Can seedlings be hardened off in shady areas?
Written by
Julia Anderson
Reviewed by
Prof. Martin Thorne, Ph.D.The influence of shade on seedling protection during the hardening off process cannot be overstated. It affords essential protection to tender seedling leaves during their first critical days in the field. Start the plants out in full shade or dappled light. It will greatly reduce the chance of leaf scorch and also help the seedlings to acclimate gradually. I always start them out in either the north side of the house or behind some trees for their first exposure.
Natural Shade Locations
- Use north-facing building walls for consistent morning shade
- Position under deciduous trees for dappled light patterns
- Avoid dense evergreen shade blocking all sunlight
Artificial Shade Solutions
- Install 30-40% shade cloth on PVC hoops
- Use lattice panels for adjustable light filtration
- Repurpose window screens as temporary shade covers
Duration Management
- Maintain full shade for first 2-3 days
- Introduce 30 minutes of morning sun on day 4
- Increase sun exposure gradually over 7 days
Shade serves other purposes in addition to sun protection. Shade reduces wind exposure, which slows down moisture loss. Temperatures in the shade are more stable. The plants actually develop a thicker cuticle since they are in filtered light. I watch the UV index and adjust the shade accordingly. Never full shade, as this will stop growth.
Even under cloudy conditions, shade management is a must. UV rays penetrate through clouds with approximately 80% of their original intensity. Therefore, we should use shade cloth even on overcast days. I learned this lesson when seedlings were scorched on cloudy days. Check your weather apps and review the UV index readings daily.
Start outside in deep shade. After about a week, gradually expose a little to the morning sun. On day one, keep away from all midday sun. A little extra sun each day is good (30 to 60 minutes). Increase gradually. Watch for curled leaves and discoloration of foliage. If this occurs, take immediate action, reducing sun exposure.
Read the full article: The Complete Guide to Hardening Off Seedlings
