Pick a plant and we'll work out when to start seeds indoors, when to transplant or sow outdoors, and roughly when to harvest, based on your area's average frost dates.
About this tool: frost dates and start timesRelated Tools
Draw your beds to scale, place plants at their spacing, and get planting dates for each crop.
Open the plannerGrowing degree days for your location compared with an average year, for timing crops and pests.
Open the calculatorWhich plants grow well together and which to keep apart.
Open the guideEnter your soil test results and get an amendment plan.
Open the calculatorThe published last-frost date is the one frost has passed by in half of years, so frost still comes after it one year in two. A 10 percent date is much safer for tender crops.
Weeks from sowing to setting out:
| Crop | Sow indoors |
|---|---|
| Onions and leeks | 8 to 10 weeks |
| Peppers and aubergines | 8 to 10 weeks |
| Tomatoes | 6 to 8 weeks |
| Brassicas | 4 to 6 weeks |
| Cucumbers and squash | 3 to 4 weeks |
Sowing earlier produces root-bound seedlings, which are routinely outgrown by ones sown weeks later. Soil temperature beats the calendar: beans need 55 °F soil and squash 60 °F to sprout.
Tomatoes root along a buried stem, so plant leggy ones deep. Harden everything off over two weeks.
For transplanted crops the packet counts from transplanting, so a 75-day tomato is really 75 plus its weeks as a seedling. Add two more weeks for autumn crops, as everything slows with the daylight.
Sowing weeks: UNH Extension, with Minnesota for flowers. Frost classes, days to harvest and soil temperatures: Colorado State. Fall dates: Nebraska. Garlic: Minnesota. Other numbers are Bizon estimates (sources).