My observations on adjusting PH levels with nutes added.

[RandyL]

I've got my first grow going, and things are doing pretty well, I'm at day 29 of vegging today.

During this time, I've noticed things about adjusting Ph levels with and without nutes in the water, and wanted to write it out here and see if everyone else deals with this also, or if I'm doing something wrong.

I use RO water, a Hanna Checker 1 Ph meter, Fox Farms Grow Big and Big Bloom fertilizers currently. And Fox Farms dirt for the plants. And Grow More 30% KOH Ph-up solution.

First, I calibrate the meter with the 7.0 and 4.01 checking solutions. It usually drifts 0.1-0.2 Ph in the course of a week. The plain RO water by itself checks in around 5.8-6.0 Ph most of the time. Sometimes, I set one of the settings by turning an adjuster screw, then set the other one, then come back to double check and end up removing some or all the the screw turns to get the first Ph number back where it needs to be. I think more and more that this meter is a POS the more I use it! Or maybe this is normal?

To get the Ph into the recommended 6.3 to 6.8 range, I shake up the Ph adjusting solution (I also shake up the fertilizer bottles just before using them also), and one or two drops of Ph-up is all that is needed to move a gallon of RO water up about 0.5-0.8 Ph.

Whe I started adding nutes, I did it at 25% strength the first time, 50% the second time, and today was a full 100% charge. According to the published Fox Farms liquid fertilizer list.

When I did it at 25%, I noticed that it took more drops of PH-up to raise the PH to the needed level. Maybe 5-7 drops. When I did it at 50%, it took more drops, maybe 10-15 to raise the Ph enough.

Today when I mixed up the 100% fertilizer, it took 26 drops of PH-up to raise the Ph to around 6.5-6.7.

Also, I've noticed that just by adding the fertilizers to the RO water, that alone drops the Ph somewhat, maybe 0.2-0.3 Ph.

Do other people get these same results when adjusting their nute mixes, or is it just me?

And another thing - the Ph meter itself. I've noticed this also, and I'm not sure if the meter is a piece of junk, or this is just how they work.

When I put the meter an inch or so into plain RO water, it'll take 3-4 minutes to settle down and give a steady number. Typically the Ph reading will start high, drop down low, and come back up to the final answer.

Today, with the 100% nute mix, I'd put the Ph meter in, and within 5-10 seconds it had its final answer ready. It'd move very little, like less than 0.1 Ph.

Then if I rinsed off the meter and put it back in plain RO water, it'd take a few minutes again to stabilize.

Who can tell me their experiences with this?

 

[OldMedUser]

Hi RandyL

With soil grows and nutes it can be a bit more of a PITA to get consistent and accurate readings on the pH. With RO water there isn't anything in there and some pens have a hard time locking down the pH. How do yo store your pen when not in use? I use a beaker of dilute pH 4 buffer sol'n as it cleans the end in an acidic sol'n. I only calibrate at 7 and mine has auto calibration so no screws. My Hanna TDS pen has them but it's been dead on for ten years.

Have you checked the pH of run-off water to get a better idea of what the pH is in the pots themselves? You could be wasting time and effort messing with the pH before watering if the run-off is way different. Adding some dolomite lime to the top inch or so of the soil could help sweeten the soil without adjusting the pH before hand as well. With RO water and the quality nutes you're using there shouldn't be much fussing around to do.

I'm no soil expert by any means but I've read enough stuff about pot in the last thirty years to have absorbed a bit here and there about all aspects of canna culture.

Any soil guys out there that can chime in!?

Maybe you should copy and paste your questions in the soil growing forum. You may get more accurate advice.

Bottom line is, IMHO, you need to go by the run-off to see the whole picture.

Good luck!

 

[Screwnuts33]

Randy,
I am seeing the same. When using FF Grow Big only the PH is dead nuts one. As soon as I switched to flower feeding I use a bunch of PH-up to get it dialed in. I mix and use 5-gallons at a time and it takes about a cup of PH-up to get the 6.2-6.8 range.

 

[lovethestuff]

Hydro here myself! But I use fox farm nutes and ro water. my ro comes out at 40 ppm and 7.3 Ph. after i add nutes my Ph is mid 4's...It takes about
30ml of Ph up to get it at 5.5-5.7. (35 gal in the res.). then it will fluctuate the most within the first 36 hours I let it go to 6.1 - 6.2 I bring it back down to 5.5 - 5.6 and it is good for that week, from there on out all most all the time...
I use Milwaukee combo meter get an accurate reading usually within 15 sec.

 

[Be Irie]

If you are growing in soil you should find out your soil PH as this will allow you to dial in your PH to what you want. Yes, nutes can either drop or raise the PH depending on what you are using. I use earth juice and my grow and bloom drop my water PPH from 7.2 to 4.3-4.6 depending on whatever else i add in.. the peat moss in the bagged soils will break down and cause the soil to become more acidic, a little bit of lime in the soil mix will solve that and stabilize the soil again.. I will only check the soil run off if a plant starts having issues...

 

[RandyL]

When I'm done using the Ph tester, I rinse it off in RO water, then dip the tip in some yellow electrode storage solution, then I put the cap on and turn it off.

Once I left the thing on by accident, and it was on for 4 days in the cupboard. It needed a serious recalibration after that!

I'll be giving the plants a plain RO watering today, I'll collect some run off water and see what it says for Ph. I did that once early in the growing to see what it said, and the FF dirt made the water slightly more acidic.

 

[OldMedUser]

When I'm done using the Ph tester, I rinse it off in RO water, then dip the tip in some yellow electrode storage solution, then I put the cap on and turn it off.

I leave mine standing in the dilute pH4 buffer sol'n unless I'm not going to need it for some time. It dries out but then I just let it sit in pH 7 calibration sol'n for an hour before I use it.

Once I left the thing on by accident, and it was on for 4 days in the cupboard. It needed a serious recalibration after that!

That sucks. Mine turns itself of after 10 mins if it's not used.

I'll be giving the plants a plain RO watering today, I'll collect some run off water and see what it says for Ph. I did that once early in the growing to see what it said, and the FF dirt made the water slightly more acidic.

Great. I'd like to hear about it. It may be that all you have to do is mix your nutes and water your plants with no pre-pHing if the run off is in the right range. It's one of the main mistakes new growers make is being too fussy about minor details. Like trying to get that pH right on the 0.1. Going up and down with pH adjusting fluids until they've got the water chemistry all screwed up and basically poison their plants.

It's like kids. The first one drives you nuts trying to do everything perfect but after you see him chowing down on a kitty nugget from the litter box, you finally say f**k it and stop sterilizing the nipples for his bottle. lol By the time the second one shows up it's a piece of cake.

C'ya l8tr

 

[Hogdady]

Adding some dolomite lime to the top inch or so of the soil could help sweeten the soil without adjusting the pH before hand as well.

I've been using FFOF for about two years now and have found that mixing in 2-3 cups dolomite lime per bag prior to potting helps ph stability. I am getting a consistent .5 to .8 drop in ph when checking runoff which is exactly where I want to be.