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Looking for input on a closet build

djimb

Active member
Veteran
I'm in the planning stages of my new grow space, and I was hoping to get some input on my ideas.

I'll be building in my basement, where the temperature stays consistently at about 50F (10C). The lowest I've seen it get to so far is 48F when it's below freezing outside. I don't have a plan for additional heating just yet, but I figure I'll cross that bridge once the structure and lighting are set up. I'm hoping the heat from lights and possibly the use of a seedling mat might help keep things appropriately warm in there.

I plan to build a closet with two separate spaces behind locked doors to ostensibly serve as a tool/spare part storage space, with one side serving that purpose and the other side housing the grow.

The basement ceiling is ~6.5ft high (just under 2m). I was thinking 6ft would be a decent height for the closet. I would like to have a space for veg (seedlings/clones), males/open pollination, and a larger space for flowering out selected females. For these purposes, I'd like to use heavy duty 27gal totes for the veg and male space. For those I would like to use screw in LEDs or something similar with a low vertical space requirement. Remote ballast PLLs might also be an option. For filtration, I was thinking of individual, small carbon filters on PC fans.

The dimensions of the totes are 15.25in(h)x28.25in(d)x19.25in(w) (~39cm(h)x72cm(d)x49cm(w)) with a volume of 3.8ft3, using roughly the same dimensions for width and depth, this gives me about 3.5ft of headroom for the larger flowering space, with a volume of 13.2ft3

I'd love to use a 315w CMH for the larger space, but for now, I have an old Mars Hydro LED panel that I'll be using.

The thing that I'm having the most trouble nailing down is intake/exhaust for the whole space. I'd like to keep both cost and odor low, and I'm debating between exhausting to the room or building a void in the back of the closet to act as a plenum to recirculate air, or a small lung space that would allow fresh air and exhausted air to mix and diffuse out the back. Alternatively, I could just run a passive intake through the bottom of the closet and exhaust straight out the top. The first option would essentially act as a small sealed room and would most likely require CO2. The second one would also be more discrete, as there would be no noticeable breeze. The last option would probably be the easiest.

regarding fans, I'm unsure of what I would need for a space like this. PC fans seem like they might be the most quiet, but they may also be inadequate for the space

I'd love some input on this plan. If any of you see problems with it or have ideas of how it could be improved, I'm open to suggestions.

Also, I'm working on learning to effectively use Google Sketchup, so I'll hopefully have some basic 3D models to post up and illustrate what I'm talking about.

Thanks!
 

Jellyfish

Invertebrata Inebriata
Veteran
One thing to consider as far as temps go- your lights aren't going to be on 24 hours a day, so what is going to keep things warm when it's dark?
 

djimb

Active member
Veteran
That's a good point. The thought of staggering light cycles in the totes occurred to me, so that a pll balast would always be running and therefore generating heat, but I don't know how much heat they generate. I'll read up on that. I've also considered foam board insulation to try to retain heat. Once it's built, I'll give it a dry run for a week or so to get a feel for the temps inside. If I need to, I can always get a small space heater or possibly some heating wire that would normally be used for heated greenhouse beds. Something else to look into.

Thanks for pointing that out!
 

Jellyfish

Invertebrata Inebriata
Veteran
"Alternatively, I could just run a passive intake through the bottom of the closet and exhaust straight out the top." That is what I'd do. In a space that small, a passive intake is fine. And like you said, easier, and if done right, quieter.
 

Lemmiss

Member
You are lucky you have a problem with cold, and not with heat. Generally 1 degree cold approximately costs double in energy than 1 degree warmth.

With that being said I think that, if possible, you should invest in a small heating fan/element since maintaining an as possible stable temperature is important for, and greatly affects your yield. If you could just maintain 20c/68f or somewhere around there it would be great. if you have good insulation, and a larger waterreservoir(or any big volume of any-something leading heat) inside the growarea it could work somewhat as heat storage storing during day, and releasing during night(lights off), you probably too small for this though. I belive since you so small it will generally be hard storing temperature, and that you'll have too produce heat during lights off.

