Can You Grow Plants Using Only Red Light?

December 15, 2018

When you grow plants under only red light, they can put on additional leafy growth, or biomass. This is good for certain crops, such as lettuce. But as plants develop more leaves and other structures, they may not transpire properly or they can stretch, get too tall, or develop oedema (leaf blisters—a common issue in tomatoes grown under only red light) or other problems.

Oedema has become an issue on these pepper plants grown exclusively under high-pressure sodium (HPS) lamps.
PC: Leslie F. Halleck

If you grow your plants under only red light for too long, chlorophyll production can stop altogether, causing photosynthesis to cease.

Gardening Under Lights Book

Back to top

Tips in your inbox


Sign up for my monthly E-Newsletter for botanical business news and tidbits for plant and gardening lovers!