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A Canadian Four Plant RDWC System


Active Member
I am going to build a recirculating deep water culture using 4" PVC pipe.
I want to be able to grow four plants in it as in Canada that is the maximum we are allowed.
The plants would be 24" apart. I would be growing in a 5' x 5' grow tent that has a height of 7'.

This is assembled without glue to get an idea how it will look.

The water and nutrients would be pumped in where the red arrow points. It would circulate
around both sides and then out the tube in the middle. I will need to add something to the
end of the drain to control the water level. It would drain into a plastic tote. The total water
in the system would be 5 gallons. Will 5 gallons be enough?

I have 2" mesh pots that would go where the holes are marked.
I am wondering if 2" pots are enough I could go with 3" pots in the 4" PVC.
The plants would be able to grow to a maximum height of 4' although I would prefer they not get that tall.
Any advice would be greatly appreciated!




Photo of the Month: Jan 2019 - Plant of the Month: Feb 2019
I think you're going to run into issues with only 5 gals of capacity for four plants. Not so much in terms of water volume but in lack of space for the root system.

My first thought would be to add Tee's where you want the net pots. You could extend it up a few inches and give a bit more space for the roots. You could install the middle drain at an upward angle to determine water level in the vertical pipes. Or use a pair of 90s to turn it up and over to accomplish the same thing.

5 gallons isn't a lot of water but if you can manage the roots you can grow a fair bit of plants in it.
Here's three unruly clones in a 3.5 gallon bucket. Total water capacity is about 2.25 gallons. They are in rubber collars no net pots with a Dewey mister for aeration. They are under very small lights and need filled up every week at this point.


Active Member
The downstream roots would have about 36" of tube to grow in.
With about an inch and a half to two inches of water in the tube.
Increasing the water capacity is easy just add more.


Member of the Month: May 2009, Oct 2010, Sept 2017
EDIT: Oops, didn't notice the new posts had already discussed my question about pipes filled with root systems.


Active Member
I fitted all the pieces together and glued them today. I tapped and installed the
brass fitting where the nutrients and water will be pumped in.
There will be two more metal clamps go on the other end I still have to make a make a stand for it.
There will be a plastic reservoir underneath it with the pump.
I may wrap it in foil or paint it to keep the light off the roots.
Both my tents are in use so it may be a few weeks before I get to put it to work.

I will post more pictures as it progresses.


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Well-Known Member
Its in the tent and ready to go. The reservoir has 10 gallons of water in it.
I will put the plants in it later today.

For what it’s worth bud, I would switch that clear hose out for a black hose to prevent algae growth.. Your going to have air stones in your tote right?


Active Member
I will see if I can find some black tubing or wrap it in foil.
There are two 4" air stones in the tote.
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