Also concerning your climate, I'm not sure, but I do belive a pc fan will have trouble/being too weak to draw enough air through any _effective_ carbon filter(An _effective_ carbon filter for _smell_(not same as for smoke n' stuff)) will also need some volume/take up space). I recommend you get a small version of what I think is called an "in-line tube fan", looks kind of like this:
https://www.google.se/search?q=In-L...UICigB&biw=1024&bih=623#imgrc=Rr5v_gBAxfzt_M:
Could easily be fitted with a carbon filter as well.

A tip for getting a quiet ventilation can also be to get a bigger fan than you need, running it on lower than max speed, that's at least how I do it.

Anyhow, if I were you... I don't think that space will give _too_ much smell. I think one of the more expensive/medium-priced ozon-generators(There are a lot of low-priced crap of these who promises a lot but does NOTHING!) could take care of that problem in full, they're pretty effective. I'd get one of those. No carbon filter. I'd do the ventilation using pc-fans. Also fit a small heating element running it when lights are off.

An interesting alternative considering heating would be to always grow from seed. Do one grow for seed and you'll have seed for a lifetime. But your grow must be of an "automatic"-strain. Then you just keep the lights on 24/7 giving you all the heat you need :)

Also, concerning smell... there _are_ varieties that smell very little compared to most.
 

djimb

Active member
Veteran
That is what I'd do. In a space that small, a passive intake is fine. And like you said, easier, and if done right, quieter.

So assuming that it's better to heat the air coming into the passive intake, I might keep a small space heater in the utility side of the closet, set up on a timer. I could also exhaust the air from the top of the grow side back into the utility side and put some holes in the back to allow air exchange with the rest of the room. Does this sound reasonable? Or is it needlessly complicated?

if you have good insulation, and a larger waterreservoir(or any big volume of any-something leading heat) inside the growarea it could work somewhat as heat storage storing during day, and releasing during night(lights off), you probably too small for this
though.
[...]
Anyhow, if I were you... I don't think that space will give _too_ much smell. I think one of the more expensive/medium-priced ozon-generators(There are a lot of low-priced crap of these who promises a lot but does NOTHING!) could take care of that problem in full, they're pretty effective. I'd get one of those. No carbon filter. I'd do the ventilation using pc-fans. Also fit a small heating element running it when lights are off.

Also, concerning smell... there _are_ varieties that smell very little compared to most.

While I really like the idea of thermal mass and passive heating, I think you're right. The space is too small, unless i built it with brick, and I'm no mason.

I like the idea of using an ozone generator too. I've read that they're good for fighting mildew problems in humid basements, so I would have a legitimate reason for having one in their anyway. The same can be said for a dehumidifier, which I anticipate I'll need in the summer.

Thanks for all the suggestions! I'll look into the fans you both suggested as well.
 

Jellyfish

Invertebrata Inebriata
Veteran
'space heater in the closet' doesn't sound like a very good idea. Is it an indoor closet? Can you cut a passive intake from the heated part of the house?
 

djimb

Active member
Veteran
'space heater in the closet' doesn't sound like a very good idea. Is it an indoor closet? Can you cut a passive intake from the heated part of the house?

Another good point. The space heater I was looking at was tiny and meant to basically act as a handwarmer on a desk, but a fire hazard is a fire hazard.

The room is a separate part of the basement under the porch. It's maybe 10'x6' (I'd have to measure to be sure), and the walls are cinder block. There's no easy way to tap into the central heating for the house, or to cut a hole to a heated room above it. 50f is fine for me to work in, and using a space heater to bring ~390ft3 of air up 20 degrees seems like it may be a pretty significant energy draw.

I'll look into the safety of heating wire. The kind used to defrost roofs and gutters should be designed for low temp increases and contact with water.

