Seed starting calculator
Your last frost date is the anchor. This counts back the right number of weeks for each crop that's normally started indoors.
Pick a location or date to see your indoor sowing schedule.
How this is calculated
Sow-indoors date = last spring frost − the crop’s recommended head-start (6–8 weeks for tomatoes, 8–10 for peppers and onions, 3 for cucumbers and squash). “Move outdoors” is a ±1 week window around the crop’s safe transplant date relative to that same frost date. Warm crops such as pepper and eggplant only go out once nights are reliably above 55 °F.
Common questions
What if I don't know my exact last frost date?
Pick your state or ZIP in the planting calendar - it looks up the average last frost for your area from NOAA data, which this calculator then uses automatically.
Why do some crops on my list show no indoor start date?
Crops that transplant poorly or grow fast enough from a direct sowing (most root vegetables, beans, corn) are normally sown straight into the garden rather than started indoors, so they won't appear here.
I started seeds late - what should I do?
Seedlings started a couple of weeks late usually still catch up fine; if you're more than 3-4 weeks behind for a long-season crop like peppers, consider buying transplants instead so you don't lose too much of the growing season.