I ordered grow lights and I never put thought into it until I got bored. But the ones I ordered (found Here) use blue and red LED's for light. What role does the Blue and Red light play for plants?

Also I noticed how it has what the 2 colors do for there plant in the description, I am just not sure it is accurate or if there is more to it...


2 Answers 2


Plants do use red and blue light when they're growing, but usually, uv and far red should be included. The nm level or output of the lights is important too. It's a complicated subject, and some plants may grow better with more red, or more blue; there's also a fair amount of inaccurate information around, but here's a link with some good information, with an embedded link regarding plant pigments and what levels and type of light they absorb http://www.ledgrowlightshq.co.uk/led-grow-lights-what-to-look-for/


On a very general level, blue lights are for vegetative growth, red pushes most plants into reproductive growth when combined with shortening the daylight hours and having strict no interruption of light during the dark phase. This is where green lights come in handy. Similar to the red light in a dark room, the green light is ignored by plants. Suddenly opening a door to have light spill into a dark phase for plants you want to produce flowers and fruit sooner not later will set those plants back for weeks.

This detail about plants and how to understand them better to be able to produce more...flowers is happening because of the laws being changed about marijuana. People are learning more than ever how to grow plants by learning to grow successfully just one plant.

Lots of money involved with this one plant today and the motivation to succeed is very high. No new trend or any special trick has been found to grow plants better than the basic rules to grow all plants.

Mixing the reds and blues of lights is simply reproducing the light spectrum as we know it that plants use the best and most of...More blue is akin to early spring and summer light. More red is akin to late summer and fall lighting. The lighting plants evolved with. We animals evolved with. The lighting that combined with other environmental sensors will tell plants it is time to start making babies via lots of flowers and lots of seed and then either dying (annuals) or go dormant (perennials) and hope the few babies produced that season possibly survived.

If we want our artificial gardens to be more successful, learning about the daylight/diurnal lengths in relation to the darkness is one of those things that makes a huge difference. For those who are growing under artificial light anyway. Plants out of door are regulated by the sun, the local weather, stability of warm seasons and stability of cold seasons.

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