When to Plant Tomatoes

Tomatoes go in the garden after your last spring frost, once nights stay above 50°F and the soil has warmed to about 60°F. For most gardeners that means 1 to 2 weeks after the average last frost date. If you grow from seed, start them indoors 6 to 8 weeks before that date.

The rest of this guide explains each of those signals and how to use them together.

Step 1: Find your last frost date

Tomatoes are killed by frost, and even a few nights in the 40s slow them down for weeks. Your average last frost date is the starting point for every other date.

Look it up with our Frost Dates by ZIP Code tool. It shows two spring dates:

• The average last frost. In half of all years, the last frost comes later than this.
• The safer planting date. Only 1 year in 10 has a frost after it.

Tomatoes should never go out before the average date. Gardeners who don’t want to cover plants on cold nights wait for the safer date.

Step 2: Wait for warm nights

The frost date only tells you when freezing is unlikely. Tomatoes also need warmth. Below about 50°F at night, they stop growing and can drop their flowers. Cold soil also stunts the roots.

Before you plant, check that:

• Night temperatures in the 10-day forecast stay above 50°F.
• Soil temperature at 4 inches deep is at least 60°F. A cheap soil thermometer settles it.

In many places, especially along the coasts and in the North, these conditions arrive 2 to 4 weeks after the last frost. In the South they often arrive sooner.

Step 3: Count back to start seeds

If you start your own seedlings, sow them indoors 6 to 8 weeks before your last frost date. Younger plants are fine; older ones get tall, root-bound and slow to recover.

For example, with a last frost on April 20:

Task	Date
Sow seeds indoors	February 23 – March 9
Start hardening off	About 1 week before planting out
Plant outside	April 27 – May 4, if nights stay above 50°F

Our Seed Starting Calculator works these dates out for your own frost date.

Step 4: Harden off before planting

Seedlings raised indoors need about a week to adjust to sun, wind and cooler nights. Set them outside in a sheltered, partly shaded spot for a couple of hours, then give them a little more time and sun each day. Skipping this step leads to scorched or stunted plants.

How to plant tomatoes

• Pick full sun. Tomatoes need at least 6 to 8 hours of direct sun a day.
• Plant deep. Bury the stem up to the first set of leaves. Tomatoes grow roots along the buried stem, which makes a stronger plant.
• Give them room. In raised beds, about 4 square feet per caged plant works well. Crowded plants get more leaf diseases.
• Support them at planting time. Put cages or stakes in now; doing it later damages the roots.
• Water deeply, then mulch. Once the soil is warm, a layer of straw or shredded leaves keeps moisture even and helps prevent blossom end rot.

Planting early with protection

You can gain a week or two by warming the soil and sheltering young plants:

• Cover the bed with black plastic for a week before planting to warm the soil.
• Use wall-of-water cloches or floating row cover over new transplants.
• Keep frost cloth on hand for any late cold night.

Even with protection, don’t plant before the average last frost date. A hard freeze will still kill the plants.

Tomatoes in hot climates

In the Deep South and the desert Southwest, the problem is often heat rather than cold. Tomato plants set little fruit when daytime highs stay above about 90°F or nights stay above about 75°F. Gardeners there plant as early in spring as frost allows, and many plant a second crop in midsummer for a fall harvest.

When will I get tomatoes?

Most varieties ripen their first fruit 60 to 85 days after transplanting. The days to maturity on the seed packet or plant tag count from the day you plant out, not from sowing. Cherry tomatoes are usually the fastest; large beefsteaks are the slowest.

Quick checklist

1. Look up your last frost date.
2. Sow seeds indoors 6 to 8 weeks before it.
3. Harden off seedlings for about a week.
4. Plant out after the last frost, once nights stay above 50°F and the soil reaches 60°F.
5. Keep frost cloth ready for the first few weeks.