Seed Starting Calculator

Know exactly when to start seeds

Pick a crop and your key date. Plantometry counts back from frost or your transplant date to tell you when to sow indoors, when to move plants out, and when direct sowing is an option.

Crop

Seed-starting timing is crop-specific, so a crop is required here.

Target transplant date

When you plan to move plants outdoors.

Start indoors — weeks before

wks

Default for Lettuce: 3 weeks. Override if you like.

Your sowing timeline

Start seeds indoors
July 19, 2026
Sow in trays about 3 weeks before transplanting.
Transplant outdoors
August 9, 2026
cool-season crop; transplant timing depends on season
Direct sow (alternative)
direct sow in cool soil; type-dependent density