High all

I have noticed that a lot of us grow in the loft (steve the weed, IcaneBud, bcpete, mellow, myself etc) and i was wondering how different people deal with the increased temperature of the summer. This may also help those beginners that are experiencing hot summer temperatures for the first time.

I have built a room within my loft with 400 cu/m per hour of extraction with 240 of that pulling directly from a home made cool shade. There is plenty of air exchange going on. However, lofts tend to get really hot with the sun beating down on the slates all day. When i first grew in the loft i used to leave the hatch open during the day and i put a big box fan over it pulling air into the loft. That is not an option anymore as i am far more security conscious and the loft space is situated differently.

Are there any cheap and effective ways of cooling the space short of buying an air conditioning unit?

Chip

Insulating between the rafters on all elevations exposed to the sun will stop nearly all heat build up. 50mm jabalite is the cheapest and quickest option.

Brilliant

Cheers OT1

Chip

hi, in a pinch i have used four 6 pint plastic milk containers which i fill with water and place in freezer, while the lights are off. once frozen solid place the four containers in a kitty litter tray to keep things dry.
place on the floor behind and under oscillating fan.
the cold air rises and is drawn through the fan, lowering the temperature considerably.
i have brought down the temperature from the mid 90's down to the low 80's using this free method.
i still use the frozen containers, which stay frozen for about five hours when it is very hot.
cheap emergency method if your extractor breaks down, or cannot afford one.
hope this helps, chip

bc pete

Cheers pete

So if i combine the two bits of advice, i should get a nice cool room!!

Chip

hi , if you fit them snug and keep the lids on they will stay frozen longer. i have four in the freezer while i have the frozen ones in the attic. so you could use constantly.
i am going to buy an extractor as soon as i can afford it though.
sometimes i send the mother in law up there and the temperature drops almost immediatly , kidding!

don't forget the tray though as meltage occurs condensation developes on the outside.

bc pete

hello
i'm burning a 250w lamp in a very small loft space off  the main attic room. the lights run through the night when on 12/12 to keep the temps down. I also have a home made air cooled hood sucking air out of the grow space through the light, this air is then piped through flexi-duct into the main attic room this keeps the temps between 25-35 degrees C. acceptable but not ideal it's gonna be a lot easier to cool in winter.
gusto

easy tip

run your light's at night when it's cooler
and off during the day when it's warm outside

work's for me

OP

I've been doing just that OP as I don't yet have an extractor either and things got seriously hot all the same over the weekend.

This simply wont do any longer tho as I've lots of nice new strains that desperately need a couple of weeks 18/6. I'll adopt Pete's method and look into the insulation as OT1 suggests and have the light off from 10:30 til 16:30.

Thanks guys

mines getting hot right now too. i have adopted to take off blackout and open skylight. one fan blowing on ballast
i have to say that the heatshield graciously accepted from hemlok works
i have lowered light and fan directly upwards towards light
also oscillating fan for plants themselves
with the frozen milk containers well cannot carry up at the moment , but three six pint containers fit comfortably in a kitty litter box. remember that during meltage quite a bit of water ends up in kitty litter tray. if really hot check after about six hours
in case of overflowage!
also i found it cooler running on sspeed 2 rather than three giving cold air more time to accumulate before fan pushes it out
sativas seem to love two or three sprays during days like these, especially first thing in morning.
amazing how we can find first aid solutions when loved ones are at risk

At this time of the year, clear sunshine on a dark slate uninsulated roof with a southern elevation generates the equivalent of 250 to 350w of radiant heat per square yard. Even with the northern elevations loosing some heat, loft temperatures can easily exceed 150f. You would need a 25 to 30 kilowatt air con unit to bring this down to the mid seventies, its just not on. Higher temperatures during the dark period against the light period will seriously reduce the yield. In addition once temps are in excess of the mid nineties f during the light period they virtually stop growing without very fast air exchange or pref Co2 addition.

As I said before insulation is the most cost effective method of dealing with this prob.

Hi OT1

"Higher temperatures during the dark period against the light period will seriously reduce the yield"

Is this your experience? Ive read that running 3-5C negative diff just shortens the internode with a better yield. I was planning on trying this next crop - not a good idea?

Peace

David

bearing in mind I grow sats and sat dominant vars. Yes in the past I have grown in several uninsulated lofts, the data is hot dark periods cooler lighting periods reduce the yield by 20 to 30% and the bud structure was airier. The best results were when the dark period dropped 10 to 15f below the peak light period. Even in winter when the dark temps dropped to near freezing the yield was still better than in summer. This is the last thing you would expect as the genetics are predominantly equatorial.

I hate to be pedantic but as a physicist I feel its my job. Anyway I can assure you the cold air does not rise. It would probably be better, at least in terms of cold air moving) if you could have the ice above the air flow if possible.

Xantrix

has anyone experienced condensation in their grow spaces from too cold a temperature during lights out?

System
250w Enviro
Dark Room 80cmx150cm tent
GT205 NFT

RH topped out at 90% for a while and bottomed at 50%

Any ideas?

you got an extraction fan kut?? if not then i'd deffo get one!! and a carbon filter while your at it.

T1

I havent and know I should

thought this might be the remedy

You definitely need extraction and a carbon filter. And if you are getting condensation then you have a temperature problem, so you'd better get a min/max temperature meter, and you will probably need a heater. Insulating the roof will help with the temps, but it's not the whole answer.

I have a hygrometer/thermometer (max and min) and yes there is some wild fluctuation from time to time. Its my first time upstairs so its really a work in progress.

I opened the top vents on the tent and this seemed to help. just checked and no signs of condensation. I am installing a 6 inch clip fan tonight for a bit of curculation but unfortunately the ruck fan I want is gonna have to wait as the xmas cash monster is still biting. Ive been looking at cheaper options for extraction and some kind of temperature control/heater but havent found anything cheap or efective enough. Anyone have any cheap or DIY options they could recomend?

Also I have a 400w (or 600w I cant remember) HPS coming soon that I used to use a few years back but im worried that the heat will become more of an issue as the tent measure 80cmx80cmx150 (had to chop it down as it wouldnt fit in the rafters).

I spose the more I move on and the more enviromental control I get the more stable the grow will be (he said hopefully)

Good advice..
You can buy an oil filled for under £20 from most of the diy chains but I don't think that is your problem.
The problem is the tent itself. The tent cannot give you good growing conditions because you cannot control the environment. It has no insulation against hot or cold. You are getting condensation within the tent at the moment because you have a rapid cool down after 'lights out' because you have no air exchange.
Controlling temps in a loft is tough work, I wish I had a cellar, at least the heat would be more controllable and I would be well toasty in my living room.

A proper answer is to either 'insulate out' the whole loft space or if that is too big then build a room within a room. I believe you have to properly board out a section of the loft i.e. your chosen growing space and hook up your fans.

I don't want to piss on your bonfire but I think the tent is designed for other situations.

Regards
chrisesq

Condensation has gone now the vents have been opened so my main issue is temp control after lights out. I have a small 500w electric/oil filled radiator which I will set up tomorrow for lights out. I know that extraction is my main problem at the moment but i get paid Friday (thank god) so I will sort something at least, this weekend. The plants are only 3 inches at the mo and still doing well so i should be fine for about 7 days. but the game is on

Ive had very successful grows with budget/DIY systems about 10 years ago in wardrobes but the loft in winter is a whole new ball game Still as I said in a previous post, this is the only space ive got now due to security etc and its a first attempt so really its a work in progress (and a fun lerning curve to boot)

Im gonna keep posting in this thread as all your advise is helpfull and handy - share the knowledge

Heya mate , what ever you decide to do up there you are going to have to insulate it , ie large room in room or small insulated scog box ? Seeing as you have just the three on the go it could be a good option , but any thing up there you will need to insulate it to have any chance at holding environment .

My experiences of loft growing are, insulate all of the rafters and your growbox. Draw in air from the floor below (which will be at a lower ambient temperature). And flower at night. By flowering at night, temperatures of 20 degree's lights off, 25 degree's lights on were achieved.

And realistically, look at buying the biggest fan you can afford. You can always turn a fan down, but you can't make it go faster.

Right, just a quick update if anyones interested...

500w oil heater added for lights out
6inch clip fan infront of air intake added

so far so good, temps have stabilised to 19c lights out 26c lights on, plants seems happy and no condensation

this will have to do for a week or two till i stump uo the fan for the ruck I wantu

If they are only 3 inches at the moment you have plenty of time left on the clock before they start smelling. NB Greens have the Rucks on special offer at the moment, ten quid off. Best of luck with it.

Thanks all, Will check out that ruck fan at greens also (i missed that last time i was on the website)

As stated before, temps are fairly stable now and plant are looking healthy

I think this grow is gonna be more of a reactive grow than a pro active grow

Ive also been thinkin about the scrog box idea and keeping the tent as a mother room


HHmmm, should really start a grow thread I spose