Why Is My Corn Not Filling Out with Kernels?
Corn ears with missing kernels are most often the result of incomplete pollination, usually during hot, dry, or windy weather when silks were emerging. Grow corn in blocks, keep soil moist from tasseling through silking, and check ears for poor silk development or pest injury.
Every silk on a corn ear connects to one potential kernel and must receive pollen for that kernel to develop. Pollen is shed from tassels for only a limited period, often over several days, while fresh silks need to be exposed and receptive. Missing kernels scattered across an ear usually indicate pollination was incomplete.
Plant corn in a block rather than one or two long rows. A block at least four short rows wide improves the chance that wind carries pollen from tassels to silks. For a small garden, planting 16 or more plants in a compact square or rectangle is much more reliable than a single row.
Water is especially important from tasseling through the first two to three weeks after silking. Corn often needs about 1 to 1½ inches of water per week, and more may be needed in hot, dry, sandy conditions. Drought can delay silk emergence, dry silks before pollination, and reduce kernel development.
High heat, especially above about 95°F, can shorten pollen viability and increase stress during pollination. There is little a gardener can do during a heat wave beyond watering deeply, maintaining mulch or cultivation for moisture conservation, and avoiding additional plant stress. Planting at the locally recommended time can help move pollination outside the hottest period.
Earworms and other insects may feed at the tips of ears, while birds or other animals can remove kernels after they form. Tip gaps alone are often normal, particularly if the rest of the ear is well filled. Inspect husks and ear tips for feeding, remove damaged ears promptly, and use physical exclusion methods where practical.
Do not harvest too early. Sweet corn is generally ready about 18 to 24 days after silks first appear, when silks are brown and dry and a punctured kernel releases a milky liquid. Clear, watery liquid means the ear is immature; thick or doughy contents indicate it is past prime.
Frequently asked questions
Can I hand-pollinate corn?
Yes. On a calm morning, gently shake stalks so pollen falls from tassels, or collect pollen in a container and dust it over fresh silks for several days.
Why are only the tips of my corn ears missing kernels?
A few unfilled tip kernels are common because those silks emerge last and may not receive pollen. Major tip gaps can also reflect drought or heat during silking.
Does corn need to be planted in more than one row?
For reliable home-garden pollination, yes. A compact block of multiple rows is much better than a single long row.
General guidance for US home gardens. Conditions vary by region and season; check with your local Cooperative Extension office for site-specific advice. Page updated Aug 4, 2026.