Old-timers say corn is best when the water is boiling by the time you get back inside with the corn directly after picking. These's definitely truth to that - sweet corn loses sweetness (the sugar turns to starch) within minutes of picking - but even day-old homegrown corn will taste better than 2/$1 ears at Safeway.
Corn comes in a few distinct categories based on selective breeding:
SU is "normal sugary", which is the old standard
SE/SE+ is "sugary enhanced", the new standard for home gardens, the '+' is even sweeter
Sh2 is "supersweet" - you don't want this in the home garden. It's bred for shelf life, so this is what you buy in the store, but is not as reliably sweet as SE and needs to be isolated from other corns in the garden.
Synergistic Hybrids are a mix between Sh2 and SE, which again are bred at least partially for shelf life, which I don't care about.
Harvest Time: JUL-SEPT (in central Maryland)
Spacing: 12-18" in row, 20-36" between rows
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Gardening Tips:
Old timers have a lot of sayings about corn. For growing it, they say "knee-high by the Fourth of July." So that's a good goal, but is not setting a high bar in my opinion. I'm well past that point in mid-June and picking corn by mid July.
Corn needs to be planted in boxes more than in rows - corn is wind-pollinated, so the wind has to knock the pollen off of one stalk and onto another. Most spacing schemes are somewhere near 18"x24", but many farmers go to 30" between rows because that's the spacing they use for bean planting, and they use the same machinery. The most aggressive planting scheme I've seen for planting corn is a 1 foot by 2 foot spacing in Jim Crockett's Victory Garden book. He seems to think it works, but I tend toward slightly larger spacing.
Jim also passes along that you should plant corn "when the oak leaves are about as big as a squirrel's ear." That's the old-timers talking again. I don't know when that happens, but most suggestions seem to indicate that you should plant right about at the last frost. Seeds in the ground can tolerate frost, and those above ground can tolerate a light one. Crockett goes an extra step and plants a second crop in July, starting the seeds in 6-packs in late June and transplanting after harvesting the main crop. Perhaps I'll try that, but it seems like more of a pain than it's probably worth.
Also note that you can plant SU and SE corns together, but not Sh2. Sh2 corns are easily cross-pollinated, and it's not god for this type, because the corn reverts to field (dent) corn, which is, for all intents and purposes, inedible.
The three biggest problems in my opinion with corn are:
- Too much at once: you need to plant lots of corn at once so they pollinate one another. This means that in July, they are all ready at the same time. You can plant corns with different maturation dates, but that only extends the season a few weeks.
- Bugs: Bugs love corn. There are little black bugs that come in through the top opening and make the corn all nasty. These can be mitigated by choosing corn varieties with very tight husks. This may help with little corn worms too (earworms). I've been considering a good spray of Diatomaceous Earth on the cobs once nearly ready as well.
- Bigger pests: squirrels, groundhogs, and deer all hang out in the garden and pull off the cobs.
Picking corn is all about judgment - you're looking for three things: (1) dried silk hanging outside the husk - if it's not completely dry, the corn's not done. (2) high angle - the cob should be hanging a large angle off of the stalk, usually more than 45 degrees. (3) rounded end - the end of the cob should be rounded, not lightly tapered.
These are all judgment calls, so it may take a while to get the art down. If all else fails, just open them in the field.
Fertilizer Notes:
Native Americans dropped a fish head (probably not a whole fish head, that's ridiculous, but that's the story) in with their corn kernels at planting time. Apparently fish heads have a lot of nitrogen, so that seems to fit the recommendations I've seen for corn fertilization:
- 2 courses of Urea (46-0-0) or 21-0-0 before corn is 1' tall
- Side-dress at 12-18" plant height with high-nitrogen fertilizer (University of Illinois)
- 10-10-10 at planting, sidedress with 20-10-10
- pretreat with 10-10-10 at 5 lb./100 sq. ft. Nothing noted during growing season. (Crockett's Victory Garden)
The general consensus is that you should pre-fertilize with at least 10-10-10 and sidedress with something high-nitrogen like Urea once or twice early on (let's say at 4 and 7 weeks)
Preservation Notes:
Corn can be frozen off or on the cob. To do it off the cob, blanch the ears whole for 4-6 minutes, then transfer to ice water to cool. Cut off the kernels, bag, remove air, and freeze.
To freeze it on the cob, you just skip the cutting step. The bags are harder to remove air from, so wrap the corn in saran wrap before freezing.
Matt's Garden Notes:
2013: First year for corn, growing two kinds - Delectable (SE, 82 days) and Early Sunglow (SU, 68 days). 1 oz. of each was enough to plant about a 10x9 plot, which contains five rows, with some left over. Early Sunglow was ready in early July, Delectable mid-July. Got almost entire amount (2 ears/stalk) and was enough for us to freeze some.
Recipes using Corn: