Hand-Pollination of Corn

By Staff
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Hand-Pollination of Corn

Learn how to pollinate corn by hand with this technique.

By Micaela Colley & Jared Zystro

The Seed Garden (Seed Savers Exchange, 2015) by Micaela Colley & Jared Zystro and edited by Lee Buttala & Shanyn Siegel brings together decades of research and hands-on experience to teach both novice gardeners and seasoned horticulturists how to save the seeds of their favorite vegetable varieties.

You can purchase this book from the MOTHER EARTH NEWS store: The Seed Garden.

Hand-pollination of corn is fairly easy and is com­monly used by seed savers when they are unable to provide a sufficient isolation distance between varieties.

Corn plants are ready to be pollinated when the male inflorescences, called tassels, are fully expanded and the anthers begin to shed pollen. Some preparation for corn hand-pollination, however, must be done before the plants begin to flower. When tassels start showing above the uppermost leaves of a plant’s stalk, it is time to scout for and cover developing ear shoots (female inflorescences). Learning to identify and prop­erly isolate emerging shoots is the most difficult part of the hand-pollination process. Ear shoots develop on the lower part of a corn stalk, in the axil between the main stem and a leaf. As these shoots become visible, they must be covered with special wax coated shoot bags before their hair-like styles, called silks, emerge. Each pollinated silk will produce a single kernel of corn.

Some manipulation of the plant is necessary to cover the shoot. First, remove the leaf next to the shoot. Some varieties have sizable husk leaves that will elongate with the developing ear; these leaves should be cut back so they will not push the bag off the ear as they continue to grow. Next, make a shallow slice in the collar (the area of leaf that wraps around the main stem) between the ear and the main stem so that the shoot bag can be securely wedged into place. Perform this step with care as the ear can be cut from the plant. Last, place the shoot bag over the immature ear, with the long side of the bag wedged into the slit in the collar. A properly bagged ear is well protected against drifting pollen and can remain covered until it is hand pollinated, but bags should be monitored to ensure that they remain in place.

Hand-pollination takes place during the time when the mature tassels are shedding pollen. Pollen is shed for at least several consecutive days and can be collected on any of these days. Tassel bags should be placed over actively shedding tas­sels in the afternoon. Hold the tassel and top leaf (if necessary) in one hand, slipping the tassel bag over them with the other hand. Fold up one corner of the bottom of the bag at a 45-degree angle and use staples or a paper clip to hold the bag securely around the stem.

That same afternoon, remove the shoot bags and trim the husk tips on each shoot to expose a pencil-wide area of silks in the center. This should be done quickly to limit the duration any devel­oping silks are exposed to airborne pollen, and carefully, as cutting too low will damage the ear shoot. Replace each shoot bag immediately after trimming.

The next morning, after any dew has evap­orated, gather the corn pollen. Gently bend the bagged tassel over and tap the bag several times to shake the pollen from the anthers into the bag. Keeping the bag tilted so the pollen cannot fall out, slip the bag off the tassel. After all tassel bags have been collected, combine the pollen into a single tassel bag; this pollen mixture will be used to pollinate many ears.

All of the silks in an ear shoot are receptive at the same time. To hand-pollinate an ear of corn, remove the shoot bag and sprinkle the bulked pollen over the silks. Since being trimmed the day before the shoot should have formed a short, even flush of silks that can easily be dusted with small amount (about 1⁄16 teaspoon) of pollen. Work quickly to limit the duration of the silks’ expo­sure to wind-borne pollen. After each pollination, cover the shoot with a tassel bag, securing the bag in place by wrapping the edges of the bag around the stem and stapling the two sides together. Place labels at the base of each pollinated shoot to iden­tify the isolated ears at harvest. The bags can be removed once the silks have dried and the kernels have started to develop.

When the tassels begin to emerge, start scouting for emerging shoots. Corn shoots need to be covered before the silks emerge. Cut back husk leaves, if present. Remove the main leaf next to the shoot so the shoot bag can be slipped into place. Place a shoot bag over the young shoot and secure it by wedging the bag between the shoot and the main stem.

In the afternoon of the day before pollination, place tassel bags over the tassels. Fasten the bottom of the bags tightly around the stem using staples or paper clips. The anthers will shed pollen into the tassel bags the next morning.

On the same afternoon that the tassels are covered, prepare the shoot by cutting the tip of the husk to expose the silks. Immediately replace the shoot bag. In the morning, collect the tassel bags. Quickly remove the shoot bags and transfer pollen onto the silks, which will have grown past where the tip of the shoot was cut the previous day. Immediately after dusting silks with pollen, cover the shoot with a tassel bag to prevent other pollen from reaching the silks. Secure the bag in place by stapling it around the main stem.

For more on seed saving, see our Seed Saving Guide.

Reprinted with permission from The Seed Garden, by Micaela Colley & Jared Zystro, edited by Lee Buttala & Shanyn Siegel and published by Seed Savers Exchange, 2015. Buy this book from our store:The Seed Garden.