How to use frost dates to plan planting
Frost dates anchor the whole vegetable garden calendar. Your last spring frost is the average date after which damaging frost is unlikely — the green light for tender, warm-season crops. Your first fall frost marks the average end of the season. The window between the two is your growing season.
Most planting instructions are written relative to the last frost: "start indoors 6 weeks before last frost," "direct sow 2 weeks after last frost," and so on. Pick your zone above and the calendar converts those offsets into real dates for the current year — so you can count back from your last frost and know exactly when to sow.
Cool-season crops (lettuce, peas, spinach, kale, broccoli) tolerate light frost and go out early. Warm-season crops (tomatoes, peppers, beans, cucumbers, squash) need warm soil and go out on or after the last frost. Slow growers like peppers and tomatoes get a head start indoors.
Find your USDA hardiness zone
USDA plant hardiness zones divide the country by average annual minimum winter temperature. They're the standard shorthand for "what grows here and when." To find yours, search your ZIP code on the official USDA Plant Hardiness Zone Map. Once you know your zone (for example 6a or 7b), select it above — we use representative zone-average frost dates to build your calendar.
Zones are numbered from coldest (3) to warmest (11), each split into an "a" and "b" half. Lower numbers have later last-frost dates and shorter seasons; higher numbers have long or nearly frost-free seasons.
Cool-season vs warm-season crops
The simplest way to use your last frost date is to sort crops into two groups: cool-season crops that tolerate light frost and go out before the last frost, and frost-tender warm-season crops that wait until after it.
| Cool-season (tolerate light frost; plant before last frost) | Warm-season (frost-tender; plant after last frost) |
|---|---|
| Peas, lettuce, spinach, kale, broccoli, carrots | Tomatoes, peppers, beans, cucumbers, squash, corn, basil |
Frequently asked questions
- When is my last frost date?
- Your last frost date is the average date of the final spring frost for your area, which tracks closely with your USDA zone. Colder, lower-numbered zones have later last frosts. This tool shows the zone-average date; look up your exact zone by ZIP on the USDA map for a closer estimate.
- How many weeks before the last frost should I start seeds?
- It varies by crop. Peppers start indoors about 8 weeks before the last frost and tomatoes about 6 weeks, while many cool-season vegetables are direct-sown several weeks before or just after it. The calendar above lists each vegetable's specific offset.
- What is a USDA hardiness zone?
- A USDA hardiness zone is a region defined by its average annual minimum winter temperature. Zones run from coldest (3) to warmest (11), each split into an "a" and "b" half, and they're the standard shorthand for what grows in your area and when.
- Can I plant before the last frost?
- It depends on the crop. Cool-season crops like peas, lettuce, spinach, and kale tolerate light frost and can go out weeks before the last frost. Warm-season crops like tomatoes, peppers, and beans are frost-tender and should wait until on or after your last frost date.
- What's the difference between the last and first frost date?
- The last (spring) frost is the average date after which damaging frost is unlikely, marking the start of the growing season. The first (fall) frost is the average date the season ends. The window between them is your frost-free growing season.
- How do I find my USDA zone?
- Search your ZIP code on the official USDA Plant Hardiness Zone Map. It returns your zone (for example 6a or 7b), which you can then select above to build your planting calendar.
- Are these dates exact?
- No — they're regional averages by USDA zone. Local microclimates, elevation, nearby water, and each year's weather can shift your actual frost dates by weeks. Treat these as a planning starting point, not a guarantee.