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Seed Starting Calculator

Calculate when to start seeds indoors from your last frost date and the number of weeks the seed packet recommends.

Last frost date

Start indoors (weeks before last frost)

Transplant (weeks after last frost, negative = before)

How to use it

Enter the last frost date.
Enter the weeks from the seed packet.

How it works

Sow date = last frost − weeks indoors (+ transplant offset). Harden seedlings off for 7-10 days before transplanting.

FAQ

When should I start tomato seeds?

About 6-8 weeks before your last frost date.

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Free calculator by FrostWise