Growing Corn:
Sweet Corn in Your Home Garden
Growing corn at home gives you something no store can: sweet corn cooked within minutes of picking, before its sugar starts turning to starch.
★ SaveThis guide covers it all: choosing a variety, planting time, block planting for full ears, care, and knowing exactly when to pick.
From My Garden
My parents' garden always had a big patch of corn. Sweet corn fresh from the garden was one of the best tastes of summer.
Here in the Willamette Valley, early to mid-May is our usual window for planting corn, after the soil warms up following our wet spring.
These days, good friends with a huge garden share their sweet corn with us.
Charlotte
On This Page
Free Charts for Growing Corn
Click any chart to open a full-size PDF you can print and keep in the garden.
Choosing a Variety for Growing Corn
Sweet corn comes in three main groups: standard, sugar-enhanced, and supersweet. They differ in flavor, tenderness, and how long they stay sweet after picking.
- Standard (SU): old favorites like Golden Bantam and Country Gentleman. Great old-fashioned flavor, and they sprout in cooler soil.
- Sugar-enhanced (SE): sweeter, more tender, and they stay sweet longer. The most popular choice for home gardens, like Kandy Korn, Bodacious, and Peaches and Cream.
- Supersweet (SH2): the sweetest, and they hold their sugar longest, but they need warm soil and must be kept away from other corn.
In the Willamette Valley and other cool-spring areas, standard and sugar-enhanced varieties do better than supersweet. Where summers are short, choose varieties under 75 days.
Popcorn and decorative Indian corn grow the same way, but are picked fully mature and dry.
When to Plant Corn
Corn needs warm soil. Plant after your last frost, when the soil is at least 55°F; 60°F and up is better. Supersweet types need 65°F.
Planting in cold soil is the most common mistake. The seeds rot instead of sprouting.
Don't start corn indoors. It grows a deep taproot fast and doesn't transplant well. Sow seeds right in the garden.
In most areas, corn goes in between late April and early June, depending on your zone. Check your dates with the planting calendar.
Plant a small block every two weeks from your frost-free date into early summer, so the harvest comes over several weeks instead of all at once.
Planting Corn in Blocks
★ SaveThe most important rule in growing corn: plant in blocks, not long rows. Corn is pollinated by the wind. Pollen falls from the tassels onto the silks of nearby plants.
Plant at least four short rows side by side instead of one long row, so pollen can reach every ear.
Full sun and rich soil. Corn needs at least 8 hours of sun and is a heavy feeder, so work in plenty of compost before planting.
Plant seeds 1 inch deep, 6 to 12 inches apart, in rows 30 inches apart. Thin to one plant every 12 inches when seedlings are 4 to 6 inches tall.
★ SaveRaised beds work too. A 4 x 8 bed holds 16 to 20 corn plants in a block, and the soil warms faster in spring.
Caring for Corn Through the Season
Water is most important at three times:
- While seeds sprout: keep the soil evenly moist.
- At tasseling and silking: dry soil now is the main cause of ears with missing kernels.
- While kernels fill: steady water makes full, plump ears.
★ SaveCorn is hungry for nitrogen. Side-dress with a nitrogen-rich fertilizer or a shovelful of compost when plants are knee-high, and again when tassels appear.
Weed early, and shallowly. Corn roots are near the surface. Once the corn is knee-high, it shades out most weeds.
Corn earworm is the most common pest. Three to five days after the silks appear, put a few drops of mineral oil or Bt on each silk cluster.
Tiny or half-filled ears? Usually not enough fertilizer. Corn in sandy soil needs feeding every two or three weeks. Tall plants with small, partly filled ears may need more phosphorus.
Pollination: The Key to Full Ears
Every strand of silk leads to one kernel. If a silk doesn't get pollen, that kernel never fills, and the ear has gaps.
Only room for a row or two? Shake the tassels over the silks each morning to help.
★ SaveKeep different types apart. Supersweet corn must be 250 feet from other corn, or tassel at least 10 days apart, or the kernels turn starchy. If you grow only one variety, you don't need to worry.
Harvesting Sweet Corn
Sweet corn is at its best for only two or three days. Most varieties are ready 18 to 24 days after the silks first appear.
Watch the silks. When they are brown and dry at the tips but still a little green at the base, the corn is close.
★ SaveDo the fingernail test. Peel back the husk a little and press a kernel. Milky juice means it's ready. Watery juice means wait. Doughy means you waited too long.
Pick in the morning, and cook or refrigerate it right away. Even a few hours at room temperature takes away sweetness.
★ SaveToo much to eat at once? See Freezing Corn to save that summer taste.
Growing Corn Organically
★ SaveSweet corn is easy to grow organically. Enrich the soil with compost or an organic fertilizer.
Choose a variety suited to your climate from your local garden center, and you likely won't need any sprays.
The Three Sisters: Corn, Beans, and Squash
★ SaveThe Three Sisters is one of the oldest ways of growing corn in North America. Corn holds up the climbing beans, the beans feed the soil with nitrogen, and the squash shades the ground.
See How to Grow Green Beans, How to Grow Squash, and the Companion Planting Chart.
Growing Corn Questions
- How many corn plants do I need?
- Each plant gives one or two good ears. For a family of four, a block of 30 to 40 plants, planted in two or three batches, is a good start.
- Why are my ears only partly filled?
- Poor pollination, usually from one long row or dry soil at silking. Plant in blocks of at least four rows and water well while the silks are out.
- Can I grow corn in a raised bed?
- Yes. A 4 x 8 bed holds a block of 16 to 20 plants.
- How long does sweet corn take to grow?
- Most varieties take 60 to 100 days from planting. Short-season varieties are best where summers are cool.
More reading: the University of Minnesota Extension guide to growing sweet corn has a detailed variety chart.
More Vegetable Growing Guides
My short garden email, Get the Dirt, comes Saturday mornings.
Sign Up for My Free Newsletter