How do I find my last frost date?

Your last frost date is the average date in spring when overnight temperatures last drop to 32°F (0°C). Look it up by city using a frost date resource or the companion Frost Date Lookup tool on this site. Most US gardeners fall between March 1 and May 15.

What does "weeks before last frost" mean?

Seed packets list how many weeks before the last frost you should start seeds indoors. A value of 6–8 weeks means you sow indoors 6 to 8 weeks before your last frost date so seedlings are ready to transplant when outdoor conditions are safe.

Can I transplant on the last frost date?

For frost-tender crops like tomatoes and basil, wait 1–2 weeks after your last frost date to account for late cold snaps. The transplant dates shown here add a 1-week safety buffer by default. Cold-tolerant crops like broccoli and cabbage can go out at or before the last frost date.

What if I start seeds too early?

Starting too early produces large, root-bound, or leggy seedlings that are harder to transplant and more susceptible to transplant shock. Stick to the recommended lead times for each crop.

Do all seeds need indoor starting?

No. Root crops (carrots, beets, radishes) and fast growers (beans, squash, cucumbers) are best direct-sown outdoors. The crops listed in this calculator are those that benefit from an indoor head start.

Seed Starting Date Calculator

Name: Seed Starting Date Calculator
Availability: InStock
Author: Nham Vu

Enter your last frost date and pick a crop to get the exact indoor seed starting date and safe outdoor transplant date.

Your Frost Date

Last spring frost date

Don't know it? Use the Frost Date Lookup tool.

Transplant safety buffer

Add crops to your schedule

Custom crop

weeks before frost

No schedule yet

Set your last frost date and add at least one crop to see dates.

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Summary

Enter your last frost date and pick a crop to get the exact indoor seed starting date and safe outdoor transplant date.

How it works

Enter your average last spring frost date.
Select a crop from the list or add a custom lead time.
The calculator counts backward to give your indoor start date.
It also shows the earliest safe outdoor transplant date.
Add multiple crops to build a full starting schedule.

Use cases

Plan exactly when to sow tomatoes, peppers, and eggplant indoors.
Avoid leggy seedlings by not starting too early.
Coordinate greenhouse space when starting many crops.
Build a printable seed-starting calendar for the season.
Confirm whether a crop has enough frost-free days to reach harvest.
Schedule successive plantings to spread out transplant workload.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu