Seed Starting and Transplant Offset Calendar
Calculate sowing, hardening and scenario harvest dates from a user-supplied transplant reference date and crop durations.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Subtract each entered indoor growing duration and hardening duration from the common transplant date, then add the entered transplant-to-harvest duration.
Sow date=transplant−round(weeks×7) days; hardening start=transplant−hardening days
Worked example
A May 1, 2027 transplant reference with six indoor weeks gives a March 20 sow date. Seven hardening days start April 24. Sixty days after transplant is June 30.
Assumptions and input details
Dates are entered scenarios, not local frost dates or crop recommendations. Gregorian years 1900–2199; calculated dates must stay in that range. Weeks convert to nearest whole day with half ties upward. Hardening cannot start before the modeled sowing date. Maturity days here start at transplant, not sowing. Weather, germination, plant readiness, local calendars and actual harvest are not predicted. Up to 50 crop rows.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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