DWC Seedling Nutes Question

This is a question that can’t be answered with just one answer for every strain.

I’ve had plants that didn’t need fertilizer till the fourth node and I’ve had plants that needed a small concentration of fertilizer right from the get go.

Watch you plant. In DWC if you are using reverse osmosis water on Your seedling, you might find the growth to be stunted fairly quickly, if so mix up a fertilizer solution of about 100 ppm. I’ve had good luck using dechlorinated tap water on seedlings because there is usually enough in there to get them through seedling too veg where I will start incorporating RO water.

Maybe if your going to work everyday and leave the plant unattended but if your at home with the plant them just keep the hydroton wet and it will keep the Rockwool wet.

Air rise top feeds help too keep the hydroton wet while your at work

General Hydroponics 706335 Farm kit, Brown/A


It’s because your plant is drinking more water than is eating fertilizer.

It’s your job to find the 1/1 ratio.

If the ppm concentration was at a lower number when you came back to check then it’s eating more than its drinking.

You either need to drop from 200 to 100 or so or use daily tops offs of zero to low ppm water to keep your ppms stable

You will find that pH will sway the same way when your not at a 1/1 ratio


What I mean by a 1/1 ratio is where everyday you come to check the water level, you find your ppms are at least close to the number they were the day before.

This is important to avoid creating toxic levels in your reservoir and hurting your plant.

Parts per million (ppm) is a measurement of how concentratrated a liquid or an environment is with something else.

If it’s not the same everyday and is constantly rising then it’s possible that if your bucket ever gets really low on water, your ppm numbers could go well above 1500 - 1600 later in the grow when your adding more fertilizer anyway to take care of a hungry plant.

You’ll see many feeding regimes advise mixing up nutrient solutions with concentrations of 1600ppm and putting that into your DWC bucket.
I would never go that strong.

If that plant decides to drink more than it’s eating then it’s fertilizer concentrations will reach semi toxic levels inn only a few hours and very toxic levels after a day or so


Ok when you are on dwc your ppm will creep up due to plant is drinking water and not eating the nuits you will notice the ppm and the ph will drop and rise if the ppm are going up and the ph is dropping the plant isn’t eating as much of the nuits so back them off by 30% if the ppm is dropping and the ph is climbing then they are eating the nuits and you would up the nuits by 10% that’s the easiest way to explain what you are seeing it is a bit more to it but to get you on task that’s what u will see. I cap out at highest points in veg I cap at 750-850 in highest point in flower I cap at 950 never a step higher then 950 ppm. And I’m rdwc


You got some top shelf advice: @TDubWilly is my go to with hydro questions. If you follow this advice you will grow some dank weed.


Yep you got good info above. Watching your PPMs closely in hydro tells the story of what’s going on with the plant. That’s why not just checking it but keeping notes as you go will help you make decisions like when to go higher in nutrients or when to add a little water to bring the number down. I like to keep simple notes at least every other day of PPMs, ph, and any changes I made.


One thing I noticed is when I was in 5 gal buckets my ppm and ph swings where pretty bad and the reason for that was the roots took up more volume in the bucket then the water so a 5 gal bucket turns into 2.5 gal of water and you have to tailor the nuits to that I went to 10gal trash cans and my ppm and ph swings are almost non existent they start to swing when it water change time. But I use 2 cans to grow in and 1 can is my Rez so it works better with a higher volume of water to work with that is something you will notice when you either go bigger bucket or go to a rdwc


RDWC is the way to go if you can accommodate it. Otherwise you can veg your plants for less time but I was able to grow some decent sized plants in a 5 gallon DWC set up.


Thank you all for the feedback! I got this :slight_smile: