temperature question

[ukgreen]

hi all, first post.

strain - dutch passion (fem), oasis (northen lights #2)
space - wadrobe, just under 4 sq foot, height 6 ft
lighting:
40w cfl (seedling's),
250W blue envirolight (veg),
250/400w red envirolight (flour)
venting - passive (semi open door) / 6" desk fan.

right this is my first grow, but i am having major problems with the temperature. i cannot seem to get the temp down that much.
light on, door closed, no fan - 107 deg F
light on, small opening, no fan - 103 deg F
light on, door closed, fan on - 95 deg F
light on, door open, no fan - 95 deg F
light on, door open, fan on - 85 deg F

i dont know if the thermometer is faulty as it's a very old POS, but i can only get the temp down to 85 deg F. and this is with a 'noisy' fan on and the door wide open (not ideal).
i don't really want to spend any more on equiptment, and cutting holes / ducting is not an option, due to positioning.

i work from home so i have no real problems keeping the door open / fans blowing. but the problem with this is sleep - there is no way i can continue getting bugger all sleep (3 days so far) because of a noisy fan blowing and a blinding light 3 foot away from me. i am currently on a 18/6 veg cycle. is there any possibility i could cut this to a 16/8 cycle - i could cope with 8 hours sleep. or would this turn all my ladies hermie?

[RastaKaze]

theres a dif. between air and radiant temps.. try placing a peice of cardboard over the thermometer and measuring temps again. this'll give you the correct AIR temp. you want to maintain between 30 and 40 celcius..

[BobBong]

Yikes! 30-40 Celcius is 86-104 Fahrenheit!

Even that is still a tad to hot...I'd say you'd want to really stay in the 75-85 range....rarely going over 90...

[ukgreen]

could it be that i have a 'false' temp reading - because i have the thermometer resting horisontaly on the plant pot's. - just around 6" below the light.

i know if i had the thermometer any other place in the space the temp would be much lower, as where i have it now is possibly the hottest place. though i put it there as it is close to the plant's.

[BobBong]

Pic's speak a thousand words...

It's hard to say if this is where you should be taking the temp's or not.. as i can't really tell how large they are.

If those readings are 6" below the light...how far are your plants from the light?

what stage is she in?

reducing your light cycle to 16/8 is not a bad thing it just means the plant will go into its flowering stage sooner and slower...as opposed to staying on 18/6 and cutting straight to 12/12.

Need pics

[ukgreen]

no digi cam at the moment (lost cable) though when i find it i will post some pics.

the plant's are only 2 week's old (from seed in wet paper towel stage) and are now about 3 or 4" tall - with a 2 or 3" gap from the lamp. they are in the veg stage - i left them under 2 X 20w cfl for a week after they sprouted so as not to 'over do it' with the light.

on the light cycle matter - is it safe to just switch from 18/6 to 16/8 straight away or should i gradually reduce the light by 30mins a day? sorry if these are silly questions but being my first grow it's mainly for experience - and i want to get thing's right.

thanks for all the advice by the way.

[BobBong]

no digi cam at the moment (lost cable) though when i find it i will post some pics.

the plant's are only 2 week's old (from seed in wet paper towel stage) and are now about 3 or 4" tall - with a 2 or 3" gap from the lamp. they are in the veg stage - i left them under 2 X 20w cfl for a week after they sprouted so as not to 'over do it' with the light.

on the light cycle matter - is it safe to just switch from 18/6 to 16/8 straight away or should i gradually reduce the light by 30mins a day? sorry if these are silly questions but being my first grow it's mainly for experience - and i want to get thing's right.

thanks for all the advice by the way.

Not silly questions at all, The incremental light method isn't used by many.. i myself tried it.. and have not noticed a significant difference between it and switching straight to 16/8.. or 12/12 for that matter..

Switch away! Just don't switch back...
Once you reduce the hours of light and increase the hours of dark.. don't change back. This induces the growth of male flowers because it attempts to re-enter its vegitation stage...

As for the Temp.. it sounds like you're still pretty small ... 40watts of CFL shouldn't produce enough heat to hurt your plants.

Once the plants become large enough, the top of the canopy is where you'll need to take the temps from.. as you'll want to avoid burning them as much as possible.

Cheers, Bob.

[ukgreen]

right i will switch to 16/8.

i am now using 2X125w envirolight now. i only used the40wcfl during the sprouting stage.

[RastaKaze]

Yikes! 30-40 Celcius is 86-104 Fahrenheit!

Even that is still a tad to hot...I'd say you'd want to really stay in the 75-85 range....rarely going over 90...


Whoops, lol, thanks for catchin' that one bob, I meant 30-40 for radiant temps, 20-30 c for air..

[latewood]

On my current blueberryx grow, I 24/0 seedlings under 'bobbong's cfl's for 10 days; Switched 18/6 under 400w MH w/sunmaster warm deluxe. Every ten days I reduced "lights on" 17/7 to 16/8,15/9,14/10,13/11...I am inducing 12/12 flower 60 days from seedlings, tommorrow. All has gone well and I think that I will not see the tremendous stretching that you see from a "Dead Switch" 18/6 to 12/12...3hrs. 4oow MH then 6 hrs. of 1000w hortilux then final 3 hrs. with 400w MH. In fact; I am pretty sure I will get a shrubbery type result from this experiment*. I have tremendous amounts of big flower sites all over. I am glad I tried this...thought you might like to know, latewood
*Torog posted thread about a DJShort method/opinion and I decided to try it straight away, thanks Torog
PS I will do 11/13 after 5 weeks of flower...

[latewood]

I'm sorry, this is about temps...bro, you are gonna have to get some ductwork going...no way to keep heat down in a closed environment...goodluck...