When to Start Seeds Indoors for March 15 Last Frost (6 Weeks)?
With a March 15 last frost and 6 weeks lead time, you should start seeds indoors around February 1.
How to use this tool
- Enter your average last spring frost date.
- Enter the number of weeks before transplanting to start seeds indoors (from the seed packet).
- The calculator returns the date you should sow seeds indoors.
Zone 7 gardeners can start transplants earlier — enter your March 15 frost date with a 6-week lead to find your indoor sow date.
Frequently asked questions
- When should I start seeds indoors?
- Most vegetables should be started 6–10 weeks before your last frost date. Tomatoes and peppers need 8–10 weeks; broccoli and cabbage need 4–6 weeks. Always check the seed packet.
- How do I find my last frost date?
- Enter your zip code on the USDA Plant Hardiness Zone Map website or ask your local cooperative extension service for the average last frost date in your area.