Hardening Off: A 7-Day Schedule
Hardening off acclimates indoor seedlings to outdoor conditions over 7–10 days. Skipping it causes sunscald, wind damage, and transplant shock.
Indoor seedlings have thin leaves. Direct sun and wind damage them.
The Schedule
| Day | Time Outside | Conditions |
|---|---|---|
| 1 | 1 hour | Shade |
| 2 | 2 hours | Shade |
| 3 | 3 hours | Morning sun |
| 4 | 4 hours | Morning sun |
| 5 | 5 hours | Morning + some afternoon |
| 6 | 6 hours | Most of day |
| 7 | Overnight | If above 50°F |
Rules
- Start in shade. Direct sun burns.
- Bring in at night. Until day 7.
- Water before. Dry seedlings stress more.
- Shelter from wind. Wind dries and breaks stems.
Common Questions
Can I skip it? No. You’ll lose seedlings.
What if I don’t have time? Minimum 4 days. Still better than nothing.
Can I harden off in a cold frame? Yes. Easier.
What about cloudy days? Good for hardening. Less stress.
What if it rains? Skip that day. Resume next.
What if leaves turn white? Sunscald. Move to shade. Wait.