Who uses a crawl space?

I am in a new location with a huge "crawl space". There is around 6 feet of height from the dirt floor to the floor joists. After retiring my 3rd grow cabinet around a year ago, I swore to myself I was not going to bother growing again until I had the means to set up a tent or framed grow room. This amount of space available has me itching to unpack my equipment.

First concern:

When I first checked this area out, it was late spring and there was ~4" of water on the floor. On further inspection, it seems as if the high water mark is at about 6". To deal with the probability of water, I plan on setting up a temporary floor using plywood and cinder blocks. The only remaining issue with the water is humidity. My thought is to set up a sealed tent, and run the intake through a dehumidifier. Even if I can effectively lower the humidity of the air through the inlet, this sounds very inefficient. It would likely run constantly. Another thought is to cycle the exhaust fan, but that's not particularly desirable. Does anyone have a better idea?

Secondly:

I'm not positive on what the ambient temp is in a crawl space during the summer, but I kind of doubt it will be above 60. Am I going to have to run a heater at night to keep the temperature swings under control? Also, I would like to be able to exhaust the tent into the surrounding crawl space. My hope is that the crawl space is large and cool enough that it would still allow for fairly cool intake temps.

Does anyone have experience growing in this type of environment?

Well water in a crawl space is a very bad thing. it will rot floor joist out etc. If you own the place you need to fix it. The problen I see is 1st off water and electricity dont mix. 2nd off if you built a platforn thats 8 inches of space your loosing. lights if hps/mh you will only have 2-3ft of grow space then account for pots etc you have a little room height wise and may be alot of problem due to mositure humidity etc what is the humidity in the home I bet it will be alot higher is summer as irsbhot and water evaporates and up into the floors etc if you rent tell the landlord and see if he will fix it and then you could be golden

I've got a couple HID grows under my belt. I have more experience than I like to think about growing in small spaces, and this space will work like a dream for me. I'm also handy and smart enough to deal with the water/electricity issue.

The floor seems to be sound, so the large height down there must be enough to prevent rotting. The landlord is not interested in fixing the periodic presence of water, so I will gladly deal with that in exchange for him staying far away from my place.

So under the assumption I'm qualified to do any electrical/plumbing/fabrication work required, does anyone have any tips to help me create a good environment to grow in?

Edit: Reading back I sound a little harsh. I only meant clarify my situation. Thanks for the quick response aznohaze!

Sump pump are very cheap and easy. Just dig a whole for the water to gather and place your pump in there. Then your method should work easier and help recover the $100 investment. Also keeps landlord away. The heat your lights throw off into the crawl space should help keep it dry in return keep the humidity down.

Good point. Can't believe I hadn't thought of that. I even have an open u bend used for the water heater purge. I dropped in last night and was surprised that it was about 70 degrees down there and about 50% humidity. Not sure what the temp will do this summer, but if I can keep the standing water away humidity may not be too bad.

If you can find free fill dirt build ut uo around house landlord might take it off rent and would be a double bonus for you but yeah if you can do it ob your own with out getting help I would do it. Props to ya also a sump pump is a good idea I wiuld barry a trash can etc in ground for water to eneter to keep the home beconing full of mud and pump clogging

If you can find free fill dirt build it up around house and landlord might take it off rent and would be a double bonus for you but yeah if you can do it on your own with out getting help I would do it. Props to ya also a sump pump is a good idea I would burry a trash can in ground with pump in the can for water to enter to keep the crawl space filling with water and the pump clogging full of mud as a sump pump is normally on or in a convrete hole

Well I dropped in again and re-evaluated the situation. I found good and bad.

I was first surprised to find it was almost 75* down there! Turns out there is a vent for my HVAC system that is partially open down there. I have closed the vent to see how far the temp drops. I was even considering a sealed grow just to take the humidity issue out of the equation. This is a great find; after furnace season is over, I can pull air (air conditioned in the summer) from the living area. Should have good temp control and air quality, as well as lower humidity. Hopefully I can just vent within the crawl space. I don't really want to cut another hole.

Because I dont want to have to dig an obscenely deep well, I am going to build a platform on higher ground. This is only going to allow for a 4ft height tent, but I can fit lights and ventilation equipment between the floor joists.

The plan is to run 2 plants flowering under a 600w in a 5'X5' wood framed tent. I am building this large tent so I have room to place equipment and work. The 4' ceiling will be rough enough, so I might as well leave myself some extra room. This additional volume should also help keep temperatures stable. Ill build this room to test everything out, and then likely build another one right next to it for more workspace and vegging under a 400w and 150w light. All these lights will be air cooled with a duct blower. Once the AC turns on, I hope I can use my 400CFM active air fan to vent both rooms. The periodic blast of cold air should be enough to keep temps under control, and the lower flow might let me use a humidifier/dehumidifier if I need to. But I am likely going to need a second fan at some point.

My top requirement for this grow is the ability to let it run itself for a few days. I want to build two 2X 3.5 gal bucket RDWC systems, one for flowing and one for veg. Once I get it dialed in I hope to be able to fill a reservoir with nutrients and have it top off (and hopefully control ph) for a few days. Still uncertain if I am going to need a chiller for this system, but It might be cool to burry a copper coil heat exchanger since I have a dirt floor. Gotta find that silver lining.

