Need opinions and advice for my RDWC design.

Hey, all.

I'm a bit of a noob grower, only having 2 very small scale soil grows under my belt, but I'm trying to design a 24 site 2000-4000w recirculating (maybe top fed) deep water culture system. Each site consists of a 5 gallon bucket with an airstone and 6 inch netpot. The buckets are arranged as close as possible in 4 rows of 6 buckets each. Each row ends at a return manifold which runs back to the control bucket/reservoir. The water is then fed back into the system through the feed manifold. I plan on starting from seeds in rockwool and flowering them after 30 days of veg. I'm considering top feeding each site during veg to accelerate growth, then turning it off during flowering to avoid stem rot. Each plant would be topped/mainlined 3 times to produce 8 colas when flowered. I would hope to yield 7-9 oz per plant.

My questions are:
1. Are my buckets too close together for mainlining? Will my plants be too crowded?
2. Is it necessary to turn off top feeding after a certain amount of time to prevent stem rot?
3. Will I need to cut my water lines all to the same length to ensure even feeding like I would for air lines?
4. Is it unrealistic to hope for a ~200oz harvest in 3-4 months with this system under 2-4 1000w HIDs in a 6'x8' tent?



Here is my design pictured below. Any comments, suggestions, warnings, and answers are greatly appreciated.

[KEY]
GREEN=Water Pump
BLACK=Water Lines
MAROON=Airstones
GRAY=Manifolds
BLUE ARROW=Water Feed
RED ARROW=Water Return
NOT PICTURED=Air Pump, Air Lines

Those plants are gonna be packed in there way too tight unless you're just gonna be throwing a bunch of clones straight into flower and growing some spears. I would recommend AT LEAST a foot between buckets to allow the plants room to bush out. Top feeding isn't really necessary for DWC, it's great at the beginning because you don't have to top water each of your grow sites, but as soon as the roots hit the res in your buckets you won't need the top feed anymore. I've ran top feed before and it really doesn't make that much of a difference, if any. As far as your water lines go, I would do it all out and use 2" pvc piping instead of vinyl tubing. This is going to be quite a bit more work for the initial setup but you simply cannot compete with the flow of nutrients that the 2" pipes afford. To be completely honest, I would scale back your ambition a bit and do less buckets. For an 8' tent you can surely jam a ton of plants in there, but you may be better off only running like 8 sites and one control. The real question is do you want to grow fewer large plants that produce large yields or run many smaller plants that produce less yield. To give you an example, I run two plants in a 4x4x7 tent, this might not seem like much but I also Scrog so by the time they've finished they're flowering stretch, the whole tent is pretty much gonna be spoken for. Not to mention if you are thinking about running (4) 1000w bulbs in there you better have some pretty diesel ventilation plans cause that is gonna produce a shit ton of heat. You're gonna need to air cool those reflectors and get that hot air out and away from your grow room completely. And don't forget a carbon scrubber, we want clean fresh air exiting the grow room, not stank! Anyway, just some ideas for ya, any questions let me know, and check out my current grow, Girl Scout Cookies RDWC Scrog Grow to see how I've got things setup.

Thanks for the reply. I notice that in your setup your buckets are less than a foot apart. Do you mean space between buckets or space between the actual stems themselves? Also will my water lines need to be the same length to make sure I have even circulation?

This is a bit of a business venture for me. I'm planning on moving to a medical state to do this legally and I'm going to need to pay rent. I know yields can vary from strain to strain but what could I hope for with 8-12 plants vegged for a month and trained to 8 colas each under 2000w of light in an 8'x6' tent? Or even 20 plants in a 10'x8'?

I have the room mostly designed already. The lights are going to be in air cooled hoods connected to 2 720 CFM inline fans that run to a large-ish carbon scrubber that I'm going to build. I want to slowly automate the room as much as I can as I go along, things like stepper motors to control light height, automatic nute mixing/feeding, automated rez changes etc. I think I'm going to start out by modifying a digital ph/ppm/temp monitor to send readouts to my phone.

First thing your going to have to do is allow more space between bucket if your expecting to grow plants that will yeild 7-9 oz which is very hard to do in a 5 gal bucket unless you have a high yielding strain and your grows goes perfect.

