Can You Grow Plants Using Only Red Light?

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.

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