pH Nutrient Uptake Chart Confusion

Hi Guys,

I've just fitted a dosing controller so want to dial my pH in. Now I know pH drift is good, however, I need to automate my whole setup to avoid trips each day (from next week I can only visit once a week) - so need to set a specific pH.

I know this is discussed on every forum every single day, however, it's a bit confusing as different charts show different values for nutrient uptake, so I'm not sure which ones to follow.

I've been growing at pH 5.8 in hydrotron, however, I've been studying nutrient uptake charts and from these ones, it looks like 5.3 is perfect.




However, these two charts show that 5.8 is better.



Which ones do I follow?

Thanks,
J.

If you have to pick a value to lock in - aim for 5.8... If you can allow a drift ( not sure what the limitations of your equipment are), dose til 5.5 and let it drift to 6.0, repeat

Why 5.8? Because it's in the middle of the range?

I believe it is fairly common to target 5.8, or 5.5 to 5.8 often considered perfect, and 5.3-6.0 considered very acceptable as well. Realistically you won't have any problems if you can control between 5.3 to 6.0 (or even slightly over). Google "pH hydroponics 5.8", plenty of info from seedbanks and online resources that recommend this pH. I drift from 5.6 to 6.2, zero issues with the drift.

Thanks for the input. I've spent days googling, Hydro pH 5.3, 5.5, 5.8, etc... lol. I guess you could go crazy trying to find a perfect pH. The same with nutrient temperature.

The pH controller I have is also controlled by computer software I'm running on a laptop in growroom, it's pretty good. I guess if I had the time I could write some software to control it to allow some drift.

The big question is would it really effect the end yield?

Anyway, I've locked the pH in at 5.8 and nutrient temp at 66F and will stay with that for all grows.

5.8 and 66F will not let you down. A good thing about controlling pH and reservoir temps is it streamlines plant trouble shooting when you know those two variables are fixed (say, if you are trying to dial in nutrient levels or ratios throughout flower for a strain that is new to you). Reading plant deficiencies becomes easier when you are not having to given much thought to pH lockout or root rot.

As for the Big Question: Controlling pH in the manner you describe will not necessarily INCREASE yield beyond what is typical for your strain, rather that is prevents things from decreasing the yield.... and removing two things from the list of things that can negatively affect yield is always a good thing.

Food for thought on having an advanced controlling equipment....we are basically using chemistry equipment to control environments that are subject to a lot of variables that can influence the pH, and a few of them are part of a bigger problem. If possible - try to pay attention to how frequently your system is having to adjust the pH, or keep an eye on your pH solution levels. Certain microorganism blooms can cause drops in pH, not seeing that the pH is falling may take away a visual indicator of the problem.

Good luck - sounds like you have a nice system set up

Thanks for the feedback again.

Yeah, the main reason I got the chiller was root-rot concern. I'm growing in an extremely hot area of the World. With the aircon in on in my room, it manages about 77 with 50% RH. I wanted to keep the nutrient temp much cooler, I also read a cooler solution also holds more oxygen, so that's a bonus as well.

The system ran perfect last night. The system logs any changes to the PC. I can see in 24 hours it adjusted the dose twice, running the pump for 5s each time, so adding about 10 drops of pH down in total.

I had to visit this morning to check the EC, which is locked in at 1.1 and doesn't move. However, I still want to keep an eye on it. I'm just waiting for my bluelab guardian monitor to arrive, so I can remotely monitor the EC, pH and Temp from that. It means I won't need to visit the room each day to check the EC, maybe once a week which is perfect. It's painful staring at the buds each day wishing they'd grow faster.. he he... I'm sure I'll notice more of a change on a week to week basis.

My idea for the whole setup is to automate it as much as possible, so I can spend as little time as possible maintaining it. I have other work and things to do, so less trips and time in the grow room is better for me.

I'm also monitoring via a camera system as well, just in case. The bluelab guardian will go next to the ph doser.



I did make a few school boy errors with this first grow. The main one was nearly nuking the plants by giving them a too strong solution. The second one was not regularly checking the calibration of my pen ph meter. It was reading 0.4 higher than what it should be, so for a month or so they had a pH that was well out of whack.

You live and learn, I can't wait to do my next grow!