Work backward from a transplant date
A seed-starting date is a calendar subtraction from a chosen transplant date. It does not determine when frost will end or when soil will be ready. The lead time must belong to the crop and variety being started.
Measure and calculate
- Choose a transplant date suitable for your location and growing conditions.
- Enter the number of weeks indoors for the selected crop and variety.
- Count backward by seven calendar days per week and review the resulting sowing date.
Sowing date = transplant date − 7 × lead weeks.
A worked example
- Inputs
- The example tomato transplant date is May 15, 2027, with six weeks indoors.
- Calculation
Six weeks is 42 days. May 15, 2027 minus 42 days is April 3, 2027.- Result
- 2027-04-03 calendar date
The initial date result is 2027-04-03. Replace the transplant date before treating it as your planting schedule; no local forecast is fetched.
Read the result
| Output or check | What it means for your project |
|---|---|
| Calendar sowing date | The result counts backward from the transplant date by seven days per lead week. It can cross month and year boundaries. |
| Local planting decision | The preset date and lead time are examples. Replace them with values appropriate to the location, crop and variety; the tool does not fetch frost dates or weather. |
Common questions
Is May 15 the right transplant date for my garden?
It is an example only. Local weather, site conditions, growing method and crop requirements determine a suitable date.
Why does the answer change across month boundaries?
The calculator subtracts calendar days, not a fixed month fraction. Weeks can cross months and years naturally.