Turn one frost date into a crop schedule you can put on a calendar today.
Pick a crop and last frost date to get indoor sowing, hardening-off, and transplant windows.
What this tool decides
Decides the practical indoor sow, harden-off, transplant, and direct-sow windows from one frost date.
Step 1
Set your inputs
Step 2
Calculate the number
Step 3
Read the plan
Timing inputs
Diagnostic panel
Start indoors
Mar 18
Tomato usually needs about 6 weeks indoors before transplanting.
Schedule lane
Start indoors
Mar 18
6 weeks before transplant
Harden off
Apr 22
Begin outdoor exposure
Transplant
Apr 29
After frost risk eases
Direct sow
Skip
Use transplants for this crop
Read the plan
What it means
The result shows the sequence, not just one date: start indoors, harden off, transplant, and direct sow when the crop allows it.
Next action
Write the dates on your calendar, then check spacing so the number of starts matches the bed you actually have.
Risk note
Starting too early creates leggy seedlings that stall outside; starting too late shortens the harvest window.
Common mistakes
Warm crops, herbs, and cool-season crops need different lead times.
Indoor seedlings need a transition week before full sun, wind, and outdoor temperature swings.
Field note
Seed starting works best when you start with the outdoor planting window and count backward. After this tool gives you dates, use the Care Calendar to sanity-check whether that crop belongs in the current month for your zone.
The presets cover common vegetable and herb timing, but crop choice still matters. If you are deciding what to grow before you calculate dates, filter candidates in the Plant Finder so the schedule matches your light, water, and climate limits.