When to Plant Tomatoes by USDA Zone (and When It's Too Late)

Plant tomatoes outdoors after frost danger has passed, when nighttime temperatures consistently stay above 50 degrees Fahrenheit and soil has warmed to about 60 degrees Fahrenheit. Start seeds indoors roughly six to eight weeks before your intended outdoor planting date.

Temperature matters more than the calendar alone. A zone number will not save a tomato planted into cold soil or a late frost, and a late planting is not automatically too late if you still have enough warm days left before fall frost.

Use the tool: Tomato Planting Date Finder. Enter your zone, your last frost date, and your first fall frost date, and it will give you a start indoors date, a transplant window, and a last safe planting date for your variety.

In this article

• When should you plant tomatoes outdoors?
• What is the tomato planting calendar by USDA zone?
• How do you tell when it is too late?
• Do seeds need more time than transplants?
• What about hot climates, where summer heat is the cutoff?
• What matters more than your zone?
• How does the Tomato Planting Date Finder work?
• Frequently asked questions

Key takeaways

• Wait until frost danger has passed, nights are consistently above 50 degrees Fahrenheit, and soil is around 60 degrees Fahrenheit.
• Start seeds indoors six to eight weeks before moving them outdoors, according to Washington State University Extension and University of New Hampshire Extension.
• USDA zones measure average annual extreme minimum winter temperature, according to the USDA Plant Hardiness Zone Map, not spring frost dates or summer warmth.
• To check if it is too late, subtract days to maturity and a three to four week harvest cushion from your first expected fall frost.
• In hot climates, summer heat can be the cutoff. Large fruited tomatoes may flower but stop setting fruit when average nighttime temperatures rise to around 80 degrees Fahrenheit, according to University of Florida IFAS.
• A fall crop can be the better option in warm regions, with spring and fall windows instead of a summer planting.

When should you plant tomatoes outdoors?

Use three checks, in order. First, frost risk: wait until local spring frost danger has passed. Washington State Extension says do not plant before the frost free date for your area, because spring frost can kill young tomato plants. Second, warmth: aim for nights consistently above 50 degrees Fahrenheit and soil around 60 degrees Fahrenheit. New Hampshire Extension gives the same soil rule: wait until danger of frost has passed and soil temperatures have warmed to about 60 degrees Fahrenheit before setting tomatoes into the garden. Third, variety: match days to maturity to the warm growing season you have left.

Hardening off matters too. Set seedlings outdoors for a few hours each day in filtered light, increase time and sun gradually, and bring them in at night if temperatures fall below 60 degrees Fahrenheit, because below that tomatoes can suffer chilling injury, according to New Hampshire Extension. Washington State gives a similar rule at 50 degrees Fahrenheit: if temperatures drop below 50, keep transplants indoors.

Plant in full sun, at least six hours of direct sun a day, in well drained soil. Space staked or caged plants 18 to 24 inches apart, and install stakes or cages at planting time, not after roots are established.

What is the tomato planting calendar by USDA zone?

These are broad planning windows for outdoor transplants, not guaranteed planting dates, and not USDA issued planting dates. Coastal, inland, and high elevation gardens in the same zone can need different schedules. Local frost dates and actual temperatures take priority.

Regional extension guidance shows why the zone alone is not enough. Washington State recommends planting after the last frost in May or June, while Florida tomato windows vary substantially between its northern, central, and southern regions. For a cool coastal Pacific Northwest garden, a relatively mild winter zone does not automatically mean an early tomato season. Washington State May to June transplant guidance is a more useful regional starting point than a generic warm zone calendar.

Caption: Use the zone window to plan, then use your local frost date, night temperatures, and soil temperature to decide the actual day.

How do you tell when it is too late?

Use this planning rule:

Latest transplant date is approximately your first expected fall frost, minus days to maturity, minus a harvest cushion.

Tomato varieties differ considerably. Some ripen in about 55 days, while others require roughly three months of hot weather, according to New Hampshire Extension. Check whether the variety maturity estimate starts at transplanting or sowing. Extension tables may list these separately.

As a conservative planning example, allow an extra three to four weeks beyond the listed maturity time. That cushion is a planning allowance, not a guarantee, and gives you more opportunity to harvest before cold weather ends production.

For example, with an October 15 first frost estimate:

These dates illustrate the calculation, not universal deadlines. A plant that produces its first ripe tomato just before frost has technically matured, but may deliver very little usable harvest.

If your calculation says you are past the latest date for a long season variety, you are not necessarily out of tomatoes. Switch to an early maturing variety, buy a larger nursery transplant, or plan a fall crop if your climate allows it. In short season locations, Washington State Extension recommends varieties with short growing seasons, less than 75 days, because fruit needs to reach maturity quickly in cooler summer temperatures.