Its pretty obvious where the water comes in from. I am thinking of digging channels from these locations to a buried bucket sump, and laying plastic down so the water easily drains and stays out of the soil. On the flip side, maybe if I am running my intake from upstairs I don't care about the humidity in the crawl space, and I don't need the plastic.

Lots of thinking out loud here...

I use my crawl space, 5 foot high. But, I don't have a water or moister issue. Since, you have water down there in your crawl space.. It's a No Go.
Constant Moister = Mold

Just because the crawl space is moist doesn't mean the grow room has to be moist. I just need to isolate it. By the time the moisture down there is rising I will be pulling air from my living area.

What's your set up like?

Just a thought. If your in the US and you get standing water in that space the landlord has to fix it as that standing water is a health hazard and if the city found out he would be in deep doo doo. He would probably get a chance to fix it then if he didnt they will condem the house and yank his renters license. You need to see about fixing that as your putting yourself at risk with the air quality as its a mold breeding ground and it will have moisture soaked into the floor above. Nasty black mold can kill you quickly.

Like Jimmer said.

I would not try to anything until I got a sump pump in. Find the lowest spot in the crawlspace. Dig a hole about a 12-15" deep and a couple feet square. Square it off and line it with bricks. Drop in a sump pump and plug in the pump. You're done. Of course you need to have someplace to go with the water it's gonna pump out. (Hint: downslope from your house, or into a drain line)

The sump plan is good to go: I have easy access to an unused drain pipe. I will really be relying on that pump, as all of my garden water is going to be drained through it.

The place really is remarkably clean for what it is. No sign of mold. I really do not believe its condition is a threat to myself, and structurally, everything looks pretty fresh for a 40-50 year old construction.

To me growing weed is a hobby, not a challenge. If your situation was mine, it would no longer be a hobby and it would eventually be a burden in my life.

Interesting you mention that. I'm an engineer.

Meaning I enjoy the build. After everything is set up the way I want it, the only hassle I will need to deal with is the low ceiling and small entry way. My experience in growing is in short cabinets with 400w lights. After dealing with that, this is looking pretty nice.

GrowinSmoke said:

Just because the crawl space is moist doesn't mean the grow room has to be moist. I just need to isolate it. By the time the moisture down there is rising I will be pulling air from my living area.

What's your set up like?

Click to expand...

Im not sure what you mean on this...

your growing in the space that gets up to 6 inches of water from what I read.. Which means the space is moist.. Your going to build a floor over the water line? The water will just sit there and heat up from your lights thus resulting in mold and moisture...

Ok you grow in a tent with the floor still over the water line.. Let's say there's 4 inches of water down there.. Your growing in a tent... Water evaporates which creates humidity.. Your tent has a intake, and a out take.. Most likely your intake is passive and your exhaust is active... That means you WILL pull humid air into your tent.. The sump pump is the only solution... It can't be that hard to dig a little hole to put a trash can down there... Doesn't have to be a huge 30 gallon one anything is better then nothing.. The floor build over the waterline or whatever you were gonna do is a no go...

You aren't reading the whole thing.

fir3dragon said:

Im not sure what you mean on this...

your growing in the space that gets up to 6 inches of water from what I read.. Which means the space is moist.. Your going to build a floor over the water line? Yes The water will just sit there and heat up from your lights thus resulting in mold and moisture... ~1200w of lights contained in a tent and above a floor will not create enough heat to significantly heat up 6" of water covering the entire crawlspace. That takes an enormous amount of energy.

Ok you grow in a tent with the floor still over the water line.. Let's say there's 4 inches of water down there. The sump pump was mentioned in the first 5 posts, and was immediately put into the plan. Your growing in a tent... Water evaporates which creates humidity.. Your tent has a intake, and a out take.. Most likely your intake is passive and your exhaust is active... That means you WILL pull humid air into your tent.. If I am pulling in crawl space air, it will be before I stop running the heater, and before the moisture becomes an issue. Currently the crawl space is under 65* and 50% humidity. I've never been able to get much humidity in veg, so this may be too much, or it might be kind of nice (really not sure yet). As long as the humidity is acceptable with a sump pump, and the temperature stays nice and low, I will entertain the idea of pulling crawl space air through the intake. However, chances are I will be attaching my intake to my home's HVAC system. I believe I will then be able to pull in 70-75* dry air from my living area, and then significantly colder air for a short period when the AC kicks on. The sump pump is the only solution... It can't be that hard to dig a little hole to put a trash can down there... Doesn't have to be a huge 30 gallon one anything is better then nothing.. The floor build over the waterline or whatever you were gonna do is a no go... Absolute dependence on either one method is a no go in my book. I'm not going to come home from a long, rainy weekend just to find a failed sump pump and flooded tents. I am also going to be doing a lot more sitting than standing down there, so I'm sure that platform is going to be much appreciated.

Click to expand...

The temp/humidity of the crawl space is still a concern, but only because I am unsure of what exhausting both tents within the crawl space will result in. This may also be the deciding factor in what I use for an intake source Despite many warnings, in my old place I vented to the attic. Granted, it is a whole different environment, but I never found any mold.

If water is an issue you simply use silicon caulking for every single crack and cranny on the floor, then paint it all with that waterproof blue paint (don't know the name) that way if you get spills it goes nowhere. Basically you just need to 'seal' the floor.

70-75 degree intake air for 1200w of lights isn't enough IMO... But go ahead try it...