400w in a Small Space?

[wakislander]

Hi Everyone,
I recently had to revise to a smaller setup for the time being. I am wondering if I can pull of a 400w in my space. The tent is only 3hx2.5lx1.5d (feet). I currently have 6 sprouts vegging (3 fem, 3 regular) so I will end up with anywhere between 3-6 plants, and would plan on running this same amount in future runs. The plants would flower in 1-2 gallon pots. Do you think I could run a 400w in my size grow space, assuming all other factors are under control.

I have an overkill inline fan that currently runs at 5-10%% with the 125w CFL I use for vegging. The max CFM for the fan is 200, which is a lot for such a small space. I would consider getting a cooltube to help temp issues, and am also researching vertical lighting more to see if that could be beneficial. Oh, and I would certainly consider getting a dimmable 400w.

My main concern, other than heat, is if the current tent is just too small to run a 400w in terms of plant size. I plan to veg for around 4 weeks, training, topping, LSTing. Would go with a SCROG no problem. Would I be able to control the plants in such a small space with a 400w? The reason I'm considering a 400w so much is because I want to maximize yeild and would move to a bigger tent in the future, in which case I would use the 400w and use my current small tent for vegging. My only HPS light is a 150w at the moment and if I can pull of a 400w instead, I'd go with the 400. Same thing goes regarding the potential for a 250w - the price difference between a 250w and a 400w is so small, I'd go for the 400w in a second, granted I could pull it off.

What do you guys think? Dimmable 400w in a 3hx2.5lx1.5d tent, with ample ventilation, 3-6 plants, potential SCROG.

 

[Budwhyser]

I don't think it would be a problem, but dude you're going to have to experiment and fuckup a few times to figure what works and what doesn't. Maybe try one or two plants as an experiment and adjust your program as nec.

 

[3dDream]

Too small. My 250 W can be too much for a plant at 6 inches.

 

[wakislander]

Thanks for the responses Budwhyser and 3dDream. 3dDream, could you clarify by what you mean regarding the 250w being too much "for a plant at 6 inches"? Is that a plant that is 6 inches tall, or the light being away from the plant by 6 inches? I will not be using this light to veg.

As mentioned, other than heat, the space I have concerns me. I'm asking myself if I will be able to keep the canopy a good 8-12" from the light, using a screen. What is the safest distance I can keep the canopy from the 400w, do you think? Having 36 inches of vertical space, that would mean - light 5-6", leave 8-12" from light to top of canpoy - that cuts me down to attempting to keep the plants no more than 18" tall (with pots!). Will the 400w just end up bleaching my plants in such a small space?

I have no problem experimenting and taking time to dial the set up in. I also have no problem with going with 1-2 plants in the future, heavily SCROG'd. Also, I would go with the DIMMABLE option over a straight up regular 400w. I'd really like to take advantage of a 400w to obtain dense, thick buds, instead of light, more airy nuggets I get from the 150w.

Thanks again for the help and suggestions.

 

[mpd]

Nope, check out my construction thread on my cabinet and my lighting upgrade thread in the Design & Construction forum. You need to go with fluorescent lights and based on your dimensions I would suggest using U-bend T8s like I used.

 

[3dDream]

wakislander - Yes, I was talking about light burn.

 

[wakislander]

Hi Everyone,
Thanks again for the responses. Regarding my size tent, I know people who run 250w HPS with no problems in the same tent/space, so I really don't think it is limited to just CFLs. I have run 250w in a very similar space, although different tent at the time, perfectly fine. And this was without being able to vent exhaust into a separate area than the tent.

I've decided that I am going to upgrade to a slightly larger tent when the time comes so I will not be so limited on space. I will also be able to vent 100% out of the closet to a separate area, which should help control temps. Thanks for all the thoughts!

Any thoughts on veg time from seed? I was planning on going 4-6 weeks. I will have 5ft vertical space, but would also like to keep the filter and fan in the tent above the light so all there is outside is the exhaust ducting. Plan on having 3-6 girls in 2 gal grow bags for flowering. Hoping that going with 2gal over 3gal will help me control plant height, as well as training and topping. Would like to shoot for 4-6 zips total on first run of this setup.

 

[mpd]

5' of vertical space is plenty for an HID grow. Maybe a vertical kool tube? I have used a 400 watt vertical kool tube for years and gotten acceptable results. Four plants grouped around the kool tube should do the trick. Spin the lids every other day and down the road you go.

 

[VerdantGreen]

Dimmable 400w in a 3hx2.5lx1.5d - i think you could just about do it - but you would have to be absolutely on top of the training etc. very little margin for error. you'd probably have to turn it down to 250.

VG

 

[hush]

I use a dimmable 400w in my 2' x 2' tent, and I never dim it. I'm using an aircooled reflector being exhausted by a 6" duct booster fan. It can be done. I also only use 3 ft of vertical space, because I have my flood table sitting on a 2' tall table inside of the tent. So yes, it can be done. My temps are only 3 degrees above ambient.

 

[mwz]

I've used a 400w (non dimmable) in a wardrobe easily twice the size of your tent. I found that keeping the temps low in summer was challenging. In winter it was less of a problem. There are a few ways to get around the temp, such as good ventilation, a portable air con or air cooled light holders.

How does the dimmable light work? Can you restrict the wattage or the like? i.e. the amount of light the plant receives? Sounds cool!

 

[Snook]

No problem w 400w (dimmable), if you can kep it cool (<80F).
I'm running naked 1600W (1K+600) verticle HPSs in a 4.9x4.9x6.9 tent. the room the tent is in, 10'x12', is central ACed (72F), additionally, there is a 12K 'window shaker' AC (67F) cut into a wall. Tent temps at 1600w go to 81-82F at these settings at 1200w, temps are at 77F. SCROG. with 2 plants, same strain, til you get your environment right.

 

[mpd]

Why buy a big HID light and then dim it? Hmmm.... Seems wasteful...

 

[hush]

Not really. If you think about it, when people are just starting out, or need to use a small space, it makes better sense to buy a 400 watt setup and then dim it, rather then buy a 250 watt setup that costs the same price (or even more in some cases). At least the 400 watter might eventually be able to run full blast someday, if circumstances change. But that 250 will always only be 250.