Small Cabinet Grow - Airflow & Fan Speed

[tover]

For my first grow I'm planning to convert a cabinet into a grow box. I want to grow 1-2 small autos under quantum board style LEDs. Low odour & noise are my top priority, so I'd really like to get filtering & ventilation dialled in.

Box dimensions: 0.4 m * 0.8 m * 1.7 m, or about half a cubic metre.

After lots of DIY filter research I concluded that a standard 100mm/4" carbon filter is my safest bet.

I want a nice, quiet exhaust fan to pull through the filter and found one that's great on paper. It's sold variously as Blauberg Ducto, Vents/Winflex Quietline, Black Orchid Radial.
25db, 8 watt, 110 m^3/h

There's a 2 speed version with a 75 m^3/h mode, but it's more expensive, harder to source, and requires DIY wiring.

By my calculations, with 25% reduction from the filter the low / full speed fan would get 1.8 / 2.7 air changes per minute respectively.

• Is my filtering setup for a 0.5 m^3 cabinet with a 110 m^3/h fan pulling through a small 100mm carbon filter good for keeping odour contained?

• Is that fan a decent size, or is it going to suck too much air through my closet and cause problems?

• What's my best option for controlling air flow and environment while keeping costs reasonable? Two speed version? Socket adapter w/ speed controller? Recirculate some air?

Note: The air will be circulated into the enclosing room or possibly back into the cabinet itself. I have quite a variable environment - no air conditioning, mild & very humid winters, hot dry summers.

[Smokey]

You can use this tool just enter the details you have/require it will calculate the best option for you pal, Have A little look at this app.php/gr420-grow-calculator

Hope it helps

ATB

Smokes

[tover]

You can use this tool just enter the details you have/require it will calculate the best option for you pal, Have A little look at this...

Thanks!

[tover]

I used to grow in kitchen cabinets. I used (and still do) a 5inch fan on a variac controller. The fan was probably running at about 20%.

Quiet as a mouse.

With my quantum boards, I need about 45cm from the tops of the plants or the plants don't like it.

In the cabinets, I used an old reflector with a small 70w cmh bulb fitted at each end and I could get that literally on top of the plants.

But a QB dialled down in power you can get close to the plants.

Good luck anyway.

Thanks for the feedback! Those variacs don't come cheap, but sounds like I'm a bit overpowered and a fan speed controller should do the trick. Tempted to try a cheapo one, but have a feeling I'd regret that

If you have any model recommendations for the Variac please share.


As for dialling down a Quantum Board -- great tip. I've been wondering how close I could run those.

Does that mean a 150 watt board run at half power can get closer than a 75 watt board at full power, ie: gets me more lumens on the plants?

[Smokey]

I use one of these on my smallest people say they can make fans hum when dialled down however i personally do not notice the difference nice and cheap and does the trick imho

https://www.ebay.co.uk/itm/Variispeed-P ... rk:19:pf:0

Cheers

Smokes

[tover]

I can dial my board down and I did for when the plants are young, this is only my 1st grow with it but I have discovered I need at lest 18 inches from top of plants to board. So in a cabinet headroom will be needed to be taken into account. Same as when I ran a cob unit in the cab, the plants don't like em on top of them. That's why the 2 x 70w cmh worked so well for me in there.

But as for lumens and stuff,... I dunno. ?? I'm not technical, just go with what the plants ask for really.

I only went QB as it gets a bit hot in the basement during the summer under a 600w hps and I was having to knock it back to 250w so thought why not just run a 240w QB. ;) :D

I support that kind of thinking ;)

Will ask the QB suppliers about the distance thing. Definitely prefer LEDs, but buying a fancy light and then having problems with my setup would be a bummer. I did see a micro-grow on another forum that seemed to get pretty good results with a small QB at pretty close distances. Fingers crossed.

[tover]

I use one of these on my smallest people say they can make fans hum when dialled down however i personally do not notice the difference nice and cheap and does the trick imho

Cool. That sounds like a plan. I'll get the full speed fan and a cheapo controller to start with. Then if the controller causes problems I'll look into a variac.

The manufacturer actually recommends its own Thyristor based speed controller for that fan line.
From what I gather the cheapo socket speed controllers work on a similar mechanism.