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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
How to Use This Calculator
  1. Select your plant type (tomatoes, peppers, lettuce, squash, herbs, melons, broccoli, or annual flowers).
  2. Enter your last spring frost date as a day of the year — for example, April 30 = day 120, May 15 = day 135.
  3. Enter the number of weeks you plan to grow seedlings indoors before transplanting (typically 6-8 weeks for tomatoes).
  4. Review the Start Seeds Indoors date to know exactly when to sow your seeds.
  5. Note the Transplant Outdoors date and Expected Harvest date to plan your entire season.
  6. Use the Ideal Soil Temperature and Days to Germinate to optimize your germination setup.
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