Thanks again!
 

djimb

Active member
Veteran
A quick look at soil heating wire seems promising. It would require a 2-3" bed of sans under the pots, but in an enclosed space, I imagine enough heat would radiate up to keep it relatively warm at lights off. I think seedling heat mats would probably achieve the same ends in the totes.
I'm still curious what kind of heat can be utilized from the lights themselves, and whether staggering the light cycles might help to balance the overall temp in the cab.
 

coldcanna

Active member
Veteran
50F might be fine for YOU to work in but the plants will not grow properly. Anything below 65 and there growth slows dramatically and yields tank. To start with your using low watt lighting so you really won't harvest anything. Not knocking you, I have done unheated basement grows with 1000 watt hps in similar space and even with that amount of light and heat the yield barely justified the power bill and time put in. You should look at ventless propane heaters. You could get set up for under $200 and they work great plus free co2 for you
 

repuk

Altruistic Hazeist
Veteran
PLL ballast won't heat up that much the space at those temperatures.

There are safe ways to heat if you're concerned, in addition to heating mats, look for greenhouse tube heaters, I've seen they up to 250Watts which could be suitable for placing inside the spaces.

Additionally, I'd build the spaces using climate isolating materials to ease keeping a constant temperature.

For air movement, I'd use a proper inline fan, there are some really low on noise, RVK (Sileo) is known for this.

As you have space, you could also build a silencer box/cage for it. From past experience, ventilation (intraction & extraction) is not an area where you may skimp on.
 
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djimb

Active member
Veteran
50F might be fine for YOU to work in but the plants will not grow properly. Anything below 65 and there growth slows dramatically and yields tank. To start with your using low watt lighting so you really won't harvest anything. Not knocking you, I have done unheated basement grows with 1000 watt hps in similar space and even with that amount of light and heat the yield barely justified the power bill and time put in. You should look at ventless propane heaters. You could get set up for under $200 and they work great plus free co2 for you

I was only trying to say that I'd rather heat the air in the cabinet alone, rather than the air in the room the cabinet is in, as that would involve a lot of wasted heat/energy. I'm thinking that radiant heat from soil heating cables and heat mats might be sufficient, but I could be totally off. I'd like to get everything built and wired before trying to fully tackle the heat problem, just to get an idea of what kind of temperature increase I'll need. This will be dealt with before any seeds are germinated.

I like the idea of free CO2, but in a small, enclosed space, I'm not sure a propane heater would be safe. I'll look into it though.

I'll agree that the lights I'm talking about are relatively low wattage. This is a personal hobby grow and I don't smoke that much, maybe a gram a week, so high yield isn't critical. Still, I'd like to find a balance between energy cost and yeild. In a maximum space of about 24ft3, what wattage would you recommend? 1K seems a bit much for that space, but I'm open to a small HID or building an LED fixture from COBs. I might build small COB fixtures for the totes once I get them put together, but I'm also considering an initial run in the full space. I'm getting antsy and I just want to build.

Thanks for your thoughts!

PLL ballast won't heat up that much the space at those temperatures.

There are safe ways to heat if you're concerned, in addition to heating mats, look for greenhouse tube heaters, I've seen they up to 250Watts which could be suitable for placing inside the spaces.

Additionally, I'd build the spaces using climate isolating materials to ease keeping a constant temperature.

For air movement, I'd use a proper inline fan, there are some really low on noise, RVK (Sileo) is known for this.

As you have space, you could also build a silencer box/cage for it. From past experience, ventilation (intraction & extraction) is not an area where you may skimp on.

I'll look into the tube heaters as well when I get everything else set up.

I plan on insulating the grow side of the cab. I've seen rigid foam used a lot. I'll have to look into how well it performs at keeping heat in and smoothing out temperature swings. Do you have any suggestions regarding materials?

I do want to make sure I overbuild the ventilation. right now, I'm looking at a 4" fan at about 190cfm and probably slowing it with a fan controller. From what I've read, to get an air change every three minutes in 24ft3, I'll need 8cfm, but the added pressure from a carbon filter would require 10 times the cfm rating, giving me 80cfm. That's about half speed for the fan, and I figure if it's relatively quiet at full speed, it should be near silent running at half power. I'll also look into building a silencer box. I'd love it if you could stand next to the cab and have no idea that there was anything going on inside it.

