Problems With Veg Under 600w

[Tylergrower]

hi guys. i'm trying to grow under 600w bulbs at temp not exceeding 28c and in coco coir at ph 5.8 ec 1.4 using a 3:2 ratio of pink:brown of the gh series of nutes. temp at canopy seems fine. distance of light has been 4 foot but reduced to 3 feet now. temps seem fine but i've not had good veg growth since switching to the big lights. under 100w tube i have beautiful growth but under big lights i'm having stunted growth and deficiencies. as soon as i put them under 100w bulb i have nice new growth. i don't know if its a watering problem or a light problems or something else. Strain is critical kush. I get the feeling it may be a watering problem disguised as a light problem, how wet should I keep my coco coir and how often should I water. Could it be something else. I'm using AC also if that helps. Thanks for any help and sorry about my bad editing.

 

[stonestacker]

Humidity can play a huge roll in veg growth. Try looking into vapor pressure deficit.

 

[Dunge]

What are your 600 W lights?
Pics might help. (see 'upload a file' button)
Might put that 100 W concentrated on a branch and see if it improves that branch.

 

[Tylergrower]

Humidity can play a huge roll in veg growth. Try looking into vapor pressure deficit.

Thank you so much for your reply I would never have considered this. I checked my humidity today and it was at 10%. The Air con sucks a lot of moisture out of the air as its cooling those 600w lamps. When I no longer needed the AC Im getting beautiful growth under the low wattage bulb. I guess I need to increase the humidity to counteract my AC dehumidifying my grow room. I guess ill have to get a humidifier or something.