Controlling pH of trees

What is your preferred method of adjusting pH of a tree’s root system?
Lemon juice, cottonseed, etc? Additionally, where do you take your sample for pH testing?

My favourite and only method I have used is the choice of substrate for the particular species!
Caveats; My water supply is close to neutral and I use balanced low power fertilizer whether organic pellets or liquid slolutions!
This may not be possible in all situations given that water supplies vary so much and soil mix choices can be limited for some budgets and availability.

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I’ve been using vinegar to lower the pH, but the preferred method is to use organic fertilizer on the soil surface to you don’t have to adjust the water. Citric acid could be another good candidate for acidifying the water if you go that route.

As for testing, I check the water coming out of the hose as that’s what the trees get.

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Been using vinegar for years with good results. Tap water here is pH 8-9, in a 200litre tank I condition the water down to 6 with vinegar and allow to de-chlorinate

Does anyone have experience acidifying water with left over coffee? My dad had a buddy who used to swear by this. Long ago and long gone unfortunately so I don’t have as a resource. Is de-chlorinating your water a thing that is worth the effort? Thank you.

I’ve always been interested in acidifying my water for healthy and finicky plants (azameas, j maples, etc.); but I have never done it because I thought most methods were too complex (siphon hose/tank systems, collecting rain water, using huge tanks/vessels, etc.).

But, the vinegar method sounds very easy and doable for me! (I’ll just use my 2Gal watering can)

I have a few questions…

  • Minimally, how often, and when(which seasons?), should I water/treat my plants with the vinegar-solution?
    Daily, once every other day, once every couple of days, once a week, once a month, once a season?
    Trying to do the bare minimum required… because I have tons of pots and can be lazy/procrastinate from time to time, haha.

  • I use regular deep nursery pots (1 gal, 5 gal, 15 gal sized pots). How much of my 2Gal watering-can (filled with the vinegar solution) should I use per pot?

  • Should I use the vinegar-solution after I first thoroughly water the pot with regular hose water? Or, should I just water the pot (come watering time) with only the vinegar-solution?

Any help greatly appreciated!

This is an interesting article/testing/experiment (citric acid vs. vinegar):

Excellent. No moss growing on u.

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Regarding the pH issue, it is important, as many nutrients do not absorb at abnormal pH’s. Also, the basic issue of plant health is at risk. When to treat your water supply is similar to asking how often should we take in oxygen. The degree of adjustment is important as well. Rapid, drastic swings in pH are deleterious as are the end points. Each water supply is going to be different. The change in pH that is necessary is small. Plants like pH from 6.5-7.5, in general. If you specialize in azaleas, camellias, or other acid loving plants, then you will adjust accordingly. The very first thing for general trees that should be done is to check the pH of your water supply. Usually, this is a city water supply that is treated to avoid transmission of harmful bugs. I use a moisture meter that checks pH, moisture, and lumens of light received. I tend to aim for the slightly acid pH goal of 6.5-7.0 because most water sources tend to be alkaline. Every time you water, you should treat for pH. Water with the adjusted pH thoroughly every time you water. I use the white vinegar method. I put one tablespoon per 2 1/2 gallon water can. Another thing that might be helpful is an open top watering can. After I water, I immediately refill the water in my cans to sit over the next 24 hours, hopefully enabling dechlorination by evaporation to occur. This is the object of water barrels on a smaller scale. My final point is to proceed slowly in changing the pH. This will hopefully avoid acid poisoning of my trees. I hope that this will help without seeming verbose.


Robert said it - the answer to how best to proceed depends on the current pH. The pH of municipal water commonly changes throughout the year which means the approach to acidification would also change.

As for when to do it, I’d try to be consistent as trees don’t like variable pH from day to day. Better to limit the pH changes as much as possible with your approach to acidification.