Hi

I have started my new growroom construction (loft)

the largest tent i can fit in is a 1x1x1.8m

what size of light would be most suited to this size of tent (400 or 600w)? i will buy extraction to suit.

Also is there much difference between a 400w with a digi ballast and a 600w with a magnetic ballast?

e2a: based on 50w/sq foot i should use 538 watts, so i guess iv answered my own question sorry

400 mate. Might get away with a 600 if it's cooled (cool star or whatever).

I've got a 400w diamond in a 1x1 and just had to upgrade to 150mm extractor, as the 125 with a filter was insufficient :/ Have a look in my diary for details.

ok thanks for that, il go for a 400w with digi ballast then with a 6" ruk + cf

seen m8 :} good luck

My mate is using a tent 1m x 1m x 2mhigh. He has a 600w HPS in it.

I cannot tell you how much of a temps problem this has caused. Still not resolved fully.

The ballast is outside the tent. Using an air-cooled hood as well with a 4" inline fan.

Ambient Temps are 31 deg C , root temps are 25 deg C -
Air in vent is nearly hanging out of a wide open window - outside temp is 10 degC

We are trying to sort this so that we get ambient temp of 25 degC and root zone temp of 20 degC.

He has a 400w ballast but cannot afford the bulb! We believe this would sort the problem out.

So for you (in my limited experience) I'd do a dedicated fan to service the air-cooled hood
to reduce lamp temps max.

Good luck, let us know how you get on.

How much extraction does he have and where is the air going to?


Yeah I honestly think that's the best plan.

Personally would avoid diamond reflectors too, as mine puts down an unbelievable amount of heat!!

thanks for reply quickly



funny you should say that but i had heared them diamonds put alot of heat down so i was gonna go for something else not sure what yet tho

I've read really good things about the mini growstar on here, but they seem to have stopped making them now

Are you going to be growing sativas, indicas, sat doms or ind doms? (or 50/50 sat/inds? )

extraction is 183m3 / hour 4" inline fan - venting into the room, air coming in from outside (nearly - windowsill)

is the mini the 250/400w version of the growstar m8? i was looking at them the other day didnt realise they stopped making them

i will be growing a mix, mainly indica tho,, i would of liked a 2m tent but the roof trusses say "NO"

Yeah, no wonder you've had problems man. You need a 5" minimum for 1x1x2! Even with a 400, I think you'll struggle unless you upgrade that... and not extracting outside will only make everything harder (higher temps, less adequate air exchange, more chance of mould etc.)

Good luck getting it sorted!

You an use a 400 watt without a cool tube or something of the like. If you out in a 600 watt you will need some kind of cooling system. I think the 6** watt is better for the growspace you have.

Regarding a 400 watt electronic and a 600 watt digital... just get a 600 watt electronic ballast. The Lumateck are wuite good and they have an adjustable output level so you can run at 25%, 50%, 75% or 100% output. So as things get bigger you adjust the level. It saves on the heat at the early stages and electriity for sure. SO ultimatley you have a 150, 300, 450 and 600 watt bulb at your disposal.

Good luck dude

I would use a 600w, with probably something like a 5" intake and 6" out. 1m x 1m is nice for 600w, but it really depends on what fans you have and where the air you're moving is coming from/going to.

Lots of places getting the mini grostar back in now or shortly I believe. the mini is about right for a 600w, the normal grostar is more like 1000w.

Not sure, they're the ones that aren't massive!


Indicas and indica doms will cause less of a problem, but with <2m of height I would stick with a 400 regardless. I agree it would be worth getting a 600w ballast though... that way you can always move up to it later if you find it easy to cope with the temps

id go wit the 400 myself . . Cause 600 can be overkill in small spaces

Can always up the watt's at a later stage to suit your needs. .

Driptray

does anyone know when the mini grostars will be avaliable

...iky...?

...iky...!

I just love it when ppl quote me!

im not looking to get involved with cooling my light with a cooltube/coolstar type shade because im going to have 2 tents to kit out

i have decided to use a 400w HPS for my flower tent (1x1x1.8m) with a 4" intake and 6" extraction

thanks for all the input

600w in that space for sure. if you're having problems controlling a 400w in that kind of space, then you're doing something wrong! a high powered 5" extract and high powered 4" intake will handle a 600w with ease if set up right. set right does not mean venting into your intake space either. i have a single 5" high powered s&p with passive intakes, and i'm having to put a 700w oil rad direct inline with my intake at the moment, and i'm still struggling to get my temps past 25' with lights on. space is roughly 1x1m squared, less than 2m high, 600w sunmaster 7200k MH. air intake from outside, and exhaust venting outside also. during the summer lights on at night, with an intake temp of 20'c-25'c i never saw over 28'c.

