Measuring the pH of a whole garden. Is it worth it ?

Winston_The_Gravity_Man · May 2023

I reckon that advising owners of new gardens to measure the pH of the soil using a meter is a waste of time. I've seen it talked about lots of times in books and on the telly.

The pondus hydrogenii (pH) measures differently everywhere in a garden because of the nature of garden soil, areas that have seen the application of acidic peat, limey areas, and other things.

Surely a pH meter is better used immediately before planting so that the 'perfect' conditions for a plant can be arranged. Or not ?

Liriodendron · May 2023

I think it's useful when planning a garden to have a fair idea of the pH of the soil; there might not be a lot of variation across the area, particularly if it hasn't been cultivated (eg it's a new build). Waiting until you've bought your expensive rhododendrons before discovering that you have very alkaline soil throughout your garden could be... disappointing, to say the least.

Loxley · May 2023

There can be variations across a plot, e.g. generally slightly acid soil but alkaline where an outhouse with lime mortar was demolished, or next to an old brick wall with crumbling mortar. But I wouldn't worry about timing, as such. Measure the existing soil in the area you want to plant.

Winston_The_Gravity_Man · May 2023

Talking of new builds, @Liriodendron, there used to be a trick that builders were infamous for. They'd bury all sorts of rubble and other building detritus in the garden, run a bulldozer over it to flatten it, then sprinkle a thin layer of soil over the top to take some turf. Looked good for potential buyers but they'd soon discover they'd bought into a whole world of (gardening) pain. Wonder if they're still allowed to get away with it ?

Still think I'd prefer to know what additives the soil needed in a specific area before I planted a pH sensitive plant.

Fairygirl · May 2023

Judging by the endless queries on this forum @Winston_The_Gravity_Man - nothing has changed in the building world...
I'd agree with @Loxley - just check the bits you want to plant into if you're concerned.
Many plants aren't fussy as to soil pH anyway.

fidgetbones · May 2023

If you have one of those meters that you just push in the ground it would be useful. I believe at Highgrove, it is mainly neutral to slightly alkaline, except for one broad strip of acidic soil where they grow all the ericaceous plants like rhododendrons and azaleas. There are gardens near me where they grow lovely azaleas. They just die in my soil. What I'm trying to say is it could be different in quite a short distance.

fidgetbones · May 2023

Application of acidic peat to limey soil is a total waste of money, as it has sod all effect.

Fairygirl · May 2023

Indeed @fidgetbones, and the other way round too, when people want to change acidic soil.

Rhodos etc are fine in neutral soil as long as it isn't the alkaline end of neutral. I think there's a couple of exceptions to that, but most people aren't buying from specialist nurseries either.
I also think many people don't quite understand that neutral soil covers quite a wide variation in pH.

bédé · May 2023

I am a chemist; I have a probe-type pH meter. But I rarely use it in my garden as pH can vary enormously over short distances. Builders' deposites has been mentioned; in my case the previous owners spread chalk lumps willy-nilly.

I did use it on my daughter's garden in the chalky Chilterns to find that her Clay-with-Flints soil was surprisingly pH 6.5. Rhododendrons were fine.

Just looking at what is growing well in the locality, and trial and error, is adequate.

I do think it is helpful to get to know your soil in different parts of the garden. I think a sedimentaion test that shows you the ratio of stone : sand : silt : clay : organics is the most important. If your test cheapo evergreen azalea goes chlorotic, treat it with Sequestered Iron. If your blue hydrangea goes pink, accept that, or add some blueing agent.

BTW I have always just accepted that pH is pH. I always believed that the "H" stood for hydrogen ion concentration, and that the "p" is a well-known to mathematicians for the way H+ (in this case) is treated mathematically.

punkdoc · May 2023

Trial and error can be very expensive, and is surely not to be recommended as good gardening practice.

If you want to plant acid loving plants, check the pH in the area you intend to plant them in. Don't just chuck them in and hope for the best.

JennyJ · May 2023

I tested the pH in several places around the garden with the little sample-bottle test kit when I first started gardening (slightly to the acid side of neutral everywhere I tested) but I don't bother now. It won't have changed much if at all. Since then I did some more testing (distilled water and universal indicator strips) for an Open University course that I did, same results. We also did the soil sedimentation test on that course - no surprises, lots of sand and a barely visible layer of clay particles. The standard squeeze/ball/sausage test gives a good enough indication for most gardeners. It was fun though, and needed no specialist equipment, just some straight-sided glass jars (I used ones from pasta sauce), water, a ruler and the soil types chart. I think I've posted pics on here at some point.

Measuring the pH of a whole garden. Is it worth it ?

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