Northern Lights 315w CMH

Just started my first grow under a CMH. I've had two successful grows under a little 150w HPS and decided it was time to go bigger.

I'm growing one feminized Northern Lights plant from seed in 100% coco (dtw). My goal is to pull at least 10oz's from this grow, we'll see...feel free to ask questions or offer advice.

4x3 Tent


Max tent temperature 77F with romote ballast outside of tent.


3 days above ground.

I'm in brother good luck. I am currently flowering my first grow which is NL as well in my 3x3 under a CMH too and she's loving the light but hasn't been under it her entire flower period so I am curious to see what your's will do from beginning to end under it. What Kelvin rating on your Bulb?

I'm running the 3100k philips bulb (start to finish).

citeh said:

I'm running the 3100k philips bulb (start to finish).

Click to expand...

Nice that's the same bulb in my light in the flower tent. Will be nice to see how it does in veg.

I couldn't find much info on how close to put the light to seedlings, I've got it about 36" above the seedling with no stretching or visible light stress.

citeh said:

I couldn't find much info on how close to put the light to seedlings, I've got it about 36" above the seedling with no stretching or visible light stress.

Click to expand...

I have mine in a flower tent so can't help there. I would say if you want to see where you can push it to just try very small increments and check after an hour or so

Day 4 above ground, slow and steady.

Day 5 above ground. Second set of true leaves have appeared. Stem still has a slight curve to it, thought it would straighten out by now.

Nothing much to report. Day 6, still alive, still healthy.

Day 7, about ready for a light feeding.

the phantom is a good looking and well made unit. I wish it had the reflector from the suntec though.

the ballast gets hot, I had to get a little desk fan on it.

but external ballast is a better design IMHO, you can change it out or use a after market one.

I cant think why when LEC/CMH they wanted the ballast in the unit. I cant think of a single reason. other then cost.

Agreed, I wanted a remote ballast and it just happens to be about $100.00 less than the sun systems. My tent peaked at 81F when it was 92F outside. I'm also not running an exhaust fan, so I've been pleased with the heat output.

Day 8. Third set of true leaves starting to show. She also got her first feeding of 2tspn of floranova bloom and calimagic /5g at pH 5.75.

citeh said:

Agreed, I wanted a remote ballast and it just happens to be about $100.00 less than the sun systems. My tent peaked at 81F when it was 92F outside. I'm also not running an exhaust fan, so I've been pleased with the heat output.

Click to expand...

they do make a cooling (adp) though I never seen one hooked up
http://hydrobuilder.com/phantom-cooling-kit-for-phr3150-cmh-reflector.html?dzid=csegps_PHR3150CKT&gclid=CjwKEAjwqdi7BRCL6Zmjk5-rsTwSJABmrVabWG19iJLErf7mPaGshWexcv4vA00qzr3RtrcvlN5mSBoCJLrw_wcB

Day 10, looking healthy.

Day 13, working on nodes 4&5. No stretch with this 3100k bulb.

Day 14, had a minor pH problem (probe was measuring 1.01 too low!). Recalibrated and flushed with 2.5tsp of floranova bloom and calimagic /5g. Perked right up after a few hours. Also the roots are showing through the bottom holes already in a 3.2g pot!

Day 21, topped her a second time today. Looks angry, but I'm sure she will rebound by tomorrow.

It's been difficult topping and training with the CMH lamp because the node spacing is so tight.

a little canna BSDM: when you run a few times, start keep track of days it takes to recover, IME: there is a sweet spot, on time you can spend training before you are just running in to time you could be on another cycle.

or get a test tent: mine is where old moms go, or I test unknown clones and try all sorts of silly things.

Day 30, topped 3 times.