Seed Starting Date Calculator

Enter your last frost date to get indoor sowing, transplant, and direct-sow dates for six common vegetables.

How it works

Enter your average last frost date (your local cooperative extension office publishes one for your area), pick a crop, and the calculator adds or subtracts a fixed number of days from that date. Every crop below has its own offsets for starting seeds indoors, transplanting outdoors, and direct sowing straight into the bed, based on how long that crop typically needs to size up before it can handle the garden.

Worked example: if your last frost date is May 15, tomatoes want to start indoors 42 days before that, which lands on April 3. They then go out into the garden 7 days after last frost, on May 22, once the soil and night temperatures have warmed up. Squash, on the other hand, gets direct sown straight into the bed 14 days after last frost, on May 29, since it doesn't transplant well and grows fast enough to skip the indoor head start.

The table below the calculator lists every crop's dates at once, so you can see your whole spring lineup against a single last frost date and plan seed-starting weekends around it.

FAQ

Where do I find my last frost date?

Search for your state or province's cooperative extension office and "average last frost date," or check a regional planting calendar. It's an average, not a guarantee, so keep an eye on the forecast around that date each year.

Why do tomatoes and peppers need an indoor start but squash doesn't?

Tomatoes and peppers are slow growers that need 6 to 8 weeks of size before they can handle outdoor conditions, so starting them indoors gets a head start on a short growing season. Squash and beans grow fast and dislike having their roots disturbed by transplanting, so they do better sown directly where they'll stay.

What if I have an early cold snap after I've transplanted?

Keep row cover or old sheets on hand for the first couple of weeks after transplanting. These dates are averages built on typical years, not a promise that frost is finished for good.

Can I use this for a fall or second planting?

This tool is built around spring planting from a last frost date. For a fall crop, you'd count backward from your average first fall frost instead, and the offsets for direct-sow crops like lettuce and beans are a reasonable starting point for that math too.

For the indoor-start crops, see how to start seeds indoors and how to harden off seedlings before they go out. For the bigger picture across a whole season, see a first-year vegetable garden plan, month by month.