DWC & Root Mass - Nute and PH amounts should change!

A huge overlooked issue lots of DWC growers over look is root mass and the effect it has on volume in the reservoir. By the time your 2 weeks into flower your roots are taking 1/4 to 3/4 a gallon of liquid volume and if you don't take the loss of water into account it will throw your nute levels off from what was intended. By the end of flower you can loose 30% of your actual water to root mass volume.

Here is a simple example:

Lets say we have 2 plants in a 13 gallon tote that is filled with 7 gallons of water, by the time we get into flowering we lost .5 gallons of water to root volume per plant but for this example we aren't taking that into consideration. Every time we mix nutes for a reservoir change we are using 7 gallons of water to determine nutes but in reality we only have 6 gallons so we are off every time. This can cause big problems like burn or for us to scratch our head when we use the TDS meter.

I just wanted to point this out because it is one of THE MOST OVERLOOKED common mistake that a DWC grower makes without ever knowing it and it is almost never talked about. This explains so many weird problems so many have and if estimated accurately allows a DWC grower to be at what levels were they want to be with perfect accuracy. It is almost impossible to have deficiency of any sort (if PH levels are correct) when growing DWC and root mass is the cause most of the time in miss diagnosed various other problems.

I just wanted to share for the growers out there that are overlooking the issue and it has more impact on the growers who are using the smaller systems.

Thats why they make meters. Mix it, test it, adjust it, use it.

superstoner1 said:

Thats why they make meters. Mix it, test it, adjust it, use it.

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Thats not always the practical approach and yeah that would solve the problem but be extremely time intensive and laborious. If I was working with 10 gallons and having to premix and test everything that would be a chore and a half. simply putting a line in your rez that represents your desired gallons and just working with that single number is much less labor and time.

Yes your way is politically correct but it's not always an easy possibility depending on how much water your dealing with, distance from water to rez, jugs your capable of moving around etc... If I had to pre mix and test everything before hand rather then just mixing my nutes into a 1 gallon jug at the end I wouldn't even bother with it.

Anyhow, this reminder to calculate root mass in your measurements is for the growers who always think there dealing with a fixed amount of liquid and add most of there chems at the end, and I believe that to be a large percentage. I will concede that your process is fool proof and practically impossible to mess up on but in exchange for time in labor.

just dont see how u can say my way is time intensive and laborious. Whether it is my 5gal res or my 50gal res i always add water to the same level then add nutes and adjust ph, and the 50gal only takes about 12-15min to empty, rinse, fill, add nutes and adjust. The 5gal maybe takes 3 or 4 mins, a very simple process. Im not arguing with u just a big believer in K.I.S.S. and although u beseech more work it sounds like u are making much more work for youself.
I have never let rootball size even be a consideration for changes in res. My 5gal plants are vegged 3-5 weeks and are very nice sized plants and every single 5gal bucket gets filled to the same 5gal line whether it is just going to flower or been in flower for 8 weeks. It really sounds like u might he over thinking things.

Has anyone tried parting or spreading root balls throughout growth?

superstoner1 said:

just dont see how u can say my way is time intensive and laborious. Whether it is my 5gal res or my 50gal res i always add water to the same level then add nutes and adjust ph, and the 50gal only takes about 12-15min to empty, rinse, fill, add nutes and adjust. The 5gal maybe takes 3 or 4 mins, a very simple process. Im not arguing with u just a big believer in K.I.S.S. and although u beseech more work it sounds like u are making much more work for youself.
I have never let rootball size even be a consideration for changes in res. My 5gal plants are vegged 3-5 weeks and are very nice sized plants and every single 5gal bucket gets filled to the same 5gal line whether it is just going to flower or been in flower for 8 weeks. It really sounds like u might he over thinking things.

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There is no extra work what so ever if you simply assume you lost .5 gallons of water per plant when you hit 1 week of flowering. That's the uber quick correctional method. Every single time I harvest I do a root mass test just out of curiosity so I have a graph of whats going on so I could round things off and be simple about it.

I have a square 5 gallon container that has .25 gallon marks all the way up, after harvest I submerge the roots and fill till 5 gallons the shake and remove roots, on average there is only 4.25 of water which concludes that .75 gallon was lost to root mass.

Knowing how much water I'm actually dealing with allows me to add nutes and PH just 1 time with never needing to adjust. Always accurate and where it needs to be. Sorry if I made it sound more complex then it needs to be but you do indeed loose water to the mass of the roots and most don't even consider that is even happening. Not having to adjust without any extra work is efficient.

Superstealthaus said:

Has anyone tried parting or spreading root balls throughout growth?

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I have just because I had to separate plants (taking one out) I wouldn't think you would get any benefit to doing so but possibly if you jabed a airstone directly into the root ball.

im sorry but i dont follow your reasoning here, lets say i have 1 plant in a 5 gallon bucket, and from start to finish i always fill it to the 4 gallon mark, mix in my nutes and adjust ppm/ph. I take my plant out to mix nutes and put new water in, so that 4 gallons is always consistent. So even if the roots get bigger and take up more volume, they are just making that water level rise, but there is still 4 gallons in there. Maybe im missing something but i dont follow.

plantz said:

im sorry but i dont follow your reasoning here, lets say i have 1 plant in a 5 gallon bucket, and from start to finish i always fill it to the 4 gallon mark, mix in my nutes and adjust ppm/ph. I take my plant out to mix nutes and put new water in, so that 4 gallons is always consistent. So even if the roots get bigger and take up more volume, they are just making that water level rise, but there is still 4 gallons in there. Maybe im missing something but i dont follow.

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Then in your case it wouldn't effect anything at all, this is only an issue for those who have systems in which the roots never leave the rez during draining and refilling, which is a large percentage. Mainly totes but plenty of bucket systems can be drained and refilled withing moving the plant.