Hello. I just started my first grow with White Widow auto-flower. This is an indoor grow and I’m using a tent 4’x4’. I am just approaching the end of the 2nd week.
A lot of guides say that you must have your lights very close to the plant. I have the Vivosun MH 600 watt bulbs and when following the distance recommendations, the surface temperature of the plants/pots get to 95 to 100 degrees Fahrenheit, but the room is only 70F. (I have a thermometer for the room and right by the plant.)
When we talk about appropriate grow temperature are we talking about room temp, surface temp or both?
Ideally I’ve done my best to minimize these high temperatures and keep the lights as close as recommended, but as the plants grow I don’t want to kill them off inadvertently from high heat.
Thank you for the quick reply. I was eyeballing the distance from plant to bulb maybe it’s too close. I’ll double check. Im guessing that those surface temperatures are too hot for the plants?
A good rule of thumb would be if it’s too hot for the back of your hand it’s too hot for the plant put your hand right above the plant if the bulbs getting your hand too hot the plants too hot
When I used a 600 watt MH I kept it about 24"-26" above the plant tops and I used air-cooled hoods to keep tent and plant canopy temps under control (under 80F).
I went led. Started with mh/hps. Got tired of heat. Also took up room and power was expensive. Cool tubes and all the cooling i could muster. Hated it myself. Sold all bulb lights and went led. Ill never go back.
I started out with good quality LED ( fortunately ) and now have a collection of 7 LED lights totaling 1160W. But at one stage I bought a 600W HPS because of the price and soon learnt it ate energy and made heat like no other! But it’s nice knowing I have a back up light for those dark times lol.
