Heat problem

P

pypcio

New Member
Hi there,

I grow 10 plants - 5 autos and 5 other ones. I got two CFLs running at the moment (1x 250W and 1 x 300W - both dual spectrum) inside my hydroponic tent (1m x 1m x 1.8 m). Temps inside the tent are to high sometimes even up to 90(i hope to drop it down at least to 77 in next couple days).
I know CFLs are fine for vegetative stage but are not great for flowering stage. I would like to upgrade my lights to 400w HPS.
Question 1: Will this light give much more heat comparing to my CFLs?
Question 2: If 400w HPS light is going to be overkill, will Mars II LED Grow Light 700W run cooler and give beter yield than my CFLs?
Question 3: What about 250W HPS?

Thanks for help:)
 
Question 1: that light will give you at least 100%more heat. HPS runs very warm.
Question 2: LED will yield better than CFL. It should run a little cooler.
Question 3: what about a 250watt HPS? It would work in your tent but yield might suffer a little.

Honestly it sounds like you need to get some sort of exhaust fan set up to help control your temps. Just to correct you CFL can be just fine for vegetative and flowering stages. You want 6500K lights for veg and 2700K lights for flowering. Check the temperature rating of the CFLs that you buy. You would need 2 sets though if you are growing all in one tent.

Good luck on your grow. Set up a journal I know the community would love to see it. Also lots of help will come when and if you have any issues.
 
DarlingNikki said:
Question 1: that light will give you at least 100%more heat. HPS runs very warm.
Question 2: LED will yield better than CFL. It should run a little cooler.
Question 3: what about a 250watt HPS? It would work in your tent but yield might suffer a little.

Honestly it sounds like you need to get some sort of exhaust fan set up to help control your temps. Just to correct you CFL can be just fine for vegetative and flowering stages. You want 6500K lights for veg and 2700K lights for flowering. Check the temperature rating of the CFLs that you buy. You would need 2 sets though if you are growing all in one tent.

Good luck on your grow. Set up a journal I know the community would love to see it. Also lots of help will come when and if you have any issues.
Click to expand...

Sounds like you need a fan to extract heat/hot air. I used 8 (42w) CFL's and the temp between the lights was 140 degrees.

You can VEG and flower with an HPS light. But you will still need an exhaust fan. 90 degrees is doable... But, 92?, 95+ wont work to well.

Many LED's still produce heat. That is why they have or come with small fans installed in them. Yes it may be less heat depending on what power/wattage you get.

In the long run... If you want to grow it will be very beneficial to have an exhaust fan for heat removal and circulation/air flow exchange.
 
Hi guys,

Thanks for your quick respond. My CFL lights are dual spectrum so both give 6500K and 2700K lights. I get from them 48k lumens total. I am planing to use LST method to keep my plants more flat so all of them are going to be around this same height.
It is going to be one time grow so not sure if is any point invest $300 in LEDs:/ or is it? Led will be answer for all problems - heat and not enough light.

Also my tenet is inside back garden shed. I have neighbours around so i can not cut many ventilation holes as they will see all of this light coming out. I have few ideas how to provide most of the heat from the tent to outside using some a carbon filter, few computer case fans and flexible ductings.

Would you recommend any quiet powerful exhaust fan instead small case fans?:>

Scarfinger68 i noticed in your journal you transplanted your plant on the edges of new pots. It seems to be great idea as is easier to keep them all under one light. Will it not affect theirs roots at all?
 
For a one time grow I am not sure I would spend that kind of money....but to each his own!

It should help a little if you put bends in your ducting to conceal the light. Filter will block more. Use some panda film for around the holes. If you still seeing significant light I would would build some sort of flapper to knock out the light even more. If you had the room I would go powerful exhaust fan, but you tent wasn't huge. I might go with one really quite bathroom fan from Home Depot. It should move enough air to cool everything.
 
pypcio said:
Scarfinger68 i noticed in your journal you transplanted your plant on the edges of new pots. It seems to be great idea as is easier to keep them all under one light. Will it not affect theirs roots at all?
Click to expand...