Do seeds need more time than transplants?

Yes. A late planting opportunity for a nursery grown tomato is not necessarily a late opportunity to sow seeds. Indoor seed starting generally adds about six to eight weeks before the plant is ready to move outdoors. When the remaining season is short, established transplants offer a substantial head start.

If you buy seedlings, pick stocky plants with thick, straight stems and bright green leaves, ideally less than six inches tall and as broad as tall, according to New Hampshire Extension. Avoid tall, lanky plants, or plants already flowering or fruiting in a small pot.

What about hot climates, where summer heat is the cutoff?

In warm regions, planting too late in spring can mean flowering coincides with excessive heat rather than autumn frost. University of Florida IFAS notes that large fruited tomatoes may continue flowering but stop setting fruit when average nighttime temperatures rise to around 80 degrees Fahrenheit. Cherry and grape tomatoes are exceptions, and typically perform well through Florida summers.

A fall crop can be the better option. The Florida Vegetable Gardening Guide lists tomato planting windows of:

• North Florida: late March to April, and August.
• Central Florida: January to February, and August to September.
• South Florida: August to February.

Use a local spring and fall calendar in very hot climates, rather than assuming summer is best. Container tomatoes can help here, because you can move a container to a protected location if a late frost or freeze threatens, according to Florida IFAS.

What matters more than your zone?

Before planting, check these four things:

1. Frost risk: wait until local spring frost danger has passed.
2. Warmth: aim for nights consistently above 50 degrees Fahrenheit and soil around 60 degrees Fahrenheit.
3. Variety: match days to maturity to the warm growing season you have left.
4. Regional season: in very hot climates, use a local spring and fall planting calendar rather than assuming summer is best.

Soil pH is also worth a quick check. Tomatoes grow best in slightly acidic soils, pH 6.0 to 6.5 according to Washington State, and 6.2 to 6.8 according to New Hampshire. A soil test is the best way to know your pH and nutrient needs, rather than guessing from a zone map.

How does the Tomato Planting Date Finder work?

The finder turns your frost dates and your variety into dates you can act on, so you do not have to do the subtraction by hand for every variety.

Enter your zone, your last spring frost date, your first fall frost date, and your variety days to maturity. The finder gives you three dates: when to start seeds indoors, when to transplant outdoors, and the last safe transplant date for that variety, with a harvest cushion built in. For example, with an October 15 first frost and a 70 day variety, the last safe transplant date with a four week cushion is around July 9, as in the table above.

That matters because a zone table gives you a month, not a date for your yard. Your frost dates, plus your variety, give you a date you can actually plant by.

Frequently asked questions

Can I plant tomatoes in June?

Sometimes, yes. It depends on your first fall frost and your variety days to maturity. Use the calculation above: first frost, minus days to maturity, minus three to four weeks. If June is before that latest date, and nights and soil are warm, June planting can still work, especially with an early maturing transplant.

What if a late frost hits after planting?

Cover plants with frost cloth, buckets, or row cover in the evening, and remove the cover in the morning once temperatures rise. Do not use plastic directly on leaves. If damage happens, wait a day before judging the plant, prune only clearly dead parts, and watch for new growth. A container plant can be moved indoors for the night.

How warm does soil need to be for tomatoes?

Around 60 degrees Fahrenheit, according to New Hampshire Extension. Check soil temperature with a thermometer in the morning, at root depth, not just air temperature on a warm afternoon.

Which variety should I pick for a short season?

Pick an early maturing variety, ideally under 75 days in cooler short season locations, according to Washington State Extension. Determinate varieties ripen in a shorter window, while indeterminate varieties keep producing until frost, if you have a long enough season to support them.

Can I plant a fall crop of tomatoes?

In warm climates, yes, often as a second crop. Florida, for example, has fall windows in August to September in Central Florida, and August to February in South Florida, according to the Florida Vegetable Gardening Guide. In cooler climates, a fall tomato crop is usually not practical, because nights cool before fruit can ripen.

Do tomatoes need full sun?

Yes, at least six hours of direct sunlight a day, according to Washington State Extension. Tomatoes in shade will grow, but fruit set and ripening will be poor.

Next steps

Use the Tomato Planting Date Finder for your own yard. Enter your frost dates and your variety, and let it give you the start indoors date, the transplant window, and the last safe date.

For the broader vegetable calendar, see When to Plant Vegetables: A Planting Calendar for Every USDA Zone.

For indoor starts, see How to Start Seeds Indoors: A Schedule by Plant Type.