Quote Originally Posted by Vancefish
From what I've read(in the lighting section of this forum).

MH put out a higher blue spectrum and are best for Vegitative growth. There is also some belief that the UV put out by these produces more resins.

HPS put out a higher RED spectrum thus simulating the Fall sun. Which in turn is needed to flower.

It has been said running both the entire time is best. However next best is MH to grow and HPS to flower
This whole thread is a mess. What I said above and quoted myself on is what almost ALL of the lighting posts say. My only mistake was saying RED was NEEDED to flower. What I should have said was RED is useful to the plant during flower, not NEEDED.

MH to grow the plant. (uses blue spectrum for growth)

HPS to flower the plant. (uses RED spectrum for best flowering)

MH AND HPS for all stages (uses Blue to grow, uses red during flower and SOME PEOPLE SAY,... The UV in the MH CAN (supposedly) create more resins during flower, which is normally missing in a HPS. THUS this (RUNNING BOTH DURING FLOWER) is considered the best method.

Quote Originally Posted by twitch
what i was asking is what is the disadvantage of using an hps the whole way
through? i mean i ma getting an MH today anyway i was just curious as to why
i see these people with the monster grows that they use hps on there veg
stage too.... i was kinda hoping for a response from someone that uses the
hps for veg, no offence to the people that put their :twocents: in
oh and i dont think a MH can help with resin production since all the resin
production i have seen comes in the flower stage
And THIS is exactly the info I was trying to get across.

You can (and many people do) use HPS for ALL stages.

The reason HPS is not "prefered" during the growth stages is the plant uses/needs far more BLUE light to grow then RED. The only disadvantage to using MH to grow is the lack of RED during flower and the only disadvantage to HPS for growing is the shortage of blue during vegitative.

This plant produces RESINS to protect itself from UV (sunburn). Thus SOME PEOPLE SAY using the HPS to get your RED spectrum (for bigger flowers) AND a MH at the same time (for UV) will produce higher resin consentration. I personally DO NOT know that it's true. It does make sence to me if this really is the purpose of the resins.

This being re-stated I repeat,... The disadvantage to HPS for all stages is the LACK OF BLUE LIGHT in most HPS bulbs for great vegitative growth!

And YES Joel HPS IS considered best for flowering. MH is best for VEG because of the BLUE! I think you reversed it there.

Sorry this is getting so confusing. I said RED was NEEDED, and that seems to have been taken to say it wouldn't flower at all without RED. This is NOT what I meant. I just meant to say RED is advantagous during flower. However the increased BLUE from a MH is better for veg., when RED is not really needed at all.