When to PH water.

[ledscrog]

I'm sitting here thinking about how i feed my plants and haven't really seen anything on this subject.

Basically, I ph my water then add my nutrients. I'm wondering if I'd be better off adding my nutrients then PH the water/nute mix. Anyone have any suggestions? If it matters I'm a soil grower.

 

[Tead]

Nutrients will change the PH of the water. ALWAYS adjust PH last.

 

[go4snypr]

yeah, what Tead said.

 

[Stealthboat]

Yeah most nutes are acidic and will lower your ph by 1 or 2, definitely ph once everything else is in

 

[Tead]

I've been using the Dyna-Gro line for a while now. After I juice up my mix, it's usually quite near where it needs to be. My heavy feeding babies actually get a touch of baking soda to raise the PH a touch.

 

[iwltfum]

It's actually better to find out how much pH adjustment you will need with that particular week on the feed schedule and then pH adjust before hand, but no one really does this.

The reason behind it is that every nutrient you put in your water affects the pH in one direction or the other. For the same reason you don't want to add bloom or grow nutrients before the micro (in GH three part), you would want to add the most pH affecting nutrients first (that includes your pH adjustments) with any line of nutes.

The science behind it:
Each change in pH takes either hydroxyls or carboxlys (depending on which direction the pH is swinging) for the reaction. Your nutrients are made up of hydroxyls and carboxyls so every time the pH swings, the water is taking a certain amount of your nutrients to do this and making those nutrients inert (unusable to the plant) by attaching them to other molecules for the sake of homeostasis.
If you put pH adjustments into a bucket full of nutrients that are all ready mixed up, the adjusting solution will be concentrated in a small area of the nutrient solution (at least for a second, even if you stir immediately) causing your water to have a different composition than it had before AND, because it's concentrated, has a great affect on the molecules in that particular area of concentrated solution, hence why you would want to affect the pH before you add nutes. But you can only do this if you make the nutrient solution first and then test how much pH up/down is needed, then make it again with the pH adjustment at the front of the line.

Like I said, no one really takes the time to figure this out for their nutrients and it seems to work just fine the other way around. I always make sure my nutrient solution is moving pretty fast by stirring it vigorously before pHing or using a very lively air stone while mixing nutes in general.

EDIT: I've also heard that with a properly buffered soil, you don't need to pH adjust anything. All that I wrote /\ up there has a little more to do with hydroponic nutrients than organic nutrients, but pH adjustments do work the same way with organic nutrients.

 

[Cannabliss89]

Yea it depends on the nutrients too, like iwitfun said above some nutrients don't require PH adjustment. I haven't adjusted the PH since I started feeding because my nutrient line doesn't require it. I was a little nervous doing this at first, but my girls are healthy and it makes feeding a little easier.