Margaret Lauterbach

Double-duty: Grow corn to support bean stalks too

Brown and dry tassels can be a signal for when to pick corn.
Brown and dry tassels can be a signal for when to pick corn. AP

It will be a while before we plant our corn (wait for the soil to warm to at least 50 degrees F.), but consider having your corn patch do double-duty, by producing ears of edible, grindable or poppable kernels, but also providing supports for pole beans. To fill out the “three sisters” complement (corn, beans and squash), plant winter squash to shade the intervening soil from weed germination. Folklore tells us that native Americans grew crops in this efficient manner.

Since we’re in charge of our own gardens, none of us really like strict rules about gardening, but these for “three sisters” growing have reason behind them: first plant corn, and when it’s a few inches high, plant a couple of pole beans a few inches from corn stalks. After those have germinated and grown a few inches high, plant winter squash, one seed per “hill” of corn. By “hill,” we don’t mean an actual rise, just the spot where your corn stalk is. The planting order is important to make growth possible for all three types of plants so they don’t shade or dominate the others prematurely.

It’s important, too, to plant corn to facilitate wind pollination. In the Treasure Valley, our prevailing daytime winds are west to east, and at night from east to west (the west end of the Valley is lower, and as air cools, it sinks and flows to a lower elevation). Some people plant corn in clusters, with the beans around each cluster. Most varieties of corn only produce one full ear per stalk.

All American corn is Zea mays, botanically. All American Zea mays includes sweet, field, popping, ornamental, flour and flint corns, the latter two usually used for corn meal. Any of these can cross-pollinate any of the others within 250 feet or less, if their projected tasseling out coincides with one another.

The really complex part of this is the various hybrid sweet corns, whether it’s se, su, sh2, syn, sh2 or ssw, identified on the seed packet after the species name. Cross-pollination between any of these results in tough, inferior sweet corn. Johnny’s Selected Seeds’ catalog, online, gives the best definitions of these types I’ve seen.

The su genotype is the oldest of them, widely available before the year 2000, and converts so quickly from sugar to starch that it became axiomatic that one had water boiling in the pot before one picked that ear of corn. The newer types tend to hold sugar longer than the su types, so you can either plant a variety that is different from one planted within 250 feet, or plant at least two weeks later than the other was planted to avoid cross-pollination. Pollination, of course, only affects the seed of a plant, not the flesh of its fruit that season, but since corn IS the seed, it will be affected.

The sugar-enhanced (se or EH) sweet corn germinates most quickly when the soil temperature is 55 to 60 degrees F. The older su type has a sugar content of about 9 percent, but the sugar-enhanced type has about double that sugar content, but the kernel skins are quite tender and fragile, so take care when harvesting. The sh2 types are called supersweet, ultrasweet or shrunken-2 sweet corn. They have about 35 percent sugar content, but tough kernel skins. This variety does not convert sugar to starch. It requires warmer soil for germination: at least 60 degrees at a depth of 2 inches.

If you don’t keep a journal of when you planted your corn so you’ll know when to harvest it, we’re all advised to wait until the silks hanging out of the ears are brown and dry. In my experience, by the time the corn is ripe there are no visible silks because earwigs have eaten them. That does not mean you have had a pollination failure. Pollination occurred before the earwigs had their way. You can feel the ears and they should be rounded instead of pointed at the end of the ear, or you can pull some husks back and peek at the condition of the kernels. Better to pick corn a little early than to pick it late.

Stop that crabgrass

Corn gluten meal is a byproduct of a wet milling process that produces high fructose corn syrup, I think. That corn syrup has been suspected of being a prime cause of human obesity, so consumption of it has been much reduced as people take better care of their health. That also reduces the supply of corn gluten meal, so it’s rather hard to find. In the past, Zamzows, D & B Supply and Edwards Greenhouse carried it. I know that D & B is not carrying it this year. Check the other sources and even Walmart, Lowe’s and Home Depot for it. I think it’s effective on crabgrass as long as the forsythia are in full bloom.

Planting fragile seeds

I usually plant lettuce indoors and later transplant it outdoors. The seed is so tiny and fragile it’s very difficult to just put a tiny layer of soil over the top, so I just lay the seed on top of moist potting mix, and hold moisture in by topping the pot with a small pane of glass (from a picture frame). Carrot seed is also tiny and fragile, but carrots don’t transplant well or easily. It’s best if you have pelletized carrot seed. If you do not, you can mix that seed with sand or radish seeds for planting outdoors.

I usually just plant carrot seed alone, distributing it in a line near a soaker hose, then firm it into the soil by pressing a 1-by-2-inch board over the seed, and leaving the board in place for a few days. Then, pick it up and if there is a hint of new green under the board, remove it so the carrots can get sunshine. Another way I’ve planted carrot seed is to lay a 4-by-4-foot piece of pegboard on a bed, then pour out all of the carrot seeds I’ve accumulated and brush it into the holes. Move it about an inch in any direction and weight it down, and then again, leave the pegboard in place for a few days

Send garden questions to or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.