A windowsill seedling has not learned to deal with an exposed patio. Its first outdoor day should not be a full afternoon in strong sun and wind.
Begin with protection
Choose mild weather and a sheltered spot with gentle light. Put seedlings outside for a limited period, then bring them back before conditions become unsuitable. Over subsequent days, extend the time and gradually increase exposure to the conditions the mature plant needs.
The pace depends on weather and species. Hardening off does not make a frost-tender plant frostproof. Watch local forecasts and bring vulnerable seedlings inside when cold, strong wind, or intense heat threatens.
Check the small pots
Tiny root balls can dry quickly outdoors. Check moisture rather than copying the indoor watering routine. Secure trays so they cannot overturn, and keep them off surfaces that become very hot.
Scorched leaves or persistent collapse are reasons to reduce exposure and reassess, not push through a rigid schedule. Once the plants cope with outdoor conditions and planting weather is suitable, move them to their final positions. Keep checking afterward: a larger pot or garden bed changes water movement and gives the roots a different environment to explore.
Further guidance & source notes
- University of Minnesota Extension: Starting seeds indoors
- University of Minnesota Extension: Lighting for indoor plants and starting seeds
These are background resources, not an endorsement of this website. Regional instructions and the needs of your plant take priority.