Vegetable / Warm season
Sweet Corn
Also called sweetcorn, maize
Plant it in a block or expect gappy ears
Plant out byMay 18zone 6
- Family
- Grass (Poaceae)
- Sun
- Full sun (6+ h)
- Difficulty
- Some care
- Days to harvest
- 60-100 days
- Spacing
- 12 in apart, rows 30 in
- Pot size
- Beds only
- Frost
- Tender
- Start
- Direct sow
- Water
When to plant
Showing .
Averages for a typical garden in the region. Your local frost dates may differ by 2-3 weeks, check a local source.Too late this year (try fall)
In zone 6, sow or plant outdoors Apr 27 to May 18. Average last frost Apr 20, first fall frost Oct 20.
Units
Corn is pollinated by wind, and that changes how you plant it. Pollen falls from the tassels onto the silks below, and every silk leads to one kernel. A single long row lets most of that pollen blow away, which is how you end up with ears missing half their teeth. Plant a few short rows side by side instead, so the stalks share pollen. My kids like shaking the stalks in July to watch the pollen drift down, which helps a little too.
The other watch-out wears a mask. Raccoons seem to know the night before you plan to pick, and one family can strip a patch. Corn earworms slip in through the silk tip. Supersweet types planted near regular sweet corn can cross and turn starchy, so Clemson suggests keeping them far apart or planting them about a month apart.
Sow seed straight into the bed once soil reaches about 60 degrees F, often two to three weeks after your last frost. Supersweet seed wants 65 or it may rot. Space plants about a foot apart. Ears are usually ready about three weeks after silks show. Look for brown, dry silks and a milky squirt when you press a kernel. Each stalk gives only one or two ears, so a 4×8 bed of corn is grown for taste, not volume. Pots rarely work, since tall stalks tip over and pollination gets spotty.
Things to consider
- Corn drinks most when tassels and silks appear. A dry week then can leave ears short and poorly filled, so water deeply at that stage. Mulch laid down once plants are knee high holds moisture in the bed.
- The sweet milk stage is short, only a day or two above 85 degrees F. Check daily once the silks brown, and cook or chill the ears soon after picking. Sugar starts turning to starch within hours, which is why fresh corn tastes so different.
- It shades whatever grows to its north. Put the block on the north side of the bed so shorter crops still get sun, or grow squash and pole beans under it the old way. Tall stalks catch wind, so hill soil around the base once plants are a foot tall.
Good neighbours
Keep apart
Pests to watch for
Corn earwormsRaccoonsCutwormsJapanese beetles
Questions about growing sweet corn
Can I grow corn in containers?
It is possible with a short variety and a wide tub, but results tend to be thin. Corn needs neighbors for pollination, so several pots grouped tightly beat one lonely stalk. Most growers get better ears from a small block in the ground. If you try it, choose a short variety and keep the tubs out of strong wind.
What are the Three Sisters?
It is an old planting of corn, climbing beans and squash together. The corn holds up the beans, and the broad squash leaves shade the soil. Sow the corn first and add beans once stalks are several inches tall, so the beans do not smother it. It takes more room than you might expect, so try it in one corner first.
How do I keep raccoons out of my corn?
A sturdy fence with an electric wire near the top is what most growers trust. Paper bags or mesh over the ears can save a small patch. Some people pick a day early rather than lose the lot. Motion-activated sprinklers work in some yards, at least for a while.
Save this crop
Pin it to a garden board so it is there when planting time comes round.
Similar crops
Sources
General guidance for home gardens. Frost dates are averages for a zone or region; check a local source (in the US your county extension office) for local timing.