How much sunlight do window box herbs need?
Written by
Michael Sullivan
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Proper sunlight determines whether your window box herbs can make or break the success of your window box. Basil and rosemary require six hours of direct sunlight every day to permit production and growth. Plant these sun-lovers in south-facing locations. If there is not enough light, they will become spindly and produce fewer tasty leaves.
Partial shade suits herbs like mint and parsley perfectly. They thrive with just four hours of morning sunlight followed by afternoon shade. East-facing windows provide the best growing conditions. They are too fine-leaved for excessive sun, which causes them to brown and become unproductive.
Be observant for signs of stress on the plants. The leaves turn yellow due to sunburn caused by excessive sunlight. If the leaves are light green, the plants should have more light. Rotate the boxes every few days for uniformity of light distribution. Use reflective surfaces in the corners of low-light areas to intensify the light.
Full Sun Herbs (6+ hours)
- Basil: Develops best flavor with maximum sunlight
- Rosemary: Produces essential oils under intense light
- Thyme: Flowers abundantly with all-day exposure
Partial Shade Herbs (4-6 hours)
- Mint: Prefers morning sun and afternoon protection
- Parsley: Avoids bolting with filtered afternoon light
- Chives: Tolerates shifting light conditions well
Low Light Tolerant (2-4 hours)
- Lemon Balm: Survives with bright indirect light
- Chervil: Manages in north-facing locations
- Cilantro: Extends harvest with cool shade
Determining the various seasons will necessitate some light adjustments. Summer will bring potential shading plants to protect against the afternoon sun. Winter will have you looking to create maximum exposure on shorter days. Pay attention to sun patterns over the month. Move boxes as the sun's angles change throughout the seasons.
Add supplemental light when necessary. Grow lights work well in dark corners. LED strips operate well at approximately 12-14 hours a day, with the lights positioned 6-8 inches above the plant, to prevent legginess and create a compact bushy plant.
Understanding each herb's light needs guarantees success. Match plants to your available exposure. Monitor and adjust regularly. Your window boxes will overflow with healthy, flavorful herbs throughout the entire season.
Read the full article: 10 Best Window Box Herbs for Your Kitchen
