The Sex Life of Sweet Corn

14 August 2009, written by Barbara Pleasant

My little patch of sweet corn is only 3 rows deep, so I plan to help with the pollination process. Unlike most garden crops, which are pollinated by insects or vibration, corn depends on wind to bring its male and female parts together. In a small planting, pollen shed by the tassels at the tops of the plants (the male parts) may blow away before enough of the microscopic grains land on the silks at the ear tips (the female parts). Fortunately, it’s easy enough to lend a hand.

Corn’s Sexy Secrets

Most sweet corn is in pollination mode for about 10 days. When the tassels at the tops of the plants show dangling anthers (shown above), and the ear tips show hairy tufts of silk, the pollination process is underway. Here’s how it works: a pollen grain falls on a sticky strand of silk and imbeds itself. For the next 12 to 24 hours, the pollen grows a tube down the length of the silk to a waiting ovary. If all goes well, a corn kernel is born. Excellent pollination produces ears that are filled with wall-to-wall kernels; poor pollination leads to ears with lots of missing kernels.

How to Help

The best supply of fresh, high-quality pollen is shed from mid to late morning, so that’s the best time to assist in the pollination process. There are three main ways to go about it:

Take a broad, dry pan (such as a pie tin plucked from the recycling bin), and hold it beneath tassels as you go through the patch and tap the stalks to shake out pollen. Free-floating pollen will likely land on many of the silks, and some will accumulate in your pan. Sprinkle pinches of the powdery pollen over the silks of ears on the edges of your planting, as well as those on the upwind side of your plot.
Snip off a few anther-bearing branches from the tassels that look like they are freshly opened. The day’s new anthers often appear yellowish because they are full of fresh pollen (one dangling anther can hold 2500 grains of pollen). Gently touch the tassels to waiting corn silks, as shown here.
If your corn is so tall you can’t easily reach the tassels, you can cut off entire tassels and brush them over silks like a wand.

Hang in There

It takes about 5 days of intermittent pollination to form a big, well-filled ear of sweet corn, so I try to revisit my patch daily when it’s in "full tassel". The orgy ends when the tassels stop shedding pollen and the silks dry to brown. From there it’s a short wait for your reward, because sweet corn is usually ready to pick only two weeks after pollination is completed.

By Barbara Pleasant