Enter your average last spring frost date and pick a crop. You’ll get the window for sowing seeds indoors and the window for planting them out.
When to start seeds indoors
Enter a valid date, for example 04/20.
Sow seeds indoorsFeb 23 – Mar 9
Transplant outdoorsApr 27 – May 4
Sow indoorsTransplant
FebMarAprMayJun
Frost riskFrost-free seasonSow indoorsTransplant
Wait until nights stay above 50°F before planting out.
See dates for every crop
Crop
Sow indoors
Transplant
Tomatoes
Feb 23 – Mar 9
Apr 27 – May 4
Peppers
Feb 9 – Feb 23
May 4 – May 11
Eggplant
Feb 9 – Feb 23
May 4 – May 11
Basil
Mar 9 – Mar 16
Apr 27 – May 4
Onions (from seed)
Jan 26 – Feb 9
Mar 23 – Apr 6
Cucumbers
Mar 30 – Apr 6
Apr 27 – May 4
Summer squash and zucchini
Mar 30 – Apr 6
Apr 27 – May 4
How this calculator works
Seed packets give starting times as a number of weeks before your average last spring frost. The calculator counts back from the date you enter, using typical ranges for each crop. Tomatoes, for example, are usually started 6 to 8 weeks before the last frost and moved outside 1 to 2 weeks after it.
A frost date is an average. In half of all years the last frost comes later, so tender crops like tomatoes, peppers and basil go out after the date, once the soil has warmed. Hardier crops such as onions can be planted a few weeks before it.
Getting the timing right
Count from the start of the sowing window if you grow under strong lights, and from the end if you rely on a sunny window.
Check the 10-day forecast before transplanting. A late cold snap matters more than the calendar.
Harden off seedlings for about a week before they go in the ground.
Frequently asked questions
How do I find my last frost date?
Use our Frost Dates by ZIP Code tool, which uses NOAA records from the weather station nearest to you. Your local Cooperative Extension office also publishes frost dates for your area.
Is it bad to start seeds too early?
Yes. Seedlings kept indoors too long get leggy and root-bound, and they often grow more slowly after transplanting than younger plants. Starting within the window shown gives you sturdy plants at the right size.
What does "weeks before last frost" mean?
Seed packets count backward from your average last spring frost. "Start 6 to 8 weeks before last frost" with an April 20 frost date means sowing indoors between February 23 and March 9.
Do I need to harden off seedlings before transplanting?
Yes. Over 7 to 10 days, set seedlings outside for a few hours a day in a sheltered spot and increase the time gradually. This toughens them against sun, wind and cooler nights.
A day-by-day schedule for moving indoor seedlings outside without sunscald, wind damage or transplant shock, plus signs your plants are ready to plant.
How to tell when frost is coming and how to protect tender plants with covers, water and cloches, plus which vegetables need protection and which don’t.
Plant tomatoes outside 1 to 2 weeks after your last frost, once nights stay above 50°F and the soil has warmed to 60°F. Here is how to time it for your area.