Hardening off transplants without losing them — print version.
Press Cmd/Ctrl + P, then choose “Save as PDF.”
SUS Farms · Utah Gardening
Hardening off transplants without losing them
season · beginner · ~4 min read
Plants grown indoors under LED lights and in still air have soft leaves with thin cuticles, no UV protection, and weak stems. Plant them straight into a Utah May afternoon and they'll burn, sunscald, or snap in the wind by sundown. The fix is a 7–10 day ramp.
The week-long protocol
Day 1: 1 hour in deep shade. Day 2: 2 hours, mostly shade. Day 3: 3 hours, some morning sun. Day 4: 4 hours, half sun. Day 5: 5 hours, mostly sun. Day 6: 6 hours including midday. Day 7: All day outside, transplant in the evening.
Skip days that are wrong
Wind above 15 mph or temps below 50°F = pause for the day. Hardening-off is about gradual exposure, not calendar progress.
Wind matters as much as sun
A small fan blowing across seedlings indoors for the last 2 weeks before transplant builds stronger stems. Most beginners forget the wind component entirely.
Transplant in the evening
Set out plants 2 hours before sunset on a windless day, water them in deeply, and let them settle through cool night air. Mid-morning transplant under full sun = wilted, stunted plants for weeks.