Increase Soil PH

Never adjusted ph of my soil and have never had a ph related issue. Good soils have buffers and will buffer the ph. Testing your run off is not the best way to test your soil ph, get an actual soil meter or do a slurry test. Now if you are running a soil that's lower quality or doesn't have buffers, then ph adjustment may be necessary. Most products made for adjusting the ph of your water won't change the ph of your soil though, not without the proper elements. To raise soil ph, add something with calcium (like limestone/ dolomite lime) to it. To lower soil ph, phosphoric acid will work. Phosphoric acid happens to be used in General Hydroponics ph down so this product will lower both water and soil ph.

A couple of tablespoons of wood ash sprinkled on the soil surface and watered in will raise the pH. Do not put too much, add a couple of spoonfuls, wait a week for the full effect then add more if needed..........once you go too far, you will cause other issues.........so slowly and gently does it.

How do the plants look? If they're looking ok you may not need to change anything. A single runoff reading isn't all that telling. Tracking runoff is more useful to detect trends over time. Lots of factors can affect runoff- how the sample was pulled, the volume of your runoff, even salt buildup on the outside of your pot(especially with fabric pots).

Garden lime can do it, but it adds ... calcium and something else? can't recall but the gauranteed analysis label has all of that info. So, just have to maake sure you don't overload the Ca and whatever else it adds to substrate. That on top of continuing, i assume, to ph-balance anything you put into the soil will be more effective than 1 or the other alone. pH is a log scale from 7 ("zero"). Each whole number away is 10x more h30+ (7) depending on direction. Runoff is not always super accurate as to what exists in the substrate. You've 'rinsed' out some of what was there and hopefully restored a better balance as far as what remains when you fertigate or irrigate. It's likely less acidic than what your runoff says. So, how does the plant look? Any issues? Then the pH is probably fine, because approaching 5.5 and below you encounter availability issues with Ca before other things.

Make sure your watering Ph going in is on target and check your runoff again. I’d be careful how much you tweak this, you’ll find yourself on the other end of the scale.

Have you took run off from fresh and clean plate ? Was it middle of run off ( not first drops ). If both answers are YES, then its not best thing. I would personally keep good wet/dry cycle and load in when needed a bit higher than my belowed 6.3 ph. So i would target 6.5-6.8 range, few wet/dry cycles and all should go back to normal...