Seed starting timeline calculator
Enter your average last spring frost date. Get a personalized timeline of when to start each vegetable and flower indoors, when to direct sow outdoors, and when to transplant. Based on Cornell, Penn State, and Johnny's Selected Seeds growing guides.
Free · No signup · Based on Extension recommendationsDon't know it? Use the frost date lookup tool first.
How to use this
Every crop has an ideal window measured backwards from your last frost date. Cool-season crops can be direct-sown outside before the last frost; warm-season crops must wait until after. Plants started indoors give you a 4-8 week head start, which is critical for warm-season crops in zones 5-7 where the frost-free season is only 130-160 days.
The dates below assume you have a heated indoor space at 65-75F. A seedling heat mat (78-82F at the soil) doubles germination rates for warm-season crops (pepper, tomato, eggplant, basil) per Cornell Cooperative Extension.
For light, modern T5 LED shop lights 2-4 inches above the seedlings beat "grow lights" at a fraction of the cost.