315w cmh

[DirtySteve]

New to indoor growing and I have a 315w cmh with a 3100k bulb in a tent I’m wondering what people are experiencing to be the best height for seedlings to veg to flower. Please advise.

 

[MIMedGrower]

I was at 42” for seedlings and 18” peak bloom adjusting along the way for best results in a 3x3 tent.

 

[DirtySteve]

Thanks. I have it at 40”, 18- 22” seems to be the average I have read. How soon do you find it safe to move this towards seedlings ? What is your timeframe for moving it lower, what determines when it’s time ? Plant size , age ?

 

[4plant]

I’ve left the light “up”start to finish ( 8’ ceiling) on a table so seedlings started at 48” or so aboveand I never changed the distance. Check the canopy temps though, the lights intensity is great, but the lack of heat output is what I try to manage now. In cooler weather I’ll bring the light down to warm the canopy up and zap the high humidity,in a Canadian basement anyways.

 

[DirtySteve]

Thanks for the advice and sharing your experience everyone. I’m better off now than I was a few days ago

 

[DirtySteve]

Impressive growth even at 40” with 1 of these bulbs in a few days.

 

[DirtySteve]

Does anyone know of any strains that do well with a lower humidity level ?

 

[4plant]

How low is your rh? There are probly strains that do well with your situation but getting humidity levels in a better range is well worth the time.

 

[10w30]

critical mass maybe? pure speculation

 

[DirtySteve]

Between 30 - 45. Average seems to be 35 seems to be the average shortly after feeding

 

[DirtySteve]

Update for people to see. Thx for help so far. 2 females. 6 weeks to go in flower stage. I do want to know what levels others like to keep the humidity around consistently, what is ideal ?

 

[DirtySteve]

 

[DirtySteve]

Oops. Sorry for duplicated pics.

 

[DirtySteve]

A little plucking of a few giant fan leafs in the way and to level out the canopy. Much better results in a week.

 

[DirtySteve]

 

[DirtySteve]

4x4 space and lm kinda glad I I only have two in there for my first go at it.

 

[juggernaut]

you need more light or a smaller growing area. Get rid of all your fan leaves. With hid's You should be running 85 watts a square ft minimum. I would say over 100watts a square foot. Cheers

 

[MIMedGrower]

you need more light or a smaller growing area. Get rid of all your fan leaves. With hid's You should be running 85 watts a square ft minimum. I would say over 100watts a square foot. Cheers

Sounds like a lot of watts. I have only read that 50-60 watts of hid lighting is needed and at 60 co2 is preferred.

I use 48 watts per square foot in the flower room.

 

[MIMedGrower]

And i should add that a 315 cmh puts down more light per watt than a 400 hps and does fine at 35-40 watts per square foot. It is designed to flower a 3x3 area. I like 2.5 x 2.5 in an open area. More for a reflective tent.

 

[Dbear180]

Sounds like a lot of watts. I have only read that 50-60 watts of hid lighting is needed and at 60 co2 is preferred.

I use 48 watts per square foot in the flower room.

I only run about 30! 3x that would be eye ball melting bright.