Hi all, I've been trying to put together a grow for the past few months, but due to various problems have had to put it off until now. I am planning to grow in my garden shed (Martin Fowler style, well not quite...) and have done it up a bit and built some cupboards for my other new hobby homebrewing.

I had planned to have one cupboard (3'H x 6'L x 2"W) for the grow, but due to the influx of nosey neighbours and inlaws after free beer, I have had to rethink my plans.

So I've decided to have a stealth box within one of the cupboards, but it has to be almost completely silent, so if someone wants to look inside, all they will see is a normal cardboard box full of "brew supplies." Otherwise, perhaps I can have a kill switch by the door to cut the fans when someone comes to have a look.

After doing some research I have come up with the following design and would appreciate any advice or comments on what I can do to improve it.

My biggest problem at this time of year is going to be the cold, so the insulation in the box should at least help with the temps. I have also toyed with the idea of having a green 40w lightbulb come on after lights out to keep the ladies warm and to allow me to poke around inside without worrying about light leaks.

Anyway let me know what you think

-looks good, I'd go for envirolites - and a Soler & Palau 160td fan (about £50 from TLC) - good and powerful, and frighteningly quiet (only18db) - two speeds, or you can use a speed controller - and unless you're made of money and have a lot of space, roll your own filter! - the commercially available ones are HUGE! If you want a cheap and safe heater tlc do a 60w tubular for about £12 - rig it up with a simple room thermostat - no frost probs - nice and compact too - a 2" metal tube about 15" long! - Good luck, you'll get there!

Cool, thanks for the info. I've already got a 250W hps lowbay that I need to convert and a bake-a-round for the cool tube, so that's not a problem.

As far as the fan goes, I've had my eye on one of those inline duct fans, but they are quite pricey. Is it possible to rig up a couple of computer fans to do more or less the same job? Perhaps one on the intake of the cool tube and another one pushing the air through the filter. Or is it better to just spend the extra money?

Thanks for the tip on the heater, I think I will definitely go for that option over the lightbulb. Could you recommend a good thermostat to use with it though. I don't know much about them, but it sounds like the TL RT16 would do and it's only a fiver. Here's the link http://www.tlc-direct.co.uk/Main_Index/Hea...tats/index.html

Also would there be any problem having the heater in with my ladies and would it be better to mount it on the ceiling, or perhaps underneath them to warm the air as it comes in? I was planning to have them on a sliding shelf/floor as I hope to go scrog once I get some mums. Though thinking about it, having an electric heater underneath, when they have just been watered and are dripping everywhere might not be such a good idea...

I'd definitely go for a duct fan - they are the only way if you need the "suck" to overcome the resistance of a carbon filter - the S&P one is reasonably priced, and really is a lovely piece of kit. As to the tubular heater - mount it 3" up from the bottom on the wall (it comes with brackets) - although it doesn't come sealed, a bit of silicone would render it totally waterproof - as they are, they'll take the odd splash - definitely put it low down as heat rises! The thermostat looks fine, mount it about a foot from the top of the cabinet, and make it a silver paper "hat" so it doesn't get overheated from the lamp!
I glibly said "roll your own filter" - it really is easy, somewhere on the site there's instructions on how to remake a bus air filter - my suggestion is to look at the stuff you can get for cooker hoods - thin sheets of carbon impregnated filter - if you sandwich some activated carbon (aquarium shop) between two layers, giving a sandwich about half an inch thick - you need a reasonable surface area - a couple of square feet - it works well! (difficult to describe without pics, but here goes!) - get a panel that fits the top of your cabinet - half an inch thick - cut holes through the panel to give a couple of sq ft of hole - staple cooker hood stuff over the bottom of the holes - fill up the holes with carbon - staple another layer of filter over the top - bingo! - a "panel" filter - use this panel to give you a "false ceiling" to the cabinet - giving a top chamber about 7" deep - shove your fan in there - connect the outlet end to some ducting, and run it to a vent hole in the side/back of the cabinet - make sure the top chamber is well-sealed (bathroom sealant and duct tape) - then air is drawn through the filter from the growchamber - through the fan, and thence to outside - in your case, I'd suggest running the duct into one end of your cool tube - then another bit of duct to outside! That way you're not sucking hot air through the fan, which isn't particularly healthy for it! If I've described it right, the airflow should go - cold air in at base - pongy air filtered by carbon - sucked through fan -then through cool tube picking up bulb heat - to exit!.
Hope it all makes sense!