basic questions

[GetstheShit]

Before I begin a project, I like to have all of ym basic planned out, and as many contingencies as I am able prepared for.

Thus, while the basic plan for my grow is taking shape, I have some questions that may impact that pretty heavily.

I was planning on running a MH lamp and a HPS lamp in the same area for both veg and flower. However, I was wondering, if maybe I should substitute a pair of CMH's, or one larger CMH for both, or maybe run the CMH instead of the regular MH??

Also, with a pair of air cooled 250W lamps, how far above a scrog canopy should I put them. I am looking at a 2.5' x 2' grow area, and wanted to run about 100W / SF. I don't want to burn my precious ladies, so erring on the side of caution would be a better idea, but I want to be sure there's more than plenty of light to go around.

 

[MJane'spoontang]

Hey, what's up, Getshit?

Now I am by no means an expert, and I have yet to start my first organic run but I figure i might be able to help you out.

I say if you have yet to buy that MH ballast, don't bother. I'd say buy the HPS ballast and run a CMH for both veg and flower, it has a much more complete spectrum for the plants at both stages of growth.

As for the wattage it all depends on your space. Correct me if i'm wrong, but i believe CMH's only come in 250 or 400 W so if you wanted you could run 2 250W and have a total of 500W but you would still not get the penetration as a 400W so you'd be looking at having a larger number of smaller plants. It's just a matter of preference and growing space (I run a 250W CMH for veg and a 400W for flower). Also, I think that optimal lighting conditions are around 75W/sf so if you ran a 400 in your grow space that would be 80W/sf which is more than enough...once again, up to you though.

Lastly, with your cooltube, all i do is put my hand next to the light and slowly move it towards the floor. Once I feel that the heat is not too far above room temp i know it's the perfect height for the plants (very scientific i know).

Hope this helps, man. Keep smoking that sweet sweet pussy.

 

[GetstheShit]

Hmmm...

I knew CMH has a better spectrum than MH or HPS, but I was under the impression that HPS + MH when combined had a better spectrum still. The penetration issue is a good point though. maybe I'll consider a 400 CMH.

 

[FreezerBoy]

Correct me if i'm wrong, but i believe CMH's only come in 250 or 400 W

CMH runs from 39-400 watts. Those smaller than 250 use MH pulse start ballasts. 250 and 400 use HPS magnetic coil ballasts, no digitals allowed.

CMH has more blue than MH and more red than HPS. All in one lamp.

I avoided MH because I didn't want to worry about hooking the wrong lamp to the wrong ballast. With my 250 CMH I can switch to HPS without worry. All of the benefit of MH with: more blue, no switches, no swapping cords, no worries.

 

[Warpainted]

Freezer,

At what stage do you switch to the HPS?

I was thinking about growing with the CMH until about 4th or 5th of flower, then switch to HPS.

Have you compared results from using CMH all the way through to switching to HPS during flower?

 

[FreezerBoy]

Haven't tried it yet myself. I was going to try it on my second Destroyer grow till I smoked some and realized it wasn't what I was looking for. Seemed unproductive to spend 4 months growing a plant I wouldn't smoke for a test. My Mandala 8 Mile beans should be here soon. I'l try it then.

 

[GetstheShit]

CMH has more blue than MH and more red than HPS. All in one lamp

I avoided MH because I didn't want to worry about hooking the wrong lamp to the wrong ballast. With my 250 CMH I can switch to HPS without worry. All of the benefit of MH with: more blue, no switches, no swapping cords, no worries.

If CMH has both more blue than MH AND more red than HPS why bother switching to HPS for flower? wouldn't you do better to keep the CMH throughout? As near as I have read thus far. the blue included won't hurt the flowering process any, neither in yield nor in quality, but if the CMH has all the red and more of the HPS then it should be more than sufficient for flowering. As an added benefit, CMH throws a lot more UVB than HPS helping develop more THC in the trics.

However, this brings me to another inquiry. During flower, would it be beneficial to run the first and last hour of the 12 hour light cycle with a small (a pair of 130W or so) HPS then switch on the CMH (keeping the small HPS on to suppliment) for the 10 middle hours of the "daylight" cycle, more thoroughly replicating the outside light cycle of sun rising and setting?

 

[thecarguy]

Do not get 2 lights if they are under 600 watts each. Waste of money. The best technique with the CMH is to flower the first 4 weeks with it, and then switch to a very red HPS like an Agrosun. This will help your plants finish faster. It will also prevent new, white pistils popping up all over the place in your 8th week of flower, which, for some reason, will happen with the CMH. I would get one 400w bulb if I were you.