Seedlings under 600W HPS Growlux

[PrimoOnlyForMe]

Hello all! I'm new to posting, but have been reading for months now.

My question: is there any problems other than heat for seedlings to start out under the HPS instead of CFL's? How high above the seedlings can I go before they start to stretch? I'm trying to keep the temp down. At two feet above the seedlings, the temp is reading 85. I'm thinking I could go three feet without any stretch?

Setup: 3x3x7 cab, 600W HPS Hortilux (vented) Vortex 172cfm blower. One Vortex 172cfm blower sucking in fresh air in the room from a portable air conditioner set at 72 degrees. Growing organically w/FF soil.

 

[siegalsmoker]

Well your area is about the same size as mine, and my grow started off with my 600w HPS.. Heat was a slight issue at first but found some ways to work around it.. I started my last ones with CFL's and they are stretching a little now.. If you did start with your HPS (mine was 6' high) and I had it maybe... a foot or even a lil less from the top.. When they started to fil out attached it to the ceiling did a lil LST and .. JMO.. Good luck.. keep us posted..

 

[snuggles]

Tough call, heat is an issue and if they stretch which I think they will at 3 feet JMO. Maytbe some more fans? I have my 600 about 6 to 10 inches from the seedlings but I'm using a cool tube. Best bet is to keep an eye on them, if they stretch you have to get the light closer. Man with that kind of ventilation running you should be fine IMO. Maybe the fans need some upgrading but I can't see why you would be having heat issues with the AC running.

 

[parkingjoe]

i reckon itll kill the seedlings too much intense heat along with intensity of light.

pkj

 

[Dankerz]

where is your ballast set up? is it in the growroom.? that could be your heat buildup! 2-3 feet above them with 66watts per sq/ft the 600 in a 3x3 should still do fine but if it was me id be at around a foot even if poss!. im setting up a 4x4 under a 600w now you got me worried about temps.. let us know if you get it under control cause you should be at around 78 not 85..85 will make them stretch or get burnt etc gotta get the temps down dude!

 

[Timmyjg6]

Yeah i would also sagest moving up to a 6" 450cfm vortex sucking the heat off the bulb... 172 sounds low, is 172 the max? are they actual vortex's i did not know they made them that small....

 

[smokybear]

First of all, welcome to MP. It's good to have you here. I hope that you find everything that you are looking for..

85 isn't that bad, I think. If you can get the temps down a bit more, it would be better but they will be fine in there. I would start with the light a good distance away. PKJ made a good point. The intensity of the light may slow the seedlings down a bit in the beginning so start the light off at like 2 feet and lower it slowly over the next week or two. If you start to see stretch, lower the light a bit more. Hope this helps. Do you have any pics of your grow? We would love to see. Keep us posted. Take care and be safe.

 

[PrimoOnlyForMe]

I found that using one of the weather station temp monitors is not a very accurate way to measure the temp. I used an infra red temp sensor and found the tops of the plants at two feet from the light (with cool tube) 80 degrees.Something else interesting, with the portable air conditioner, they supply you with a 5 inch diameter PVC tube to vent out the hot air. Well, six feet of thick PVC tubing is putting out 120 degrees radient heat from the tube itself. I'm going to try to insulate the PVC exhaust and see if that helps the temp in the room.The exhaust from the cool tube is only 75 degrees as is the exhaust for the cab itself, although that exhaust isn't doing much since the cab is wide open to the cool air in the room.For now the veg is wide open for the air, and the flower cab is not running. I could always keep the veg cab open, but will need to make sure I can get enough cool air inside the flower cab.

 

[docfishwrinkle]

i'd just veg under cool white floros (6500*K)kept 2"-4" above. nodes were stacked top of eachother. had no prob w/ heat & low cost plus not really needing red end of spectrum so save the life of & $ of hps. i run in basement temp of 66* w/ floros 2-4 above kept temp@ 78-80. oh i also lined reflector of floro w/ mylar. 4' shoplight wally world $9 2pk 6500K 48" bulbs $8 no need 4 ac or hps heat no issue

 

[PrimoOnlyForMe]

48" lights will not fit in a 39"x39" grow cab! I've rigged up some CFL's to use for sprouts and clones, but for the first batch, they are getting 1400 lumens of light.