WICHE: Corn not on the cob? Small ears may mean poor pollination

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By Jeneen Wiche

Small stalks, small ears, poor kernel development…does this describe your corn crop this year?

If it does, there may be several factors at work.  Drought at the wrong time can stunt your corn crop (we haven’t had that this year), as can cold damage (if you put your crop out early you could see a little stunting from a late spring cold snap), poor drainage and poor soil fertility, especially nitrogen.

Corn needs what most other summer crops need:  good soil and drainage, adequate nutrients and temperatures above 60 degrees for germination and growth.  Corn is actually a heavy feeder, so healthy soil with some side dressing is a good idea to maximize the quality of harvest.

Add composted manure when preparing the planting block and then follow up with a balanced fertilizer or additional compost every two weeks or so thereafter.

Water needs are not excessive, but irrigation (if it doesn’t come naturally) when the stalks begin to flower will promote larger ear development.

The rest relies on cross-pollination.

Corn flowers and begins to shed its pollen several days before the silks actually emerge. The pollen shed continues for about a week, during which most of the action takes place in late morning.

It is rare for the pollen of the same plant to fertilize itself. The pollen usually floats to other plants or travels down the tube of the silk where it finally reaches the female flower. 

Sweet corn for eating is one of those crops best grown en masse in the field.  Good cross-pollination, often facilitated by a breeze, needs to occur between different corn plants. Each silk that comes from the top corresponds directly to a kernel inside.

If the silk isn’t pollinated, then the corresponding kernel does not develop, which is pretty darn cool, really. 

The problem with backyard garden corn is that people often just plant a few rows, which usually results in poor pollination because, when the breeze hits, it just blows the pollen over the single neighboring row, and it pollinates nothing!

In order to improve cross-pollination and ensure a full ear of corn, plant large blocks of corn instead of a few long rows.

The most common pest of corn is the corn earworm (and maybe a hungry bunch of raccoons!).

The adult moth of the earworm lays her eggs on the silks of corn.  Once the eggs hatch, they begin feeding on the silks, working their way down into the husk, where the real prize awaits, the developing kernels of corn.

Commercial growers often use insecticides, but for the home gardener this is not necessary, because there is generally only one earworm per ear (they eat each other if there is more then one).

The corn is still edible. Simply cut off the end that has been eaten by the corn earworm.

One organic approach to deterring corn earworms is dropping a small amount of vegetable oil in the middle of the silks as they begin to form.  I’ve not tried it but it is worth a shot of you have the problem. 


Corn is ready to harvest when the silks dry and turn brown to black in color.

Peel the husk back a little and pierce a kernel with your fingernail.  If a milky juice squirts out, you are ready to go. 

Sweet corn undoubtedly has high sugar content, but it is best if it is eaten within 12 hours of harvest because as soon as it is picked, the sugar in the corn begins slowly to turn to starch.

If you are not ready to eat your harvest, keep it cool in the refrigerator or process it for freezing or canning.