Thanks everyone for your input. This is all really helpful!
 

Lemmiss

Member
There are very small electric heaters, as small as a fist, which produce heat but dosn't get so hot that it burns. Not "space heaters", Enclosure heaters! :)

https://www.google.se/search?q=ENCL...AUICigB&biw=931&bih=566#imgrc=mRTgLSwfmwzPKM:

If you're into some simple electronics you could take any small heater(anything producing heat with "resistor characteristics") and regulate its output with a solid-state relay, turning it on and off relatively fast to produce the amount of heat you want. Even a toaster could work fine :)

Otherwise I think an easy solution would be to use infrared lights. The plants can't see that light, but it solves two things in a blow for you. It produces heat, and light you can see during the "night", but doesn't disturb the plants. Don't know what those lamps could cost though. Probably cheaper than any suitable enclosure-heater
 

Lemmiss

Member
Oh, I must add. All this might just be babbling, but I feel it could be good info anyway, and it can't hurt to know can it? :)

Since you care about the energy and talked about fan on half speed. Be aware which technique you use to slow down the fan, since some principles is "burning" the extra energy up to max for slowing. That could beneficially be burnt for heat during the night. But during day it wouldn't be as nice, and would only cost wasted electricity, then instead maybe for half speed u block half of the ac wave with a diode(cheap solution), or at least not "burn" the energy. I guess this is overkill, but I at least would advise a technique for slowing which doesn't mean burning the extra energy anyhow.
 

Jellyfish

Invertebrata Inebriata
Veteran
In a maximum space of about 24ft3, what wattage would you recommend? 1K seems a bit much for that space, but I'm open to a small HID or building an LED fixture from COBs. I might build small COB fixtures for the totes once I get them put together, but I'm also considering an initial run in the full space. I'm getting antsy and I just want to build.

In answer to this, question, I have worked in this size space, and I would say 250-400 watts would be appropriate. There is such a thing as too much light.
I personally like LED's because they work great in closet grows, AND because they run pretty cool.

I was running 400 watts of LED light in a cab about the size of yours, and it was working great. When I decided to double up, and add a second 400 watter, that's when everything went to hell.

I got rid of one of the units for the next run, and I'm back to the success I was having before.
Hope this helps.
 

djimb

Active member
Veteran
There are very small electric heaters, as small as a fist, which produce heat but dosn't get so hot that it burns. Not "space heaters", Enclosure heaters!

If you're into some simple electronics you could take any small heater(anything producing heat with "resistor characteristics") and regulate its output with a solid-state relay, turning it on and off relatively fast to produce the amount of heat you want. Even a toaster could work fine

Otherwise I think an easy solution would be to use infrared lights. The plants can't see that light, but it solves two things in a blow for you. It produces heat, and light you can see during the "night", but doesn't disturb the plants. Don't know what those lamps could cost though. Probably cheaper than any suitable enclosure-heater

Thanks for the link! Some of the smaller, less expensive enclosure heaters look to be pretty simple: just a heating element surrounded by a cage with a built in thermostat. I imagine a ceramic heat lamp for reptile with a cage built around it might work just as well. I'll have to look at schematics for a simple thermostat circuit, but at the very least, a timer plugged into a gfci might work well enough, and as you said, it would be quite a bit less expensive than a prefab enclosure heater.

I also appreciate the advice about controlling fan speed. I'll have to look into my options.

In answer to this, question, I have worked in this size space, and I would say 250-400 watts would be appropriate. There is such a thing as too much light.
I personally like LED's because they work great in closet grows, AND because they run pretty cool.

I was running 400 watts of LED light in a cab about the size of yours, and it was working great. When I decided to double up, and add a second 400 watter, that's when everything went to hell.

I got rid of one of the units for the next run, and I'm back to the success I was having before.
Hope this helps.

That is really helpful, thanks! I'll be starting out with a mars hydro 300w, which only actually draws ~165w, but I plan to start work on the cob lights in the next 6 months or so.
 
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