When to Plant Tomatoes Outside: A Guide for Each Region
You have to be careful when determining when to plant tomatoes outside, especially if you live in a colder zone. These warm-weather plants are sensitive to frost, and planting too early can cause problems, sometimes leading to serious damage. Experienced gardener Sarah Jay covers how to time your plantings by hardiness zone – with some caveats!
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Every spring, I can’t wait to transplant tomatoes outdoors. But if I jump the gun and plant them too early, my seedlings can succumb to a late frost, and I’ll lose them. If I start them too late, their ability to flower and set fruit is limited by summer’s heat. So over time, I’ve learned to transplant them at just the right moment.
Tomatoes are some of my favorite plants in the veggie garden. Growers all over can start these plants from seed in winter and have tons of tomatoes by early summer. When the right timing is used to start seeds and plant them outdoors, they’ll really pop off. If you’re gardening in a mild area, they may even produce into the fall season.
If you want to grow tomatoes that don’t get out of hand, stick to determinate varieties. Indeterminates are great for gardeners who don’t mind pruning and training large vines that sometimes grow up to twelve feet tall. Multicolored types offer interest to gardens, growing tall and strong through the season. Grow them from seed as the last frost nears, and foster them indoors until they are ready to brave the elements.
Patio Choice Yellow Bush Cherry Tomato
Patio Choice Yellow Bush Cherry Tomato Seeds
The Bottom Line
Use your last frost date and your season length to guide your timing. In general, gardeners in all zones should transplant tomatoes in the garden two weeks past their final frost date. You want to wait until outdoor temperatures are 55 to 60°F (13-16°C), usually when nighttime temperatures don’t fall below 60°F (16°C), and daytime temperatures are in the upper 70s (~21°C).
If you live somewhere cold, you should know that small tomato varieties take at least two months to develop after transplanting. So ensure you have this much time at the proper temperatures for the smallest varieties. If you don’t, grow them under low hoops or indoors where you can keep the temperatures up for the best results.
Similarly, determinate varieties will produce their entire harvest all at once, whereas indeterminates will produce a little bit at a time over the entire season. Growers in colder areas should look for varieties labeled “bush” or “determinate” unless they want to cultivate indeterminates in greenhouses or hoop houses.
A Regional Guide
Now that we’ve covered the basic rules for when to plant tomatoes outside, let’s discuss some of the regional nuances. Note that the last frost dates we provide here are approximate. You should always search for your average last frost date based on your zip code. Even that date is approximate, given today’s weather extremes.
In zone 1 and other cold zones, the season might not be long enough to directly plant outdoors and grow viable fruit. Start the seeds indoors under a grow light. Use a heat mat and sow them in large seed cells to give them the best start. Then harden them off, and be careful about your transplant timing. Use sturdy covers to keep them safe in the elements.
Zones 2-4
In zone 2, the projected last frost is in mid to late May, from the 15th to the 22nd. Therefore, use our two-week guideline to determine when to plant tomatoes outside. This timing occurs early in June, preferably in the first week. Zone 3 isn’t far behind with last frosts occurring between the 1st and 15th. Zone 4 has frosts occurring from April 24th to May 1st.
In zones 3 and 4, you don’t have to get your tomatoes in the ground immediately. Both have roughly four months of growing season, so as long as you get them in the ground a few months before your first fall frost, you’ll produce plenty of tomatoes. But don’t wait too long, or you’ll miss out!
Zones 5-8
In zones 5, 6, and 7, the last winter frost occurs between March 22nd and April 7th. Zones 5 and 6 have five months, and zone 7 has six. Plant tomatoes outdoors in these zones in the second week of April to the third week of April.
Here in zone 8, my tomatoes are already in their places, with a few seedlings still in starter pots. Here I can take my time, though, as our first frost – though projected to occur in mid-November – can sometimes be delayed until December. Here is a case in point about last frost dates. They’re very localized.
So other gardeners in zone 8 who want to know when to plant their tomatoes outside should do it now, if they haven’t. To be more specific, March 13th through 28th is the general last frost timeline. So planting in early to mid-April should work out (barring an act of god).
Zones 9-12
If you live in zones 9, 10, 11, or 12, you are also at a point where you should already have yours outdoors. In these zones, frost is rare, and it makes sense to maximize your enjoyment by planting as soon as you can. You’ll likely have plenty of time in the fall if you haven’t gotten them in the ground yet, though.
Even if you have some left over from summer, you can protect them in a freak frost to see if you can continue to grow them when conditions improve. Day length does lessen in winter, but the temperatures and potential rain allow for tons of delicious tomatoes.
Key Takeaways
Remember, your season length and your last frost date are the keys to the right timing. Use your zip code to determine a more accurate but still approximate date for when to plant tomatoes outside.
When you’re deciding how long to wait to get them in their container, raised bed, or in-ground bed, consider this chart. Note that the approximate times listed in the right column are based on the earliest times you could potentially plant.
| USDA Hardiness Zone | When to Plant Tomatoes Outside |
| 2 | 1st week of June |
| 3 | 2nd week of May |
| 4 | 2nd week of May |
| 5 | 3rd week of April |
| 6 | 2nd week of April |
| 7 | 2nd week of April |
| 8 | 1st week of April |
| 9-12 | Late February is a good starting point |
Note that you can plant your tomatoes as long as you have enough days to maturity to grow them. If you live in a zone where snap freezes can occur before your average first frost, keep a cover handy to protect them and uncover when the freeze passes.