For this specific setup your best bet is to top feed with 1/2 or 1 inch pvc pipe to each bucket, you can run full length pieces down each side and connect them with elbows and it can drain right back into the main res. I would lie the pipe first and mark 3 spots for each bucket, one dead center of the plant, one to the left of the main stem and one to the right of the main stem. This will allow for maximum coverage while not putting to much strain on the pump. If you use to strong of a water pump then the water will flow over all the holes and it wont drip, if you use to small of a pump then water will not circulate over every hole. Your gonna have to do some trial and error to get it just right. The pond pumps at lowes are very low priced and adjustable so that would be a good buy for this setup.

As far as your oxygen goes.......i think if you wanna get anywhere near 7 oz per plant then your gonna need at least two airstones per bucket. They sell 12 inch airstones on amazon for 3 bucks that will make a 5 gal bucket look like a erupting volcano it puts out so much air. More oxygen in the water equals bigger plants so and one air stone per bucket i dont think will cut it

No need at all to turn off your top feed at any point during veg, ive done coutless trials to see which works best, intervals or running the drip feed 24/7 and running it all day every day produces the best results by far. Keep that thing going all through flower as well if u wanna maximize harvest. Also as the water from the drip breaks the surface of the water it creates more oxygen so its a win win situation.

Good luck with the grow and i hope you get what your expecting. Let us know if theres anyting else we can do to help!!!!!

Yea my bad, I meant atleast a foot from stem to stem, 18"-24" is ideal, mine are a little more packed in there but as I'm scroggin them and not letting em go natural I can control where the growth goes. As I mentioned before I think you're going to want some more substantial plumbing for the water return lines. If you use 1/2 to 3/4" inner diameter vinyl tubing to connect all your buckets, and you also have a water pump presumably top feeding each bucket, unless you go with a low GPH pump, I think you're going to have a system backup whereby to much water is sucked from the control and deposited into the buckets but the return lines won't be large enough to handle this flow of water and wil likely overflow. This exact thing happened to me before I upgraded to 2" PVC pipes, now I have all the flow I could ever wish for. The way I see it is you have a couple options to recirculate your solution. As gtran explained, you can top feed the solution using a pump INSIDE the control and the solution will mix SLOWLY throughout the system as it will take time for the solution that falls into the buckets to mix and subsequently flow back to the control. Option two is you run the pump inline outside of the control bucket and connect the pump inlet to a PVC tee and the far end of your circuit. What this will accomplish (providing you use 2" PVC pipes) is an EVEN flow of nutrient solution throughout your system. Another plus that option 2 affords is that it will be WAY easier to setup, running all those top feed water pipes is gonna be a huge pain in the ass and my mantra for hydro, keep it simple, the more parts you have the greater the chance something is going to go wrong.

I agree 100% though with gtran regarding the airstones in your buckets, get as much air in there as possible, I run large 6" air disks which work out pretty well, they're a bit more expensive than a typical bar airstone but they perform well.

Sounds like you've got a good start on things though largegato! I find that some of the most fun I've had with all my experiences growing is the design and setup of a new system. There are so many different ways to go about things it'll make ya head spin, but once you zero in on what is going to suit your needs the best, it's game on. I just wanted to mention quickly regarding your ventilation. You mentioned you were going to build a carbon scrubber? Now I have not built one before (I use a 6 x 16" 400 CFM rated Phresh Filter) but I tend to think that this is something that you might not want to DIY. If you're going to be running that many plants it's gonna be stanky in there and you wanna make 100% sure you're not gonna have any odor leaks. Go with a professional quality filter, you won't be dissapointed. And carbon filters perform better when they are sucked through as opposed to forcing the air out of them, best bet is to mount the scrubber at the ceiling of the tent sucking out the hot air, connect it to the reflectors thus cooling the bulbs, and then get that hot air outta there by conveying it out of the grow area.

Couldn't even begin to guess about yield, it's all gonna depend on how you setup your system and if you can get it dialed in properly. Pick a high yielding quick finishing strain and run yourself a test batch. That'll give you a benchmark as to what you can expect from future harvests. If you're getting into this as a business venture I would seriously consider having both veg and flower rooms. If you were rocking two 8' tents, both with (2) 1000w bulbs, you would be sitting pretty on some serious green. Another very economical option that you may want to consider is flood and drain tables. Relatively cheap to setup, you can pack a ton of plants in one, and very low maintenance, just some food for thought! Good luck!