When to plant tomatoes by zone
Tomatoes are the reason most people start a garden. They're also the crop most people screw up by planting too early. I get it. Those seedlings at the garden center in April are hard to resist. But a tomato planted into cold soil just sits there, sulking, while the one planted two weeks later catches up and passes it.
The trick is knowing your USDA hardiness zone and working backward from your last frost date. Here's how it breaks down across the country.
The general rule
Tomatoes need soil temperatures of at least 60°F to grow. They die at 32°F. So the math is simple: figure out when your last frost typically hits, then plant transplants outside about two weeks after that date. Start seeds indoors 6 to 8 weeks before transplanting.
That's it. Everything else is just adjusting those numbers for your specific zone.
Zone-by-zone timing
| Zone | Last frost (typical) | Start seeds indoors | Transplant outside |
|---|---|---|---|
| 3 | May 15 | March 1 - March 15 | Late May - Early June |
| 4 | May 10 | March 1 - March 10 | Late May |
| 5 | April 30 | Feb 20 - March 5 | Mid May |
| 6 | April 15 | Feb 15 - Feb 25 | Late April - Early May |
| 7 | April 5 | Feb 1 - Feb 15 | Mid to Late April |
| 8 | March 15 | Jan 15 - Feb 1 | Late March - Early April |
| 9 | Feb 15 | Dec 15 - Jan 1 | Early March |
| 10 | Rare/None | Year-round | Year-round (avoid peak summer) |
These dates come from USDA zone data and NOAA's 30-year climate normals. Your specific location may vary by a week or two. Microclimates matter: a south-facing slope in zone 5 can act like zone 6.
Want exact dates for your ZIP code? Try our free planting calendar for personalized tomato timing.
Cold zones (3-4): patience pays off
If you garden in Minnesota, Montana, or northern New England, you know the drill. The growing season is short, sometimes barely 100 days. Tomato variety selection matters more here than anywhere else.
Stick with early-maturing varieties: Early Girl (50 days to harvest), Stupice (60 days), or Glacier (55 days). These ripen before your first fall frost shuts everything down in September.
Start seeds indoors in early March. Use a heat mat, because basement temperatures in March are usually too cold for good germination. Tomato seeds want 75-85°F soil to sprout quickly. At 65°F they'll still germinate, but it takes twice as long and you don't have time to waste.
Middle zones (5-7): most of the country
This is where the bulk of American gardeners live, from Ohio to Virginia to Missouri. You have enough growing season for almost any tomato variety, including the big beefsteaks that take 80+ days.
The mistake I see most often in zone 6 is planting on tax day (April 15) because "it seems warm enough." Some years it is. But a late frost in late April can kill unprotected plants. Wait until soil temperatures consistently hit 60°F. A $10 soil thermometer is the best gardening investment you'll make.
In zone 5, harden off your transplants for a full week before putting them in the ground. Set them outside for a few hours the first day, then increase the time each day. Plants grown under lights are soft. They need time to adjust to wind and UV.
Warm zones (8-10): different problems
In zones 8 through 10, the challenge isn't cold. It's heat. Tomatoes stop setting fruit when nighttime temperatures stay above 75°F. In Houston, Phoenix, or South Florida, you're working with two growing windows: spring (February through May) and fall (September through November).
Zone 8 gardeners in the Gulf South should get transplants in the ground by late March. Zone 9 gardeners in central Florida or the Texas coast should aim for early March. Zone 10 (south Florida, southernmost Texas) can grow tomatoes from October through April, avoiding the brutal summer entirely.
Heat-tolerant varieties like Solar Fire, Phoenix, and Heatmaster were bred for exactly these conditions. Cherry tomatoes also handle heat better than large slicers.
Seed starting vs. buying transplants
Starting from seed gives you more variety options. The garden center might carry six tomato varieties; seed catalogs list hundreds. You also save money if you're planting more than a few.
But there's nothing wrong with buying transplants if you missed the seed-starting window or just don't want the hassle. A healthy 6-inch transplant from a local nursery will do fine. Avoid the leggy, pale ones that have been sitting under fluorescent lights too long.
Common timing mistakes
Planting too early is the most common error, but planting too late also causes problems. A tomato transplanted in late June in zone 5 might not have time to ripen its fruit before frost. You end up with green tomatoes in October. (Fried green tomatoes are good, but not what most people had in mind.)
Another mistake: not accounting for your specific microclimate. Urban gardens surrounded by concrete and brick are typically warmer than nearby rural areas. Gardens on hilltops are windier and cooler. Low-lying areas collect cold air and frost more often. Pay attention to what actually happens in your yard, not just what the zone map says.
Getting your exact dates
The table above gives general guidance, but your specific ZIP code has specific frost dates. Our planting calendar tool pulls USDA zone data and NOAA frost records to calculate exact windows for tomatoes and 30 other crops. Just enter your ZIP code.
The difference between "mid May" and "May 11" might not sound like much, but in a short-season zone, every day counts.