Seed Starting Date Calculator — When to Start Seeds Indoors
Enter the date you plan to transplant seedlings into the garden and the number of weeks the seeds should be started indoors before that date. The calculator gives you the date to sow your seeds. Use the weeks-before recommendation from your seed packet.
What this calculator determines
It calculates the date to start seeds indoors by subtracting a number of weeks from your target transplant date.
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Frost Date Planting Planner
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Fall Garden Planting Calculator
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Days to Harvest Calculator
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Succession Planting Calculator
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Examples
Transplant May 15, start 6 weeks before
Transplant May 15, 6 weeks before
Calculation
- 6 weeks = 42 days
- May 15 − 42 days = April 3
Start seeds indoors: April 3
Assumptions & Conventions
- Date arithmetic
- Seed-start date = transplant date − (weeks × 7 days), counted on the calendar.
- Weeks before
- Use the weeks-before recommendation from your seed packet; there is no universal lead time.
- Frost date
- Does not look up your local frost date — you choose the transplant date based on your own planning.