It sounds to me like you have more ventilation problems than anything else. I couldn't quite figure out how many watts of light you have under those six plants, but if it is anymore than 1000W, it is overkill unless they are huge plants. The younger the plant the more sensitive they are in regards to standing the heat as well as the light. If you place say a 4" tall plant under 1000W light 18" away it will have a lot more problems than one that is 30" tall. For an ordinary garden, say they are flowered when about 10" tall, 600w would be fine..
Now for your ventilation.....
Assuming you are running your lights at night (which you probably should be) simply because the outside temps are cooler at that time. Say at midnight it is 40F outside and it is 90F in your growroom, which is how I read your note, that is a difference of 50F, or 50 degrees warmer than the outside air temperature. Having worked in the heating, ventilation and air conditioning for 10 yrs, there can only be two reason for such a high difference.... that is, a 50 degree difference. The reasons are quite simple. You are not getting the 40 degree air INTO your room, or you are not extracting the warm air OUT of the room. When you are bringing the air into the room, this air needs to come from the OUTSIDE of the house, not from warmer air that is in other rooms. FRESH COLD in. Now, if you are bringing in 700 CFM of cold air, and then Extracting the HOT AIR out at the same rate (700 CFM in this example) your temps in your room should be no more than 10 degrees warmer than the outside temperature. That doesn't mean your room should be at 50F, but it could be. You will be able to use your fans to control the temps. Put the fans on a timer and run every 15 minutes per hour, or whatever schedule works with the current outside temperature.

If you have temps in the high 80's now when the weather is still cool, what will your temperatures be in there when the low for the night will be 70F outside? You definitely need better ventilation than you have now!

SpaceNeedle
SpaceNeedle Reviewed by SpaceNeedle on . i need help with fertilizer BAAAAD HI GUYS im new and i just harvested my first 6 plants ever, well the plants didnt smell at all and the buds were very small they did the trick so far but ive got every tom dick and harry saying do this , use that and the 3 shops in my area are all telling me to use diferant fertilizers, i need some good advise on what to use for all stages of growth please guys , my wife and i are disabled and have our doctors note and all i just am haveing a hell of a time figureing out whats wrong my new Rating: 5