How to grow sweet corn from seeds

About corn

Sweet corn is a sensitive, warm-season annual crop with yellow, white, or bi-colored kernels. Corn requires a long, frost-free growing season (60 to 100 frost-free days) to grow and harvest.

Sweet corn has been farmed for thousands of years in the Americas; it is well-known as one of the Three Sisters—corn, beans, and squash—grown by Native Americans.

Corn is a type of grass! Furthermore, wind-pollinated

Corn, a grass family (Poaceae) member, relies on wind to pollinate its blooms! This is why maize is planted in blocks of small rows rather than long, single rows.

Sweet Corn Varieties

Corn is available in early, mid, and late season variants. Early-season cultivars mature the fastest, whereas late-season kinds may take the entire growing season. Plant types with varying “days to maturity” for a longer yield.

Sugary (su), sugar-enhanced (se), shrunken (sh, sh2), and synergistic hybrid sweet corn are the four basic varieties (sy). Each has a variable level of sucrose, which alters the flavour and texture of the corn. Sweeter kinds will also keep their sweetness longer after harvest. More information on the differences between these sorts can be found in the “Recommended Varieties” section below.


Plant in direct sunshine (at least 6 to 8 hours of direct sunlight). Corn plants are particular about the soil in which they grow. Because maize absorbs a lot of water, it should be well-draining but continually moist. In the fall, old manure or compost should be worked into the soil. If that isn’t possible, simply mix with seasoned compost before planting.

When to Plant Corn

  • It is not normally suggested to start corn indoors. It’s better to start them immediately in the garden to avoid disturbing their fragile roots when transferring.
  • Corn is extremely frost sensitive; do not plant unless the soil temperature is at least 60°F (16°C), or 65°F (18°C) for super-sweet types. This is usually 2 or 3 weeks following the last frost in the spring. Corn requires a long growth period of frost-free weather, so planting early is critical. See our Planting Calendar for Corn based on Frost Dates for more information (keep in mind these dates are average or typical and simply a guide).
  • Choose an early variety that will develop well before the first fall frost if you reside in a region with a shorter growing season.
  • In colder climates, a black plastic cover can be used to warm the ground; sow seeds through holes in the plastic.
  • Plant another crop of corn a couple of weeks after your initial round to extend the harvest.

Corn Planting Instructions

  • Moisten seeds, wrap in moist paper towels, and keep in a plastic bag for 24 hours to accelerate germination.
  • Instead of one long row, sow seeds 112 to 2 inches deep and 2 to 4 inches apart in short, side-by-side rows to make a block.
  • We propose a small block of 10 to 50 plants for adequate pollination.
  • You can fertilise with a 10-10-10 fertiliser during planting time; corn is designed to grow quickly. This stage can be skipped if you are convinced that the soil is suitable.
  • Water thoroughly before planting.


  • Thin the immature corn plants when they are approximately 4 inches tall, spacing them 12 to 18 inches apart for short kinds and 18 to 24 inches apart for tall variants.
  • When weeding around corn plants, take care not to injure the roots.
  • Corn has short roots and can get affected by drought, so keep it properly watered. Water your plants around 2 inches per week; more if the weather is particularly hot or your soil is sandy. Soak the soil again if it stays dry.
  • When corn is 8 inches tall, apply a high-nitrogen fertiliser to the plants. Repeat when it reaches knee height (18 inches).
  • Mulch aids in reducing evaporation around plants.
  • Mound soil at the base of 12-inch-tall plants to keep stalks straight during heavy winds.
  • Wind pollination is essential for the development of entire cobs of kernels. Gently shake the plant stalks every few days for as long as the tassels are viable to enhance the chances of every silk being pollinated. Mornings are ideal.


  • The faster corn matures, the warmer the air. It is normally ready 15 to 23 days after silking, but it might be ready sooner if temperatures are very high.
  • When two ears develop on a stalk, the upper ear matures one to two days before the lower ear.
  • At harvest, ears should be rounded or blunt, not pointed, with brown tassels and full, milky kernels.
  • Pull down some husk and pierce a kernel with your fingernail to test. It’s ready if it’s white or milky. In hot weather (above 85°F/29°C), sweet corn is at its prime for only 1 to 2 days, so check it periodically. Corn harvested a few days after the milk stage is less sweet.

How to Keep Corn

  • Sweet corn freezes well, especially if the ears are removed before freezing. Discover how to properly freeze corn.
  • Corn can also be used for other things!

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