When Do I Plant Corn

If you’re wondering when do i plant corn, you’re asking the most important question for a successful harvest. Getting the timing right is the biggest factor for growing full, sweet ears.

Corn is a warm-season crop that loves heat and hates cold soil. Planting too early is a common mistake that leads to poor germination or weak plants. This guide will walk you through the simple signs to watch for so you plant at the perfect moment for your garden.

This is your core rule: plant corn after the last spring frost date and when the soil is warm enough. Corn seeds will simply rot in cold, wet ground. Let’s break down what that really means for your planting schedule.

The Two Non-Negotiable Soil Conditions

Before your seeds go in the ground, check these two critical factors. Ignoring them is the fastest way to failure.

Soil Temperature: Your soil must be at least 60°F (16°C). For ideal and rapid germination, aim for 65–70°F (18–21°C). Use a simple soil thermometer to check at a 2-inch depth in the morning.
Soil Moisture: The soil should be moist but not soggy. If it clumps into a wet ball in your hand, it’s too wet. Wait for it to dry out a bit to avoid seed rot.

Using Your Last Frost Date as a Guide

Your average last spring frost date is your starting point. You can find this date through your local university extension service. Most planting calendars are based on this date.

For most regions, plant corn 2 weeks after your last expected frost date.
If you’re using a short-season variety or have a very long summer, you can sometimes plant a bit later for a fall harvest.

Regional Timing Examples

General timelines can help you plan. Always prioritize soil temperature over the calendar.

Northern Climates (shorter seasons): Late May to early June is typical. Using black plastic to warm the soil a few weeks early can really help.
Midwest & Temperate Zones: Often from mid-April through May. Succession planting every two weeks can extend your harvest.
Southern/Warmer Climates: Planting can start as early as March. Some areas can even plant a second crop in late summer for a fall harvest.

How to Plant Corn Correctly

Once timing is set, proper planting ensures strong growth. Follow these steps.

Choose a Sunny Site: Corn needs full sun—at least 6-8 hours of direct light daily.
Prepare the Soil: Work in several inches of compost or aged manure. Corn is a heavy feeder and loves rich, well-draining soil.
Plant in Blocks, Not Rows: For good pollination, plant seeds in a block of at least 4 rows side-by-side, rather than one long row. This helps the wind distribute pollen effectively.
Sowing Seeds: Plant seeds 1–1.5 inches deep. Space them about 9–12 inches apart within the row, with rows 30–36 inches apart.
Water Thoroughly: Water well after planting and keep the soil consistently moist until seedlings emerge.

What About Succession Planting?

To avoid a giant glut of corn all at once, don’t plant all you’re seeds on the same day. Instead, sow a new block every 2 weeks. This staggers your harvest so you get fresh ears over a longer period. Just make sure your final planting date allows enough days to maturity before your first fall frost.

Troubleshooting Poor Germination

If your seeds don’t come up, a few things could be wrong. Here’s what to check.

Cold Soil: This is the #1 cause. Seeds decay before they sprout.
Planting Too Deep: Seeds use up all their energy before reaching the surface.
Birds or Pests: Birds sometimes pull up new sprouts. Loose row covers can protect them.
Old Seeds: Corn seed viability declines after a couple years. For best results, use fresh seed each season.

Caring for Your Corn After Planting

Good timing gets them started, but care keeps them growing.

Watering: Corn needs about 1 inch of water per week. Water deeply at the soil level, especially once tassels and silks appear.
Fertilizing: Side-dress plants with a nitrogen-rich fertilizer when they are about knee-high (12 inches tall). This fuels their major growth spurt.
Weeding: Keep weeds down, especially while plants are young. Shallow cultivation is best to avoid damaging the corn’s shallow roots.

Signs Your Corn is Ready for Harvest

Your timing work pays off at harvest. Look for these signs about 3 weeks after the silks first appear.

Silks turn dry and brown.
The ear feels plump and firm.
The kernels exude a milky, not clear, liquid when punctured with a fingernail.

FAQ: Your Corn Planting Questions Answered

Can I plant corn in July?
It depends on your frost date. Count back the “Days to Maturity” on your seed packet from your first fall frost. If you have enough days, you can plant a late crop. Choose a fast-maturing variety.

How late is too late to plant corn?
If the ears won’t mature before your first fall frost, it’s too late. Corn is very sensitive to frost, which will kill the plant.

What happens if you plant corn to early?
Seeds will likely rot or germinate very poorly. Surviving seedlings will be stunted and more susceptible to disease and pests.

Can I start corn indoors?
It’s possible but not often recommended. Corn transplants can be tricky and don’t always handle the shock well. If you have a very short season, start in biodegradable pots 2-3 weeks before outdoor planting time to avoid disturbing the roots.

Does corn need a lot of water?
Yes, especially during pollination and ear filling. Drought stress during silking leads to poorly filled ears with missing kernels.

By focusing on soil warmth and frost dates, you solve the main puzzle of when do i plant corn. Patience in the spring leads to a much more bountiful and sweet harvest come summer. Listen to the weather and your soil thermometer—they’re you’re best guides for perfect timing.