to move lights, or to remove lights, that is the question

[DannyGreenEyes]

I'm about to start my first grow and I'm having temp problems. I've gone through just about every other alternative so I guess I'm either going to have to raise the lights or remove one. I have three 400w bulbs, 2HPSs & 1MH. Also two 10.0 UVB bulbs.

I have the lights hung 32" above the temp tester. And the question is this, would I get better results if I remove a light or if I raise the lights?

I'm starting with 8 plants (8 sq ft) and I'm going to have to force flowering after about a month of veg on this first grow (money wont stretch 4 months) and I want to get them as big as possible before the month is up.

This is an indoor grow and venting is not possible.

Thanks for any help you can give.

 

[Seasonal Smoker]

You probably want to use just one or two 400 watters. If you do raise them to high you will lose lumens. I wouldn't raise them any higher than 2.5ft. Even a 150 watt lamp without venting can be problematic. I wouldn't use HIDs unless you can properly vent them. I like CFL lights. A 250 watt CFL will give you 15,000 lumens and you will be able to keep it a lot closer to your plants.

 

[chknhwk]

where do you have you plants a couple of floor fans to move the hot air around and having a seeled hood helps alot even in my case with only a 250

 

[DannyGreenEyes]

where do you have you plants a couple of floor fans to move the hot air around and having a seeled hood helps alot even in my case with only a 250

I had gotten some bad info when I bought my lights, these have cheap hoods that are wide open. But I solved my problem for the most part.

I have the plants on the floor, a portable A/C with the exhaust run through a DIY odor controller and run out a sliding glass door. I keep the sliding glass door open to keep the bedroom cold, this is where the A/C pulls air from. I moved into the living room. And I have 2 fans going, one oscilating on the plants, and one in front of the a/c pointed strait up. (I tried pointing it at the lights, but it didn't do much good)

I have 2 of the lights & both of the UVB lights running and keeping it right at 80 degrees.

I might have to put them into flower soon, still trying to figure out finances, we'll see what happens.

This harvest I'll try to buy some better hoods along with flexible ducts & inline fans.

 

[RickWhite]

8 square feet is a 4' X 2' space in which case 2 400W HIDs is more than sufficient. Do you mean 8X8 which is 64 square feet?

At any rate, I would remove the UV lights first as there is no real evidence they are beneficial.

Next, I would look at raising lights. Removing lights will decrease the total heat of the grow room but only raising them will decrease the radiant heat radiated from the bulb to the plant. If you had a single 400W in a 12X12 and had it 6" from the plant top it would still burn. Plus, remember, more lights = even illumination.

 

[Dirtfree]

Why cant you vent?

 

[DannyGreenEyes]

Why cant you vent?

Because the walk in closet is "land locked" so to speak. I was planning to hook up an exhaust to the near bye bathroom exhaust fan, but the exhaust fan ended up being a blind fan (no exhaust, just a fan in a hole in the wall)

I ended up finding a way to keep the sliding glass door in the connecting bedroom open so I can now vent and my portable A/C can pull cold air. I just have to sleep in the living room.

But since this cold front started I've been able to run 2 of my 3 lights. Yay! lol I'll upgrade and buy some good sealed hoods when I get this harvest in, and run some ducts to the sliding glass doors. That will help the plants even though I'll still be on the couch. lol

 

[blowseed]

Is the thermostat in direct light if it is it will give a false reading, move it up so it is just out the light see if the temp drops. good luck

 

[DannyGreenEyes]

8 square feet is a 4' X 2' space in which case 2 400W HIDs is more than sufficient. Do you mean 8X8 which is 64 square feet?

At any rate, I would remove the UV lights first as there is no real evidence they are beneficial.

Next, I would look at raising lights. Removing lights will decrease the total heat of the grow room but only raising them will decrease the radiant heat radiated from the bulb to the plant. If you had a single 400W in a 12X12 and had it 6" from the plant top it would still burn. Plus, remember, more lights = even illumination.

Actually it's a little smaller than a 3' x 3'. I have 7 plants in 5 gallon pots & 1' saucers. I guess the pots are about 10" in diameter. I have them in 3 rows, the middle row has 3 plants and the other 2 rows have 2 plants, and I kind of got them set up like bowling pins if that makes any sense. I have the pots as cloes to one another as possible with no spacing between them.

The heat and UVB are the only things I'm having any problems with. The heat I now have under control and only the youngest leaves are having problems with the UVB. I just raised the UVB lights about 3". They're farther away than the HIDs.

The UVB lights I'm using for 2 reason. To help keep the mites, aphids, and thrips away (just had to get rid of thrips 2 nights ago) and also to increase potency. I've read a few published scientific studies on the effects that UVB has on MJ and it's true dude, check out this pics. Seeing is beleiving.

 

[DannyGreenEyes]

Is the thermostat in direct light if it is it will give a false reading, move it up so it is just out the light see if the temp drops. good luck

The thermometer is sitting on the rim of the pot in the center. It should give an accurate reading as far as what the plant is feeling at that level because the plant is also in the light.

The top of the plant is probably a bit hotter, so in that way it's probably not 100% accurate. I plan on hanging the thermometer so I can raise it up & down so I can test at the level of the plant tops, but haven't had the time. I still have to get in there to pull clones and check to make sure the Thrips haven't returned. Hopefully I'll get to do both tonight.