Summer Sweet Corn

The sugary, succulent blast of flavor that comes from biting into fresh-picked, lightly steamed, summer sweet corn is like no other. Indeed, fresh corn on the cob is a quintessential highlight of the season.

Out in the garden, before your corn even reaches the table, the visuals of tall, rustling stalks, on their way to producing cobs of deliciousness, aren’t too shabby, either.

Many folks already have their corn up and growing, and fresh ears have beckoned from farmers markets and roadside stands for a month or two now. But if you move quickly, there’s still time to plant for a fall harvest.

Getting Started

Summer sweet corn requires a block of space.

Granted, we’re not talking about the acreage consumed by unending rows of cornfields marching across Iowa, Illinois, Nebraska and parts of California. However, a long, single row won’t do. The ears are wind pollinated, so the stalks should stand shoulder to shoulder in as many directions as possible.

At a minimum, plan for a five- by five-foot block or a four- by eight-foot raised bed.

Also, while many summer vegetables require six to eight hours of direct daily sunlight, corn prefers 10 hours or more. Heat, fertile soil and ample moisture are essential, too.

Whether you garden in heavy clay or sandy soil, dig down eight to 12 inches, break up any clumps, then mix in homemade compost, well-aged manure or bags of medium-textured organic amendment, along with a few handfuls of kelp meal to supply trace minerals. Or go up, rather than down, by building a raised bed containing at least eight to 12 inches of loose, fertile soil.

Planting from kernels, rather than seedlings, is more economical and effective, as a seed packet costs only a few dollars, yet contains 50 to 75 kernels, and the roots of transplants might be tangled or overgrown by the time you set them in the garden.

Given the need to sprint to the finish, choose a short-season or early-season variety that’s ready for harvest in 65 to 70 days, rather than 85 days or longer.

Sow the kernels on traditional long mounds or straight into the ground. I’ve tried both methods with equal success.

Space the kernels four to six inches apart, in rows two to three feet apart. Bury the kernels half an inch to an inch. By alternating the kernels in a diamond pattern, I’ve managed to squeeze three rows into a four- by eight-foot bed, but three rows into a five-foot square block is better.

Water daily until the corn sprouts, which should take a week to 10 days. For mounds, flood the furrows between the rows; on flat ground, run inline drip irrigation tubing or soaker hose along each row.

Once the stalks are two inches tall, back off watering to once or twice a week. Also thin the plants to nine to 12 inches apart. Any closer and you’ll end up with scrawny stalks and punky ears.

Up and Growing

Corn offers plenty of interaction.

The plants are heavy feeders, gobbling up nutrients in their haste to grow five to six feet tall, produce a couple of tasty ears and complete their life cycles in just a few months. Nitrogen is key to that fast, leafy growth.

When the stalks reach a foot tall, side-dress the rows with alfalfa meal, blood meal, chicken manure, compost, fish emulsion or other high-nitrogen organic fertilizer. Watch for yellowing leaves. If you’re watering adequately, the discoloration may indicate insufficient nitrogen.

You might side-dress another time or two, but stop when the tassels form, which is usually about three weeks before harvest. For an early-season, 70-day variety, the stop-time is about 50 days after germination.

Each stalk bears just one tassel, a male flower, on top. At several leaf joints along the stalk, ears or female flowers will swell, then produce silks atop their husks.

Wind and gravity help the pollen from the tassels drop onto the silks. In vast commercial cornfields, broad pollination occurs, the ears develop full kernels inside the husks and tasty cobs of corn are the result.

Years ago, I learned that one of the best ways to ensure adequate pollination within just a few rows of corn is to whack the stalks every morning for a week after the tassels appear, to make the pollen fly. I’ve beaten on my corn with a broom ever since with excellent results. Conversely, if you don’t disperse the pollen, you’ll end up with a lot of silk and few kernels on any cobs.

Pollination is also the time to combat corn earworms, a common pest that delights in deforming your crop. Pale tan moths lay white eggs on the silks or the undersides of the leaves. The hatchlings are what worm their way into the husks, then feast inside.

To discourage the incursion, squirt a few drops of mineral oil onto emerging silks. Apply the oil every three days until the silks shrivel and turn brown.

Also, do not grow more than one variety of corn side by side, as cross-pollination can produce starchy, tasteless ears.

In addition, up the water as your stalks grow. By the time tassels form, you may be watering every other day until harvest.

Harvest

Corn is ripe when the kernels have plumped up, filled out and pop with creamy juice when pierced. You can peel back the husks to check. But don’t keep messing with the same ear. At a certain point, a husk won’t tighten, offering an inviting portal to pests instead.

Harvest your corn moments before dinner. Even with newer varieties bred to maintain a longer shelf life, don’t give the ears time to start converting their sugary goodness to starch. Simply twist off the ear, immediately steam or barbecue and enjoy.