Making LED work in a cool basement?

olegren

Well-Known Member
New grower here looking for insights as I put together my room. Growing in a small closet in a basement that stays pretty cool year round. 2x4x6 tent and want to go LED because of the energy
benefits.

I have another thread here where I got some great input.


Prompted me to look hard at CMH and may still go that route, but I want to put some numbers in front of you fine people and understand my options. I picked up a proper thermo and gauged temps in the future home last night. Temps outside were about as cold as we get in the winter, and the low in that closet was 60.4. That said, given my space and LED aspirations (Looking at HLG 260 V1) do you think I’d get the thing warm enough?

I don’t want to use anything like a space heater to warm it up in there because of the potential fire risks, and I’ve seen a lot of mixed results in terms of heat actually generated from these LED boards. Saw some feedback suggesting about 8 degrees over ambient in a room that was warmer than mine to begin with. Any ideas? In the summer that room is probably going to be 65-70 easy, so I’m much less worried then.

Put another way: I’ll want to grow with LED in warmer months. Think I can get by with it during the cold too - based on a 60.4 F ambient temp on a cold winter night?

Thanks!
 

sandman83

Well-Known Member
if you go soil route you could raise them off the ground and use heatmats to raise the soil temperature and probably get decent results. You still need to raise the leaf temp I believe for proper transpiration with LEDs. Setting them on the cold ground and trying to heat it would be counterproductive I think.

Or just use a HID and heat with the light.
 

olegren

Well-Known Member
Ya. Led puts off the same amount of heat watt for watt. Your temps going to depend more on the size of your room.
I didn't realize this, but it seems obvious now that I think about it.

I might go down to a 2x4x4 tent. Growing for personal use only. I realize that would cut back on my growth potential, but it would also give a smaller volume.

Thanks for the other thoughts as well. I may have to run two light setups. Trying to avoid investing in an HPS that I will turn around and need to swap out in 2 months, but it never really gets all that warm down here. Just don't want to cool so much if I don't absolutely have to.
 

sandman83

Well-Known Member
I think your only issue after nailing the temp will be getting the RH% back up a bit, probably need some sort of humidifier for the tent. sounds doable to me..


I would not get a 4' tall tent if you plan on flowering in it, just IMHO. Unless you are going to dim the leds way down so you can keep them right on top of the canopy you will still need some clearance for top to lights, and training. subtract another 10-12" for the pot height and drainage that leaves you with very little vertical space for your girls.
 

sandman83

Well-Known Member
I have the HLG 260 V1 coming. I was going to go ahead and throw it in there and see what the temps get to just running. Guess the best way to find out is to try it!
yeah definitely toss the light you already own in first and test it out. I have a feeling it wouldn't be too hard to get the temps up to where you need em.
 

Moflow

Well-Known Member
Im an exception to the rules
I grow in those temps, been doing so for years, usually cooler than that in winter lol.
In soil. I use heatmats under the pots and insulation, especially on the floor. Something like pic below.
I extract air with a 3" pc fan dimmed down and have a 4" carbon filter n fan that recirculates scrubbed air within the tent.
I use tepid water on them, Not freezing cold!
It shouldn't be too hard to insulate a 2 x 4 x 6.
71BSL+n9unL._AC_SX679_.jpg
Lights on temps ~ 22°C 71F
Lights off temps ~ 8°C 46F
There's an optimum temp for cannabis but it'll grow in a wide range of conditions.
I hope this helps.
 

kroc

Well-Known Member
Ya. Led puts off the same amount of heat watt for watt. Your temps going to depend more on the size of your room.
yeah but he is using like 240 w of led if im not mistaken.. and he could be using a 600w hps. so watt for watt wouldnt that equal more heat or am i just too high for this??

edit: saw youre in a 2x4 so 600w hps is a bit of an exaggeration but still
 

Humple

Well-Known Member
I grew in a cold basement for a couple of years, and it was a constant battle to keep the environment controlled and the plants healthy. Ultimately gave up and moved the grow upstairs, to my bedroom. If you can insulate the space, or even just the tent itself, you may be okay. Or you could try to get yourself some of that magic tomato food that @Moflow uses? (Magic is the only explanation for his plants' inexplicable resilience and resistance to the cold!)
 

olegren

Well-Known Member
Thanks, everyone, for the fantastic input. Been indisposed but finally getting a chance to reply. Ended up modifying my HLG order to a V2 and very much looking forward to putting that bad boy to work.

Moflow, thank you for sharing so much detail on your process. Can you tell me a bit about the way you're insulating the tent? It would be fairly easy for me to insulate the closet altogether; but of course the tent would require less effort since it's smaller. Also a great idea regarding the mat. I was reading about those but kind of wrote it off due to a lack of understanding. Didn't figure this would contribute so much towards ambient temps. Haven't even got so far as to consider medium and things like soil temp, but I will clearly need to deal with that as well. The floor down there is ceramic tile and quite cold even on a hot day.

I'm definitely going to creep on your grows and learn what I can.

Humple - Thanks for sharing your experience on this also. What sort of lighting were you trying for in your basement? Was the temp situation similar to the one Moflow described? At the end of the day, I guess I don't know what I don't know. Beyond ambient temps, I just don't have a lot of data yet -- but I'm looking forward to hooking up the LED and seeing what those can bring the tent up to by themselves.

sandman83 - Appreciate the clarification on height. I haven't done a lot of reading about ideal light distance yet either, but I can see your point. By the math, there's not a lot of room left. Was thinking less height = less space to heat, but I can comfortably fit a 6' tall tent in there. Might as well use it.

kroc,Skoal - Point taken. I'm still inclined to look into an alternate light that produces more heat rather than introduce a heater, but I guess I should at least see how far off I am before I make that call. If a few degrees, maybe it wouldn't be that big a deal to run one with a good thermostat. In parallel, I'm using this as an excuse to investigate some HVAC issues. There are vents in this part of the house - they just don't seem to do a lot. There's a damper in the system that I think may be broken.

Psuargo, Humple - Is the point with autos that they don't actually require any dark periods? I originally intended to start with them just because the process seemed more fool-proof and the yields were more manageable (I don't want to end up with a lot more than I can use personally). The more I read, the more some of these posts make me want to re-evaluate though. But if there's a benefit in being able to light them 24/7 and skirt around this problem during cold weather, that seems like a huge plus.
 
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