Tomatoes go outside one to two weeks after your last spring frost, once the soil has warmed. Seeds are started indoors six to eight weeks before that. Find your zone below, or enter your ZIP code for dates based on the weather station closest to you.
Tomato dates for your ZIP code
Planting times based on university extension guidance (UNH, Cornell, Purdue, Minnesota, Nebraska and UMass Extension). Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Tomato planting dates by zone
| USDA zone | When to plant |
|---|---|
| Zone 3 | May 30 – June 6 |
| Zone 4 | May 23 – May 30 |
| Zone 5 | May 15 – May 22 |
| Zone 6 | May 8 – May 15 |
| Zone 7 | April 24 – May 1 |
| Zone 8 | April 7 – April 14 |
| Zone 9 | March 10 – March 17 |
Not sure of your zone? Look it up by ZIP code.
Why tomatoes wait for warm weather
Tomatoes are warm-season plants. A frost kills them, and cold soil and cold nights stall their growth even without frost. They do best once the soil is at least 65 °F and the air at least 60 °F, which is why transplants go out one to two weeks after the last spring frost rather than on the frost date itself.
How to plant tomatoes
- Start seeds indoors about six to eight weeks before your transplant date, in soil kept at 60–70 °F.
- Harden off the seedlings by setting them outside for a few hours a day, increasing the time over several days.
- Plant deep. Set plants at the depth of their first leaves. Leggy seedlings can be laid at an angle, with only the top 5–6 inches above the soil.
- Space them out: 1–3 feet apart, or 12–18 inches for staked indeterminate plants.
- Add support right away. Use 6-foot stakes for indeterminate tomatoes and cages 4–5 feet tall for determinate ones.
- Feed lightly at planting with a starter fertilizer, and again with nitrogen once the first fruit sets.
Harvesting tomatoes
Pick tomatoes when they are fully colored, or when they are 60–90% colored and let them finish ripening indoors. Keep ripening and ripe tomatoes at 50–55 °F and out of the refrigerator, which ruins their flavor. When a frost is forecast, pick mature green fruit (the inside is filled with gel) and ripen it at 65–70 °F.
Frequently asked questions
When should I start tomato seeds indoors?
About six to eight weeks before you plan to transplant. The dates above count back from your zone’s transplant window.
Can I plant tomatoes before the last frost?
Not without protection. Frost kills tomato plants, and cold soil slows them down even when it doesn’t freeze. Wait one to two weeks after your last frost date.
What is the difference between determinate and indeterminate tomatoes?
Determinate plants grow about 3–4 feet tall and ripen most of their fruit over a couple of weeks. Indeterminate plants can reach 7–8 feet and keep producing until frost.
Why are my tomato flowers falling off?
Usually because of temperature. Nights below 55 °F and very hot weather both cause tomatoes to drop flowers without setting fruit.
Sources. Planting dates use the median frost dates of each USDA zone, calculated from NOAA climate data for every ZIP code in the zone.