Auto Lights, spectrum question?

I have 4 new autos going.
Two are 1-1/2 weeks into flower and two are 1 week into veg.
I’ve read where using both red and blue spectrum will increase the grow and then I have heard that using red as well as blue during veg will stunt the growth and using both in flower will limit harvest by causing buds to be leafy.???
I want to get the most (‘ya think’) out of both phases.
thanks for the help

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It depends on how unbalanced the spectrum is, what you’re trying to use for lighting. I have almost broad spectrum light but it’s LED.
I’m guessing you’re referring to hps and MH?

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Thanks for the reply I have the (2) 1200 W king LED’s That have separate veg blue and bloom red switches or I can turn them both on


I would recommend to turn them both on.


After plant gets 4 or 5 full Sets of leafs. Turn both switches on Blue spectrum and Red Spectrum.


Blue light for a plant promotes more plant mass like nodes and leaves. Heavy blue lights will make a plant grow more squaty and compact.

Red light promotes more stem growth resulting in longer node spacing and leggy plants. Red light also promotes bud development throughout flower. However far blue/UV light at the end of flower helps terpine development.

Ideally you want a 3500k to 4000k for vegetative growth and more of a 3000k for the flowering cycle if you have the means to do so.