Raising pH levels in fertilized water

[MateoinLosAngeles]

Hey all!

I have this old bottle of Dyna Gro Orchid Pro 7-8-6

I wanted to finish it so it doesn't go to waste so I mixed one part fertilizer, with two parts Calcium Nitrate, and one part Epsom salts to achieve a 40 ppm N solution. (About 1/16 tsp/gallon of fertilizer, 1/8 tsp/gallon of Ca Nitrate, and 1/16 tsp/gallon of Epsom Salts).

However, before watering the plants I measured the pH of the solution and it was quite low at 4.5

Is there a way to increase the pH without increasing TDS? I don't have pH up at home so any DIY tips would be appreciated!

[Dimples]

I just add roughly 1/6-1/4 tap water to the jug before finishing filling it with RO and adding foliage pro. The pH of the final solution ends up right around 5.5-6.5 every time. I tried using pro-tec + FP + all RO but quickly gave up because the lack of buffering agents in the solution resulted in the pro-tec causing an extreme elevation in pH if I used juuuuust a tiny bit too much. I was dipping a 1/8 teaspoon into the jar and only using what clung to the spoon, no free liquid. I don’t have access to lab equipment for measuring out 1/4 drops at a time, and using the tap water means I don’t need to supplement with additional calcium or magnesium.

[Roberta]

I would be suspicious that the pH meter is giving you an erroneous reading. So before you do anything at all, it might be wise to verify with pH paper. (Not as "precise" but much less subject to error) I don't see anything in your formula that would give such a low pH .

Then, if you have verified that the reading is real, and you're using RO water, mix with tap water half and half. (There's enough calcium bicarbonate in your tap water to buffer quite a bit of acidity) But I don't see where the acid would be coming from.

[Lil Duck]

What is the tds of your fertilizer solution, too low and a ph meter won’t work. Accurate testing of low tds water is done by mixing pure salt into the water as it raises a the tds but not the ph. Personally I see no problem of a watering solution ph of 4.5 the ph of what comes out of the pot is much more important than what comes in.

[Ray]

1) If you are using a pure water supply, a pH that low is perfectly understandable.

2) No, there is no way to add something without raising the TDS.

3) As Lil Duck alluded to, the pH of the applied solution has almost no bearing on the rhizosphere pH, and that's what's important. Read this.

When I first started using RO, I used Dyna-Gro "Grow" fertilizer and freaked out over the low pH, so I actually bought a $econd metering pump to inject potassium silicate (ProteKt) to raise it again.

I later learned that the plant, media, and microbes they carry affect it far more, so stopped worrying about it at all.