When to Plant Tomatoes: Seed-Starting and Transplant Dates by Frost

Tomatoes are frost-tender, and even a few chilly nights can stall young plants for weeks. Setting them out a little late almost always beats setting them out too early. Here is the timing, step by step.

Step 1: wait for frost to pass and the soil to warm

Texas A&M AgriLife Extension is direct: do not set out tomato plants until all danger of frost has passed. University of Minnesota Extension adds that the soil should have warmed as well, and UMD notes that warm-season crops planted into cold soil don't get off to a good start. If your forecast still shows nights in the 40s, wait, or protect the plants with a row cover or wall-of-water.

Step 2: dates by last frost

These windows match our planting calendar: start seeds indoors 5 to 7 weeks before your average last frost, and transplant 0 to 2 weeks after it.

Regional examples: in central Maryland (last frost around mid-April), UMD lists tomato seeds indoors from mid-March and transplants from May into early July. In most of Minnesota, UMN counts back from planting out in mid-May or later. University of Florida IFAS lists tomato transplants for February in North Florida and January in Central Florida.

Step 3: starting seeds indoors

• Don't start too early. UMN suggests sowing 5 to 6 weeks before you plan to plant out, and warns that older, larger plants are harder to manage indoors.
• Keep them warm to sprout. A heat mat at 75 to 85°F speeds germination (UMN), then give seedlings bright light so they don't stretch.
• Harden off. Over about a week, set seedlings outside for a few more hours each day before transplanting.
• Or buy plants. Texas A&M notes most families need only a few plants and suggests buying healthy, green transplants about 6 to 8 inches tall.

Step 4: planting day

Step 5: fall tomatoes in hot-summer areas

In Texas and much of the South, tomatoes often stop setting fruit in the peak of summer, and a second planting gives a fall harvest. Texas A&M says to transplant fall tomatoes about 100 days before the first expected frost. Count back from your first fall frost date, and choose earlier-maturing varieties if the window is tight.

End of the season

Tomatoes don't survive frost. UMN suggests picking all the fruit before the first frost; mature green tomatoes can ripen indoors at room temperature.

Where tomatoes go in the garden

Keep tomatoes and potatoes apart and rotate the whole nightshade family; UMN suggests 3 to 4 years before tomatoes return to the same spot. See what to plant with tomatoes for basil, marigolds and other good neighbors, and when to plant potatoes if you grow both. Peppers start indoors a few weeks before tomatoes and go out a little later; see when to plant peppers.

Frequently asked questions

When should I plant tomatoes outside?

After your last spring frost, once nights stay warm and the soil has warmed, usually 0 to 2 weeks after the average last frost date.

When should I start tomato seeds indoors?

About 5 to 7 weeks before your last frost date. UMN suggests 5 to 6 weeks before you plan to plant outside.

Is it too early to plant tomatoes in April?

It depends on your frost date. In much of the South April is normal; in northern areas April is usually too early unless the plants are protected.

What happens if I plant tomatoes too early?

Cold soil and chilly nights stall growth, and frost can kill the plants. Waiting a week or two after the last frost usually gives better results than planting early.

When should I plant fall tomatoes?

Texas A&M suggests transplanting fall tomatoes about 100 days before the first expected frost.

How deep should I plant tomato transplants?

Deeper than they grew in the pot. Leggy plants can be laid in a trench, and roots will grow along the buried stem.