Are you growing in a tent? If so, where is it? Outside? In this country?

Do you have a carbon filter? Because that seriously takes it out of your extraction power.

Seriously, I'm extracting up a bloody chimney and a 400w is still plenty to handle in such an enclosed space! My 5" with a carbon filter was insufficient.

if i knew i could get away with a 600w hps in a 1x1x1.8m tent in a loft with 4" intake and 6" extract i would go for it......

hmmmmm still cant decide now

With it being a loft, I'd suggest 600w for the winter and 400w for the summer.

A 6" hi power Ruck/RVK and a 400w to start, gives you the best chance of a problem free grow, get the 600w a few grows later.

i had a 600w hps in a 1mx1mx1.8 budbox with a cooltube running a 5" rvk l1 fan for ext an no intake an it was fine, kept the temps perfect throughout summer. so its defo possible to have a 600w mate especially with a bigger fan an intake.

check out my sig, that was a tent, 5" exhaust 4" intake, 600w in the summer. my current grow is just a 5" in a well insulated shed, as i said, intake from outside exhaust going outside. a loft grow is very much like a shed grow as it happens. hot as fuck in summer, cold as fuck in winter. and of course i use a cf, pretty stupid not too. a 5" S&P will flow something like 230-280m3/hr with a cf attached (410 without). lights on at night, this is plenty adequate, especially at this time of year, as i said, having to use a heater to bring temps up. if you're struggling with a 400w, then you must have either a serious airflow problem or your reading radiant heat from somewhere, or you're using a low powered 5" fan, which is no good for exhaust and a cf, as they don't build adequate pressure for good airflow with a filter

I'm with Scraglor.I think 600watts is minimum for 1m tent. If you can't cool it you aint got enough airflow. I have used 1200watts in a 1m tent(Don't ask-I just had to try it). I used an 8" out and a 6 in. No ductwork(almost) and no cf. Tent was in a caravan in summertime.(aka Oven).
Result- inside the tent was the coolest place for miles.

You can cool ANY light with enough airflow imo.If it ain't cooling the air ain't flowing.Underlighting your garden is a poor idea in my expeience.

Peace
Papa.
Forgot to say that tent was my veg space running 24/7...Buy big fans I say.

Are the new model lumateks out in the UK yet ? all I can find is the 'super lumen' model ?

Ah right, a shed is not the same as a room in a house... Maybe he'd get away with it if the loft is uninsulated.


No airflow problem... L1 125 RVK was insufficient (so that's not low powered). The 150 has resolved it

I have a 1x1x2 tent in my loft using a 600w. I'm only using a 4" outtake and passive intake at the moment. 1 6" clip on fan + small pc fan circulating the air inside the room and my temps are 25-27 Degrees lights on. Lights off it gets a lot cooler so I have had to compensate by puting in my tube heater at 15 min intervals on/off. I have a 5" and a 6" RVK fan which I can"t use until I find a way of silencing them, then I will increase my extraction as I'm in dire need to do so.

But my point is, if I can keep temps at 25-27 with a 4" out take and passive intake, why would you have problems with a 4" intake and 6" out take? Since your growing in a loft, the air that your pulling in is generally cooler than somebody who grows in a bedroom etc. So start worrying about how your going to handle the cold winter temps when lights go out

Wont be downgrading to a pathetic 400w in the future i tels ya that much.

Either 400W or 600W is plenty though mate.

Enjoy setting everything up

New model just has variable power more a gimick imo.

600 imho, always buy a bigger fan than you think you need and slow it with a controller, I made the mistake of buying a 100mm and having it on full tit all the time, moved to 200mm and it covers all the bases all the seasons.

Woody

or he takes the air from directly outside. although as i've said, the shed is WELL insulated, 6 inches of insulation, then the shed is partitioned, to make a room within the shed. the actual grow section intakes air from the other section, which gets fresh outdoor air. i then have to heat this air to bring temps up, temps measured at intake are around 18-20'c. so not that different from intaking from a house. dn't see why an attic is any different if you're venting outside

i wanna know how you're reading your temps? because a 125mm L1 should piss all over a 400w lamp if you have adequate intakes/exhaust root

Taking it at canopy level with a hydrogemeter, but the fresh air aint coming from outside, it's coming from inside, so it's nowhere near as cold. It's definitely an accurate reading, it is pretty damn hot in there, even with a 150!

It's a diamond reflector too, and it puts down a hell of a lot of heat.

