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Calcimator

Seed Starting Calculator

Find out when to start seeds indoors, when to transplant, and when to expect your harvest based on plant type and last frost date.

Inputs

weeks

Results

Start Seeds Indoors

Mar 19

Transplant OutdoorsMay 14
Expected HarvestJul 23
Days to Germinate7 days
Ideal Soil Temp65-85°F
Days to Harvest (from transplant)70 days
Total Growing Days126 days

Start Seeds Indoors

Mar 19

How to Use This Calculator
  1. Start by filling in the input fields below. Results update instantly as you type, so you can experiment with different values to see how they affect the outcome.
  2. Plant Type — Select the type of plant to determine transplant timing and harvest estimates. Choose from: Tomatoes, Peppers, Lettuce / Greens, Squash / Zucchini, Herbs (basil, parsley), Melons / Watermelon, Broccoli / Cabbage, Flowers (annual). default: 1.
  3. Last Frost Date (Day of Year) — Day of the year for your average last spring frost. Apr 30 = 120, May 15 = 135. Check your USDA zone. Accepts values from 1 to 365 (default: 120).
  4. Weeks to Start Indoors — Number of weeks to grow seedlings indoors before transplanting. Accepts values from 2 weeks to 16 weeks (default: 6 weeks).
  5. Once all inputs are set, review your results in the Results panel. Here's what each output means:
  6. Start Seeds Indoors — your calculated result. This is the primary result of this calculator.
  7. Transplant Outdoors — your calculated result.
  8. Expected Harvest — your calculated result.
  9. Days to Germinate — shown as a numeric value.
  10. Ideal Soil Temp — your calculated result.
  11. Days to Harvest (from transplant) — shown as a numeric value.
  12. Total Growing Days — shown as a numeric value.
  13. Explore the related calculators below if you need deeper analysis or want to approach this topic from a different angle.
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