What lighting setup works for indoor herbs?
Written by
Paul Reynolds
Reviewed by
Prof. Martin Thorne, Ph.D.More than any other factor, lighting will determine the success of your indoor herb garden. Indoor herb plants require sufficient light intensity and duration to thrive; without it, they may become leggy and weak. Knowing your choices will help you understand how to achieve success, avoid disappointment, and avoid wasting time and effort.
Windows exposed to the south receive the most natural light. South-facing windows receive the most direct sunlight, approximately 6 to 8 hours per day. This is perfect for Mediterranean herbs, such as rosemary. My rosemary grows in an area near a south-facing window. Ideally, place the plants close to the glass and rotate the pots every week. You can also use mirrors to help meet the plants' light needs.
Essential in darker spaces, full-spectrum LED lights provide customizable intensity and duration. My basil grows significantly bushier under LEDs compared to natural light. When in doubt, opt for lights in the blue spectrum to promote compact growth and yield higher-quality plants. Place lights 6-12 inches above the top of the plant canopy for optimal light use.
Positioning
- South windows: 0-3 feet from glass
- LED lights: 6-12 inches above plants
- Rotate plants 90° every 3 days
- Avoid direct contact with cold windows
Timing
- Mediterranean herbs: 12-14 hours daily
- Mint/parsley: 10-12 hours sufficient
- Use automatic timers for consistency
- Mimic natural seasonal light changes
Intensity Control
- Measure with lux meter app (20,000 lux ideal)
- Adjust LED height for intensity changes
- Use sheer curtains to diffuse strong sunlight
- Supplement natural light with LEDs in winter
Automate your lights with timers for perfect regularity. Set them for a 14-hour cycle for Mediterranean herbs. My setup turns on at dawn, trying to imitate nature. Consistency prevents stress and increases oil production in culinary herbs. If the light is consistent, you will better see flavor development.
Observe your plant responses for necessary adjustment of your setup. Having long internodes indicates that the plant is not receiving enough light intensity. Having pale leaves indicates that there is too much direct sunlight. I had casual stress with my oregano until I moved it back from the window. Look for these signals, and change accordingly.
Seasonal adjustments preserve productive conditions in all seasons. Light from the winter months weakens and requires longer times. Each season, my LED system makes up for the shorter days. Summer requires location changes away from the hot windows. Adjust your approach and practice as the day length changes during the year.
Read the full article: 7 Essential Indoor Herb Garden Secrets