I think even a well insulated shed is going to be lot cooler than the little cottage i'm in, or an insulated loft. I used to grow in a loft with no insulation and a 125 was adequate for 1000w in the winter and 600w in the summer, although that wasn't a 1x1 tent but a very airy 1.2x1.2 construction I put together.

thanks for all the input ppl i really appreciate it

im going for a 4" intake and a high power 6" extract should keep things cool enough in a 1x1x1.8 tent if i use a 600w hps

i can move the intake ducting so it pulls air from inside the grow space or inside the loft space or from the vented soffit so i can keep dialed into keeping the temps rite

the diamond may 'put down' a lot of heat, but it's radiant heat, (otherwise it would go up!) and canna can take radiant temps of up to 50'c with ease. so the diamond shouldn't be a problem in that respect. my intake temps are, like i said 18-20'c so again, no different than if i was intaking air directly from inside my house. doesn't make any difference at all that my grows in a shed. the room is thoroughly insulated so it's down to the intake temperature against airflow. which applies to all grow rooms. with a 125mm i can keep my grow within 10'c of my intake temps, which is actually quite poor, as with really good airflow you should be within 3-4'c of your intake temps. so as before, unless you're either getting a false radiant heat reading, or there's something seriously up with airflow, a 125mm should cope with a 400w a piece of piss. you don't mention an intake fan? so a first guess would say intake area is too small, or do you have an intake fan?

I'm not sure how you differentiate between radiant temps and non radiant temps (how can you tell, or do you just mean if you take it from somewhere beneath the light it's a radiant temp? In which case, where does the 3-4C difference come in?) but there is no doubt it was too hot for them before I enlarged my extraction, no doubt at all. I originally had every single door, window and flap open on the tent and it was still 31/32C at the canopy. The leaves were curling inward, and the plants were very unhappy. I've always taken temps at canopy and never had anything so high as that before (certainly not when I had a 1kw in the loft, as opposed to the relatively sealed purpose built tent in a normal room).

I was using passives, but since I upgraded my extraction I've split the old extractor fan in two using a T piece so that half the air is flowing directly over the light bulb and the other half is going in at the bottom of the tent. My canopy temp is now 27C at lights on (this is with a 150mm extractor instead too) and the whole tent closed up. I also replaced the HPS with a MH, as I finally had enough of a handle on conditions to be able to do so...

radiant heat, is heat radiated from the light, i.e. infrared, or heating caused by lightwaves themselves as they're absorbed by something solid and convert into heat. what we want to measure is ambient air temperature, so your thermometer needs to be out of view of the light, with a good airflow across it. so it can be below light level but needs to be shaded with something highly reflective, and not be close to what's shading it, as this will re-radiate heat and give a false reading also. where were the leaves curling? at the top of the plant? could it simply be a case of too close to the lamp? how close was the lamp, could just be too much radiant heat, as there's still a limit to this, IR will burn your plants and people do often complain about diamond reflectors causing this, but this requires moving your lamp further away rather than upping extraction, also having a fan blow across the top of your plants wont help, because of course, you can't blow infra red away from the tops of the plants. but quite likely you're totally right, and ambient temps were just too hot, were your lights on in the daytime? as i said earlier, you'd need to run your lights at night. hence the 3-4'c difference thing. a 5" fan should be able to keep your room within 10'c of your intake temps with a 600w lamp. so if your intake temps are around 20'c (ambient indoor temps in the daytime obviously lower at night hence my need for a heater) then a 5" should cope ok, and with a 400w should cope easy. how was the air getting into the room the tent was in if you were using passive intakes? as having a tent in a room with all the doors and windows closed, even if your venting outside via ducting, the passive area into your tent may be large, but the passive area into your room is tiny, so again you're creating a bottle neck in the system and your flowrate will be crap, all the cracks and what not around doors, wont add up to anywhere near 7 times the area of your extraction fan, yours was in the attic though? so should have plenty of gaps around the eaves?. a really good extraction setup should be able to keep your temps within 3-4'c of your intake temps, so you should be fine running in the daytime in the summer (most of the time, obviously really hot days you cant make your temps any lower than your intake temps) but at this time of year, it shouldn't be any worry whatsoever. maybe you have your house a lot hotter than average? i used to share a house with some bird who had the stat set to 26'c then moaned like fuck when her heating bill was huge and i wouldn't help pay for it when i did my indoor grow, in my sig, i had my fans slowed way down and kept temps under control easy, and this was in the summer, of course an attic in the summer gets way hotter if it's not properly insulated..

either way, it's always good to get a bigger fan and slow it down than have a small fan on full whack. a high power 5" and 4" intake should cope with a 600w and easily cope with a 400w imo though