I did this try give more room the the LST training. Roots seemed fine. Good sturdy plants.
 
After thinking about all cons and pros i decided to go for Mars II LED Grow Light 700W. Not sure if i should go for 900w one as it seems to be wee bit more expensive. How do you think, is 900w one going to be to hot for my tent? any difference in yield? Thanks
 
Why not make one yourself? I make my own and as far Mars you will still need to exhaust the tent. The light doesn't produce the heat the vents do because the fans are blowing on the heat sinks and blowing the heat away from the diodes and releasing it into the tent.
 
Hi Bruce,

Thanks, but what do i have to do to make one myself? and what would be roughly cost to make one equivalent to Mars 700W? To be honest i do not have much time as temps in my tent are going up to 92 now:( Probably i would have to read a lot, then shop around and then make one. Or is there any easy fast way to make it?
Also, LED should give much less heat than two CFLs so it would be easier to ventilate my tent without destroying my back garden shed.
 
Hello, pypcio, LED does produce less heat than HPS. MarsII 700w will cover 1mx1m at the height of 0.6m. MarsII 900w will cover bigger coverage, 1.2mx1.2m at the height of 0.6m. Both of them can cover your grow space, while MarsII 900w will perform better during flowering stage. :circle-of-love:
pypcio said:
Hi Bruce,

Thanks, but what do i have to do to make one myself? and what would be roughly cost to make one equivalent to Mars 700W? To be honest i do not have much time as temps in my tent are going up to 92 now:( Probably i would have to read a lot, then shop around and then make one. Or is there any easy fast way to make it?
Also, LED should give much less heat than two CFLs so it would be easier to ventilate my tent without destroying my back garden shed.
Click to expand...
 
SmokeSara said:
LED does produce less heat than HPS.
Click to expand...

Just curious Sara, but do you have any proof documenting that LED produces less heat than HPS?
 
A 700 Watt Mars 2 panel will run at about 300-380 watt. (On a youtube video I see 330 watts being mentioned)
You can assume that all energy that goes in your growbox will turn into thermal energy at some point.
So a LED panel that uses 400 watt of energy will make your growbox just as hot as a 400 watt HPS.

The Mars 2 700 will run cooler (a lot) than 550 watts of CFL, but so will a 400 watt HPS.

For 1x1 meter a 600 hps would probably be better but then you'd have heat issues again. (since 550watt of CFL already brings the heat up too high)
But you can either get a cooltube for the HPS or increase ventilation of your tent.
cooltube3.jpg


Going from 550 watts of CFL to a Mars 2 700 or a 400 watt HPS will not give better results (probably), but there will be less heat.
A HPS is a cheaper investment than a LED panel.

In the end for a 1x1m tent, you will surely need an exhaust vent to battle heat.
 
"Heat" is such a relative subject. A box/tent is just a small concern. I run about 600W of LED in a 4x4 tent. It sits in a 10x10 room. You'd think hot outside = trouble. My situation is exactly the opposite. When it's cooler out, the house AC doesn't run and the enclosed room (door locked) will warm up as the AC doesn't flow through the vent. I added a 5k btu portable AC and set the thermostat to 75. It doesn't run much but without it the room will slowly start to warm up on a cool day.

I gave my opinion on your questions but deleted it because it pretty much plagerized everything HydroDyna said. I'd play with your ventilatin. A few light traps, duct mufflers, ... I,d even think about some drain tile and a below ground exhaust to a safer spot in the yard. I will add this... If you're worried about the neighbors for "legal reasons", you are taking a risk with your thermal signature and/or RF interference with HPS. Look into this if you go that route. Might be a reason to go LED or stay CFL.
 
Hi all,

Thanks for your responds. I decided to go for 700w mars lights after all. I received it yesterday. I was checking temps all evening and this morning as well. Temps in my tent are around 75-77 which suits me great. I know it was expensive purchase and i love to go for HPS lamps but as Spitz said for "legal reasons" my back garden shed can not get too hot.
Now i do have to think about smell problem in next couple weeks time;) i hope that my carbon filter will do the job.
 

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