Gels for color

I used to work in a club where they use thin pieces of colored plastic called gels to change the color of the stage lights. Do those gels actually change the color spectrum? Do they make the lights more useful to the plant? I was thinking of using blue gels for vegetative and red for flowering.

The gels don’t convert white light to another color. They filter out all the other colors except for the one that passes through. The filters limit the light the plants receive to a single color. They are not receiving as much total useable light as they would without the filter so they will grow slower and yield less.

Readers with grow questions (or answers) should send them to Ed at: Ask Ed, PMB 147, 530 Divisadero St., San Francisco, California 94117, USA. You can also email Ed at [email protected], and send queries via his websites at All featured questions will be rewarded with a copy of Ed’s new book, Best of Ask Ed: Your Marijuana Questions Answered. Sorry, Ed cannot send personal replies to your questions.