400w "mh"~veg "hps"~flower lighting height

[420atsk]

Im running 1 400w mh-for veg & hps for flower in a 4' x 4' x 7' tent that i made for cheap but its great how high could i run my light?
I had been told 15"~24" ive had it about 12" its doing great but if i was to raise it up to prob to 20" im not 100% just raised it up all the cola's get more direct/reflected light but is the lumen still good enough to produce dense bud's i have 3 main plants 2 bigger ones 1 that was from a seed. "ive been fine haven't had a prob yet from a seed for the people that wont touch a seed" anyways it is getting a little to big to have it at 12" and reach everything it should.imp:

420atsk Reviewed by 420atsk on 01-31-2011. 400w "mh"~veg "hps"~flower lighting height Im running 1 400w mh-for veg & hps for flower in a 4' x 4' x 7' tent that i made for cheap but its great how high could i run my light? I had been told 15"~24" ive had it about 12" its doing great but if i was to raise it up to prob to 20" im not 100% just raised it up all the cola's get more direct/reflected light but is the lumen still good enough to produce dense bud's i have 3 main plants 2 bigger ones 1 that was from a seed. "ive been fine haven't had a prob yet from a seed for the Rating: 5

[420atsk]

here are a few shots after i shaved them a lil

[greg1317]

I have found that its best to keep the light about 24in above the plant in the first week (when the plants are about 2in high or the first week you transplant clones) Then 12-14in above your plants during the rest of veg with the top of your tallest plant being 12in away. You want to try to keep your canopy as even as possible hopefully with just a few inches difference in your plants. During flower I usually like to put the light at around 10in and let it grow to 9in then move it again. It also depends on if your light is air cooled and what the temperature of your canopy is when you have your light that close. If you had a digital thermometer with a probe hanging over the canopy you could see what the temperature is right above the canopy when you have your light at a given distance. You want to keep the light as close as possible without burning the plants or causing them to wilt from heat. Its optimal to have you canopy remain at around 72-75*F but it can vary from there. I wouldn't recommend temps below 60* or above 90*. If you can keep your temps in the 70s at all times that is optimal especially during flower. Night temps can be 10* lower than day temps without any problems. However, my friend has grown during the summer here in CA when its over 100*F during the day and his box got to 100* sometimes. Even with those conditions his buds still turned out dank. So its definitely possible to grow dank buds in less than perfect conditions. Hope that helps.

[greg1317]

I wasn't really clear about this before so I thought I should say it. You want to keep the light as close as possible but you also want to keep the light far enough away that the plants get a good spread. Thats why i recommended the heights that I did because they give you that spread you need while keeping your light close.

[420atsk]

ok thanks i have an open reflector and my temps never go under 65 and not over 85ish i think is what ive seen it at i ha vent had a prob with the plants burning its just other cola's are not lit up but im thinking if they grew that way back there they shouldn't hurt any production on the top cola's im kinda done moving and cutting because i should be flowering soon but when i flower keep the light as close as possible and DONT trim for the cola's to get light after i have click to 12/12 right

[Dutch Pimp]

ok thanks i have an open reflector and my temps never go under 65 and not over 85ish i think is what ive seen it at i ha vent had a prob with the plants burning its just other cola's are not lit up but im thinking if they grew that way back there they shouldn't hurt any production on the top cola's im kinda done moving and cutting because i should be flowering soon but when i flower keep the light as close as possible and DONT trim for the cola's to get light after i have click to 12/12 right

vegging with MH is best...but, too far away is better than too close.
UV rays are strong with MH light. If you want to know how strong?...stick your hand under it for 5 minutes...
... & wait for the pain in two days....just kidding...don't do that!

If you burn the tops...it takes a long time to recover & not all reflectors are created equal.

[420atsk]

i just raised it to about 15in above the top of my smaller plant it been doing good i also cut a bunch of growth that would have nugged because that book said to so im trying it and it is reflecting more to the back just look's naked and so you know i didnt cut it all out i did about 2/3 more towards the main stem and up each branching off point a lil

I also just went 12/12 to flower so i will update on that Now im going to leave my MH for what 2 weeks and then switch to my HPS or what have some people dont thats works and if you have pics or videos that would help alot more Thanks 420:rastasmoke:

[khyberkitsune]

I'd personally stick with the MH all the way through. That's just me, though.

[greg1317]

I'd personally stick with the MH all the way through. That's just me, though.

In my opinion that's a really bad idea. Mh doesn't give off the proper spectrum of light that the plant needs in flower. When flowering the plants need more of a red spectrum and mh provides a more blue spectrum of light. Mh is great for veg and keeps your internodal length short. I would use the mh for the first two weeks of flower then switch to an hps. That is the way all the pro growers do it and I would recommend that way myself. It is possible to veg with hps and I've done it but I wouldn't flower with mh.

[Dutch Pimp]

I'd personally stick with the MH all the way through. That's just me, though.

I have started weaning myself from HPS lighting.
I only used it during flowering weeks #5 though #8. and I was disappointed in bud growth...but, going back to full CMH lighting will help save some yield & quality....currently at 9+ weeks.

Switching back to (C)MH full time, next grow...:thumbsup: