, too, so they'll all be germinating together. Alternately, corn actually starts pretty okay in cell trays. Using 128 or 98 cell trays, you can start corn 3 weeks before transplant and set them out already several inches high. Feels like cheating but it means you can till right before planting, killing weeds, and set out your little babies no trouble.
Heirloom corn can usually be hilled as its form of weed control- an old school hoe that pulls dirt towards you as you kill the surrounding weeds. Corn can be grown in rows 3 feet apart, 8 to 12 inches between each plant. If you direct sow, go for 8 inches and if you have some loss, the average gap may be 16 inches. If you go a polyculture route, you will want to sow pole beans several weeks later when the corn is one or two feet high. Any sooner and the pole beans will surpass the height of the corn and the young corn plant will be burdened with a bigger "little sister" than it can handle. If you add squash to the mix, you could just do a row of squash between two pairs of corn rows, or some ratio to that effect. The squash will sprawl (especially vigorous vining types) and fill out 5-10 feet of either side. Again, the squash can be started a bit later than the corn, but not quite as late as the beans. It has a higher germination temperature requirement anyway. It can also be transplanted and if you transplant them both at the same time it'd probably be okay. Squash wants to grow OUT and corn wants to grow UP so as long as the corn isn't directly shaded by an early huge leaf, it'll be fine.
After two hillings/weedings on an as-needed basis in June, the corn will usually be high enough to make it on its own, but any further weeding helps guarantee the health of the plant. Some heirloom plants seem to readily form second ears when well-weeded, so it does affect yield to stay meticulous.
Depending on the corn's maturation date, you'll start to see ears form on the stalk, silks come out, and tassels emerge from the top of the plant. Once the silk has shriveled up and dried, that means the pollination stage is complete, but this is still too early for harvesting dry grain corn. It may take even weeks after the silks dry before the corn is ready to pull off the plant.
Since the corn I grow and sell are open pollinated heirlooms, you can use any of the ears I sold for seed for your own corn next year. For 2019, I did not exclude the corn from getting pollinated from one type or another (as done when trying to keep a variety pure) so some of my corn is crossed and that diversity would express itself in any corn planted. A corn plant has its own male and female parts and while the male tassel does usually pollinate a fair amount of the female silks below, some silks are bred to the tassels of nearby corn plants and depending on the size of the block, considerable crossing can occur. That, however, is what makes heirloom corn so special and cool. With little effort, a gardener or farmer can cultivate a land-race of a mishmash of corn and keep selecting for whatever works in their climate.
If you're unsure of what variety you bought and want to email a picture, go for it! I sold Abenaki Calais (yellows, maroons, burgundies, some oranges), Hopi Blue (deep indigo blues), Earth Tones Dent (all kinds of greens, turquoises, browns), and a small amount of Painted Mountain (ears with massive mixes of all those described colors. Painted Mountain is a recent crossing of many, many Native American types).
For processing, my favorite thing to do is parch it (get it really dry by heating in a skillet over a fire or on a stovetop) and grinding it for flour. You can make cornbread with it, or, just toss a quarter to half cup of it in your oatmeal every morning. It's good on its own too but our modern Skittles-n-Doritos diet leaves us largely unprepared for the simplicity of corn porridge.
Parching guarantees that the moisture content isn't too high. After harvest, there is a goal to get the ears properly dry for storage, but some may still be higher content than you may like for grinding, so the parch helps. At a typical home, the easiest thing to do is get a frying pan/skillet, fill the bottom with corn, and set your stovetop on low, and let it sit for 5 or 10 minutes. No water, no oil, no nothing! In that time, it shouldn't scorch, it'll just heat up quite a bit and dry out considerably and be easier to grind. You can even eat those plain, it's like plain unsalted popcorn.