If you’re planning your garden in East Tennessee, knowing when to plant corn is your first step to a successful harvest. Getting the timing right makes all the difference for strong stalks and full ears.
Corn is a warm-season crop that loves heat and hates frost. Planting too early risks cold soil stunting your seeds, while planting to late can expose pollination to summer drought. The sweet spot depends on your specific location and that year’s weather patterns.
This guide will walk you through the optimal windows, soil prep, and simple tips to get your corn off to the best start.
When To Plant Corn In East Tennessee
The classic rule for East Tennessee is to plant corn after the last spring frost date. For most of the region, this falls between April 10th and April 20th. However, soil temperature is a more reliable guide than calendar date alone.
You should aim to plant when the soil at a 2-inch depth consistently reaches 55°F to 60°F. You can use a simple soil thermometer to check this. Corn seeds will rot in cold, wet soil, so patience truly pays off.
Here’s a more detailed regional breakdown:
- Lower Elevations & Valleys (e.g., Knoxville, Chattanooga): The earliest planting window typically opens in mid-April. You can often plant safely from April 15th onward, weather permitting.
- Plateau Regions & Higher Elevations (e.g., Cumberland Plateau): Here, frost dates are later. It’s wise to wait until late April or even early May, from April 25th to May 10th.
- Successive Plantings: For a longer harvest, don’t plant all your seed at once. Sow a new block every 10-14 days until early July. This staggers your maturity dates.
Why Soil Temperature Trumps the Calendar
Air temperatures in spring can swing wildly in East Tennessee. A warm week in March might tempt you, but the soil below is often still chilly. Planting into soil below 55°F leads to poor germination and weak seedlings.
A soil thermometer is a small investment for big results. Take measurements for a few consecutive mornings in your garden bed. When it holds at 55°F or above, you’re likely good to go. Warm soil wakes the seed up quickly, leading to fast, uniform emergence.
Preparing Your Garden Bed for Corn
Corn is a heavy feeder. It needs rich, well-drained soil and plenty of nutrients to thrive. Here’s how to get your bed ready:
- Choose a Sunny Spot: Corn needs full sun—at least 6-8 hours of direct sunlight daily.
- Test Your Soil: A soil test from your local extension office (UT Extension is great) tells you exactly what your soil needs. Corn prefers a pH between 6.0 and 6.8.
- Amend the Soil: Work in 2-4 inches of well-rotted compost or aged manure a few weeks before planting. This improves drainage and adds organic matter.
- Add Fertilizer: Use a balanced fertilizer (like 10-10-10) at planting time. Follow package rates, or apply about 2 pounds per 100 square feet, worked into the top few inches of soil.
The Importance of Planting in Blocks
Corn is wind-pollinated. Planting in long, single rows often leads to poorly filled ears because pollen misses the silks. Instead, plant in blocks of at least 4 rows side-by-side. This setup helps the wind reliably transfer pollen from the tassels (tops) to the silks (on the ears).
Step-by-Step Planting Guide
- Create Rows: Space rows 30-36 inches apart. This gives plants room to grow and allows you to walk between them for weeding.
- Plant Seeds: Sow seeds 1 to 1.5 inches deep. Place them 8-12 inches apart within the row. If your soil is sandy or it’s very dry, plant on the deeper end of that range.
- Water Gently: Water the planted rows thoroughly to settle the soil around the seeds. Keep the soil consistently moist (not soggy) until seedlings emerge, which usually takes 7-14 days.
- Thin Seedlings: Once seedlings are a few inches tall, thin them to the strongest plant every 12 inches. Crowded corn won’t produce well.
Early Season Care and Protection
Your work isn’t done after planting. Early care sets the stage.
- Weed Control: Weed carefully around young corn plants, as their roots are shallow. Mulching with straw or shredded leaves can supress weeds and retain moisture.
- Fertilize Again: When corn is about knee-high (12 inches tall), side-dress with a nitrogen-rich fertilizer. This is crucial for stalk and ear development. Scratch it into the soil alongside the rows and water it in.
- Watch for Pests: Early season pests like cutworms or birds can be a nusiance. Cutworm collars (made from paper cups) protect stems. Covering rows with garden fleece can also deter pests and give a slight warmth boost.
What If You Plant Too Early or Too Late?
Mistakes happen. Here’s what to expect.
Too Early: Seeds may sit dormant, rot, or produce weak seedlings that are purple-tinged (a sign of phosphorus lock-up in cold soil). If a surprise frost threatens emerged seedlings, cover them with row covers or even old blankets overnight.
Too Late: Planting after mid-July risks the corn maturing during late summer heat and drought, which can hurt pollination. It also pushes harvest into fall rains, which can promote mold. Choose faster-maturing varieties if you’re planting late.
Choosing the Right Variety for East Tennessee
Selecting a corn suited to your goals and season length is key. Look at the “days to maturity” on the seed packet.
- Early Varieties (70-80 days): Good for early harvests and for higher elevations. Examples include ‘Silver Queen’ (white) or ‘Early Sunglow’.
- Mid-Season Varieties (80-90 days): Reliable for most gardeners. Examples include ‘Bodacious’ (yellow) or ‘Peaches and Cream’ (bi-color).
- Late Varieties (90+ days): Need a long, warm season but often have exceptional flavor. Ensure you have enough frost-free days left in your season.
Always save some seeds from a packet for that successive planting a couple weeks later.
FAQ: Planting Corn in East Tennessee
Can I plant corn in May in Tennessee?
Yes, May is an excellent and very common time to plant corn in East Tennessee. Soil is reliably warm, leading to good germination. In fact, many gardeners find mid-May plantings perform exceptionally well.
What is the latest you can plant corn in Tennessee?
For a reasonable chance of harvest, aim to get your last planting in the ground by early to mid-July. Use an early-maturing variety (under 80 days) to beat the first fall frost, which usually arrives in mid-October for most of East Tennessee.
How do you prepare soil for sweet corn?
Start with a soil test. Add compost or aged manure to improve texture. Work in a balanced fertilizer before planting, and plan to side-dress with a nitrogen fertilizer when plants are knee-high. Ensure the planting site gets full sun all day.
Does corn need a lot of water?
Yes, corn needs consistent moisture, especially during tasseling, silking, and ear development. Aim for about 1 inch of water per week, more during hot, dry spells. Water at the soil level to avoid washing pollen off the tassels.
Can I grow corn from store-bought corn?
It’s not recommended. Most sweet corn from grocery stores are hybrid varieties. Seeds saved from them won’t grow true to the parent. Also, many commercial crops are picked so mature that the seeds are to dry or old to germinate well. It’s best to buy fresh seeds from a garden supplier each year.
By following these guidelines and paying close attention to soil temperature, you’ll master the timing for planting corn in your East Tennessee garden. A little planning leads to the sweet reward of homegrown corn on your table all summer long.