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Growing Help [Low Temp Vs More light + High Temp]


New Member
I am currently starting my 1st grow and started setting up my grow area while the seeds are germinating.
I actually just signed up on this site to ask an important question:

Grow Area : 3ft x 3ft x 7ft height.
Intake : intake into the grow area providing air conditioned air at 21C installed at the bottom of the room
Exhaust: bathroom extractor fan at the top extracting 200 CFM

I was able to fit 2 x 400W MH/HPS fixtures but they are not cooled.

Light Distance from the pots is 27 inches (70 cm)

Now i put 2 pots in the grow area and using my Thermometer at the pot level i am getting 91- 93 F with the 2 lights on.

I decided to switch one of them Off so now i have 1 400W instead of 2 x 400W.

The temperature dropped to 82F when i did that and i was also able to bring in the light down to 23 inches (55 cm)

Now my big questions is, which setup will provide me with better results in terms of quality and yield.

Setup 1 : 2 x 400 W at 91-93F with lights 27 inches away from plant
Setup 2: 1 x 400 W at 81-83F with light 23 inches away from plant

Thank you all


Plant of the Year: 2014 - Plant of the Month: Dec 2014 - Nug of the Month: Feb 2015, Mar & Aug 2016, Dec 2017, Aug 2018, Jan 2019 - Nug of the Year: 2017 - Photo of the Month: June 2018
You're better off with one 400 and lower temps. :3:

In your 3x3, 400 watts gives you almost 50w/square foot already, so there's not a lot to be gained from another 400 watts. And plants have a difficult time metabolizing when temps get much over 85F, unless you boost CO2.

And you can also drop that light closer to the plants. I have an open 600W and I can run it as close as 14 inches.

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