When to start seeds indoors
Indoor seed-start calendar from your last spring frost: start indoors, harden off, and transplant dates for tomatoes, peppers, brassicas, and more.
Set local frost dates in My Garden to turn these lead times into planning dates. Zone defaults are illustrative examples, not local climate records.
Common indoor start lead times
| Crop | Typical lead time | Seeds |
|---|---|---|
| Onion | 10 weeks before last frost | Shop Seeds Now |
| Pepper | 8 weeks before last frost | Shop Seeds Now |
| Tomato | 6 weeks before last frost | Shop Seeds Now |
| Broccoli | 6 weeks before last frost | Shop Seeds Now |
| Basil | 5 weeks before last frost | Shop Seeds Now |
| Lettuce | 4 weeks before last frost | Shop Seeds Now |
| Cucumber | 3 weeks before last frost | Shop Seeds Now |
Some outbound seed-house links may be affiliate links.
Using last year's packets? Onion, leek, and parsley seed lasts about 1 year and pepper about 2. Check them on the Seed Viability Check and run a paper towel germination test about a month before sowing.
Want to skip the lights? Winter sow in milk jugs outdoors: perennials, hardy flowers, cool crops, and even tomatoes, timed from your last frost.
Find your frost dates | Winter hub
Sources and planning limits
Dates and month ranges are planning examples for U.S. seasons. USDA zones describe winter cold, not frost dates or season length. Use local Extension dates, soil temperature, the forecast, and your seed packet to set actual planting times.