RDWC general info


It’s my first grow and I’m using a 4 bucket RDWC system. I’m trying to find any sites or info on how to properly add nutrients and general care of the system.


Pics of your setup might help. There’s several RDWC people here myself included. Do you have a ph and ppm meters? What nutrients are you using? Do you have hydroguard? Where is your reservoir? Tent or room? I could go on and on. It would be more helpful to ask what you don’t know than for me to try to explain everything.


My equipment I have is the following: ph meter,tds meter,heater, humidifier,r/o water system, 12” oscillating fan and have ordered a water chiller. Chemicals I have are ph up/down, cal mag, bergmans plant food kit- seedling,flowertime,growtime and plant booster. Bergmans mold control, root protector, bug blaster. Resivor is in the tent


It sounds like you’re pretty well setup. The RO water will be a big help. I don’t know the bergmans lineup that well but i’d suggest ordering hydroguard and a calmag and liquid silica supplement. Other than that you’re off to a good start. I wouldn’t add any nutrients until at least 2 weeks but you’ll want to wait until either the cotyledons start dying or the plants show they need food. Starting nutrient will be a little less than half the recommended dose. Each week to ten days or so when you swap the water out you can increase the food by using half the recommended dose for that week on the feeding schedule. I try to do a 100ppm increase each week rather than using recommended dose. I’m sure others have similar methods.


I really appreciate all the time and help it’s hard to find good info out there on this. When u say wait 2 weeks is that once I put the seedlings in the rockwool cube into the dwc bucket then 2 weeks?


Yes after they’re in the system. You’ll also need to top water them until they get their roots into the water. I used someone heres suggestion of 1 cup of water per day watered around the media not on the rockwool. And make sure your water level is at least 1.5 inches below the net pot. Otherwise the plants will die if they stay wet at the stem line.


I’m glad u said that the directions show the water level above the bottom of the net pot and that didn’t seem right. My system has a self top feeder built into it. Should I not use that at the start?


I looked into a top feed. If you use it make sure it’s not soaking the cube. And you need to turn it off once the roots hit water. Lots of lost plants due to top feed systems. But if used correctly it’ll be fine. I would ask @peachfuzz or @bryan if they’ve used one for more info. They both have way more experience than me. So I’m sure they can offer more help. And they’ll probably see something I missed. It’s a lot of info and some of it comes from doing it more than reading it.


Its agreed… ditch the top feed once roots hit the water… it will only aid in killing your plants… :wink:



Great thanks! Now while I have the top feed on do I have it run non stop? But how then will the nutrients get from the resivor bucket into the 4 grow buckets?


Don’t use it as a top feed, just let the water fall into the water not on the hydroton


No … you want it on a timer… run it for 30 minutes every 4 hours … and just like @boardsbird said … dont run the water over the rockwhool…
Also you just said how does the water get back to the res…:thinking:… there should be return lines to take everything back to the res… :wink:
Do you have a link to your setup so we can see what your working with…?


Yes it does have the return line I was just confused about when to run the pump. Here is the link to the system I have



Once my seeds germinate, I put them in rockwool in a humidity dome, under a 125w cfl bulb that’s on for 24hr a day. They stay there for 7 days, at which time I will put them in my system at 1/4 strength nutrients. Running my water level approximately 1 1/2inch below the net pot. I have 4 2x4 air stones in each container, and have enough water bubbling up to keep rockwool damp. If not, you can pour a little in.


Here are some pics of my plants just starting out about one week. Just wondering how they look and the one pic is a smaller plant than the rest and is yellowing around the edges. All 5 cubes were soaked in ro water seeds put in after 6 days I took each cube and dunked about half way down the cube until I saw moisture at the top of the rockwool and pulled the cube out about 5 seconds in water. Have done the same to all 5 cubes same water just wondering why this is the only one looking like this


That one that’s crispy looks burnt. Are they in a humidity dome? And how close is the light? No nutrients correct?


Yes in a dome I believe they are 33” from light. Light is a 1200w king plus led. No nutrients just ro water. That one came out small, looking kinda like that from the start


Hmm yeah sounds like you got everything covered. Your cubes might be to wet. I squeeze about half or more out of mine. Then I use a small plastic box with clear lid to keep the humidity really high for a week then transfer to a bigger box and dome.


I’ve only watered them once in the past 10 days and I just took the cube put it halfway down the cube in ro water for about 5 seconds until I saw moisture appearing at the top of the rockwool


Oh yeah that’s way too much. I spray water into my dome and if the cubes feel too dry I’ll spritz them with a small spray. They’re probably way too wet. Those cubes soak up water so fast if you even touched them to a puddle of water they could be to wet. Give them a gentle squeeze. If water comes out they’re too wet.