How do you test your soil, and does pH actually matter?
With a simple kit or a laboratory test — and pH matters enormously, not because plants care about acidity directly, but because it controls which nutrients are available to be taken up at all.
Why pH governs nutrition. Nutrients change chemical form with acidity. In alkaline soil, iron and manganese become locked up and unavailable, which is why acid-loving plants develop yellow leaves with green veins on chalky ground — the iron is present and unreachable. In very acid soil, phosphorus becomes unavailable and aluminium can reach toxic levels. Most nutrients are most available between about pH 6 and 7, which is why that range suits most plants.
How to test:
A home kit using a chemical indicator — cheap, adequate for the broad picture.
A meter, convenient and frequently unreliable unless well made and properly calibrated.
A laboratory test, which reports pH plus nutrient levels, organic matter and texture. Far more useful, and worth doing once for a new garden.
How to sample properly, which matters more than the kit: take several samples from different parts of the plot, from the root zone rather than the surface, avoid areas near paths, walls and compost heaps, and mix them. A single sample from one spot tells you about that spot only.
What the result should change:
Plant selection first. Working with your soil is far easier than fighting it, and this is the most useful conclusion.
Lime to raise pH, slowly and never with fresh manure.
Lowering pH is genuinely hard and largely temporary — sulphur works slowly, and the common advice about vinegar or coffee grounds does essentially nothing. For acid lovers on alkaline soil, use containers with ericaceous compost rather than trying to change the ground.
Organic matter buffers everything, moderating pH extremes and improving structure regardless of type.
Texture matters as much as pH — the jar test, where soil settles into sand, silt and clay layers, tells you about drainage and how to improve it.