Questions about DWC


OK, this is not a dwc question, but who doesn’t like a good night picture??

Or a baby bud porn??


Your plant :wink:


@MattyBear @Myfriendis410 @GreenThunder @dbrn32 @Grandaddy013 @WickedAle @Bogleg @WickedAle @BigDaddyCain

Thank you very much everybody for your wisdom and your input in helping us decide what to do. I know there are better options to try but for right now, we will be doing a 30 gal tote on our next grow.
The inside of my tent is 30" x 30". This is the tote we’ll be using:

I plan on putting 4 air stones in it and possibly a water pump to stir the water if needed.

Can someone tell me what size net pot and what size rock wool cube I’ll need? Maybe exactly what I need to get started.
Also, I’ve seen the mention of hydroguard or something like that. Is that something I need?
How often will I need to do a water change?

Thanks again! :sunglasses:


I use 3” netpots and zip tie them into the lid. Get a sheet of 1” rockwool. I bought a shoebox full of hydroton that will last for 20-50 plants on flea bay.Get the hole saw kit from harbor freight for $10. Will be good for both your net pots and your RDWC piping.


You will DEFINITELY need hydrogaurd or something like it. @WickedAle knows some good stuff. If I was you, I would put your tote on top of something, and install a drain. A reservoir will make things a lot easier also. I had a lot of problems with root rot until I bought a chiller


I just started using the below, but cannot really tell you if it’s helping. It has everything all of the products have it it for every stage. Trichaderma for damping off, Glomus (Myco) of various species roe root extension and bacillus and other organisms for N2 fixing and better nutrition. Plants are healthy, but I did experience a bit of damping off probably because I run my DWC’s to high with nutes. I had robust growth initially but I chopped on my plants hard to cause branching and it seems to have stunted growth. Could also be because the plant is sharing its nutrition with the bacteria in the DWC. More is not necessarily a good thing. Prior I didn’t t use anything and my plants seemed to grow faster. Again that may be because I stunted them by chopping them hard and not the use of microbes in my DWC. More empirical observation is required to make solid conclusions on the effectiveness of this product. But at $20/lb it is a much cheaper all-inclusive bioinnoculant on the market.


I don’t use rock wool (I use rapid rooters), but I will tell you exactly how I would do it, were I starting out and deciding on a 30 gallon tote.

First, I would buy two or maybe three lids for the tote so I could have different configurations/options if I wanted.

My first attempt, I would grow one plant in the tote (assuming we’re still talking a 32x32 space). I would put a 4" or 6" net pot in the center of the lid. I would use a 951gph or similar air pump with a six site manifold and put six air stones in the tote.

Now - here is the biggest issue I had starting out with hydro: It took me a bit to figure out how to transition the germinated seeds to the totes. My solution was to build a simple bubble cloner and use that to get the seedlings into veg, then move them to the totes. Before I did that, once they rooted through the rapid rooter, I would put them in their final home and top feed them until the roots hit the water. Using the bubble cloner just requires less of my attention and time.


Just curious as to why you strap your pot down? :thinking:


Too many broken branches from the pot tipping over in the lid upon nute changes. Wasn’t so bad when the plants were short and squat, but the auto trees I grew last round wer such a PIA. The zip ties were the solution.


I also tied in my net pots like wickedale because I had the weight of the plant push the entire net through into the reservoir


Yep. That too. Lol


@Gardenguy just curious, did you loose that plant or were you able to catch it in time? @WickedAle Thank you both for your input. I’m sure I’ll be in for a lot of surprises. Right now I’m not even sure of all the questions I have. I’m going to make a lid from the top that came with it so I’ll be able to access the reservoir.

For the time being I’ll be able to use the pump that I have to do reservoir changes. Speaking of which, how long can the plant sit without any water??


I didn’t loose the plant it was in a two gallon bucket and with the root mass it only held a gallon of water which it completely drank in 12 hours or less so I was watching it like a hawk .


I use those storage bins too. as a drip catch never a plant pot

They are better for keeping the carpet dry than growing a plant in


What kind timer do you have connected to your pump, or how much and how often (times per day) do you fill the tray? Thanks.


Right now I have basically two timers connected to my water pump.

First, is this one:

I also use that same kind of smart plug for my lights and heater. Using the app for said smart plug, I can create “scenes.” So, I have a “scene” that says:

  1. If the flower lights are on, turn the water pump and the heater off
  2. If the flower lights are off, turn the water pump off and the heater off

Then, plugged into that smart plug, I have one of these:

I configure that to use a recycling timer. On the timer, I have the “on” setting set to 15 minutes on, and the “off” setting set to 1 hour, 45 minutes.

The end result is that I am currently flooding my table for 15 minutes every two hours during lights on only.

I will say that it took me about three weeks to nail down the flood cycle - and in reality my plants kind of grew into the one I am currently using. My last grow I used one gallon pots instead of the 4" net pots to hold the plants and I flooded for 30 minutes every four hours when the lights were on.


I would also like to note that you could schedule the flood cycles pretty much completely with the Sonoff switch and not need the digital timer - but the Sonoff switch only allows something like 20 schedule instructions on a single switch… at one point I was flooding every hour (might have been some panic in there) and I couldn’t configure enough instructions, so I adopted the second timer as a result.

But now since I am flooding six times per day, I would only need 12 instructions, and could simplify my architecture a little bit.


I’m trying to rig up a simply flood and drain for my (seedlings to small veg) then I’m going to drop my 5 inch basket in my 30 gal tote. Just curious how much they needed watering and how often. Thanks a million!


It will depend on the medium and the amount of it. I use hydroton - and when it’s brand new it doesn’t hold much water so requires more frequent flooding. This is only my second ebb and flow grow and only my first one with net pots… so for me it’s trial and error for now.


I’ve thought about putting my basket in a small tote with air stones and letting the water bubble up onto the basket after my seed and roots pops through the rapid rooters. I’m also planning to surround the rapid rooters with hydroton. Any thoughts. Trying to keep my seeding tray small or seedling tote small if that makes sense.