Plants Depend On Having The Right Soil Conditions If They Are To Thrive. So Gardeners Need Simple Soil Tests To Determine Soil Type, Structure, Compaction & pH. Here Are My 4 Simple Soil Tests

There are many types of soil. Clay, silt and sand are the most commonly recognised. But how can we be sure what we have? And is the soil structure good and what about the soil pH? DIY soil testing can help .

Simple Soil Tests

We can do some very simple tests that don’t need any special equipment. Of course, we can take soil samples and have them professionally analysed in a lab, but that is costly and simple DIY soil testing is the starting point I recommend.

What Does a Soil Test Show?

Everything from the pH, soil constituents and nutrient levels are possible in the laboratory. From these we know what will grow well in our soil, what fertilisers are needed and even some indication of irrigation needs.

And we can get good indications of these factors from the simple DIY soil testing tests I show here … at close on nil cost.

How To Take Soil Samples

If you take just one soil sample out of your garden it might just coincide with when someone has stored compost, sand or had a bonfire and give you skewed results.

So it’s best if you take a number of samples and mix them together in a bucket. Then take a sample from the bucket. That way you’ll have a representative sample.

To sample evenly across the plot take a W shaped path across the plot and sample from each arm of the walk.  Take about 20 samples in total.

Soil Testing: The Jam Jar Test

Soil Testing: The Jam Jar Test
Soil Testing: The Jam Jar Test

This is a test that will give you an idea of the relative amounts of sand, silt and clay.

Take a large wide-necked glass jar with a screw lid.  Half fill with the soil sample.

Fill the jar with water, add a little detergent and shake to break up any soil lumps.

Stand the jar in a well light area and watch as the sand fall to the bottom of the jar.

The sand, being heaviest, soon deposits, then slowly over the next 24 hours the silt and finally the clay form layers. The organic matter is likely to float on top.  Some of the clay will be so fine that it will stay in suspension in the water.

A good loam is going to be a mix of clay. silt and sand and will be classified accordingly as, for example, a clay loam, a sandy loam, a silty loam, a sandy clay loam, .. there are lots of options. All of these are good soils but their characteristics will be determined by the preponderance of the soil types within them.

If you look at this glass jar of soil you can see it is largely made up of

  • sand in section 1
  • a lesser amount of silt in section 2
  • and a small amount of clay in section 3.

This makes it a sandy loam.

DIY Soil Testing: The Soil Squeeze Test

All these tests are indicative of the soil you have they don’t replace laboratory testing but do serve as a good indicator that is quite good enough in garden situations.

Soil can be very sandy, very clay or something in between. The in-between will be some form of loam which we know ranges through various types as indicated in the Jam Jar test.

This test is even quicker than the jam jar test.

Take a handful of moist soil. Squeeze it in your hand.  Now open your hand. If the soil crumbles it is very sandy. If it retains its shape it is clay and of course, something in between is going to be some sort of loam.

The Soil Squeeze test takes just a few seconds. It’s crude but indciative.

DIY Soil Testing: The Finger Smear Test

Take some moist soil and rub it between your fingers. If it feels smooth and silky it is probably pure clay. If it is very gritty and coarse it is pure sand.

In between sand and clay are the loams and those that frequently test soil like this are very good at estimating the soil type as well as any laboratory test.  Think of them like the people that can take a swig of wine and tell you the country of origin, grape type and year of picking. It’s not magic, it’s experience and practice.

Soil Testing For pH

This test gives an approximate pH of your soil.

Take two spoonfuls of soil and put one in each of two containers.

To the first add enough vinegar to cover the soil  If it fizzes or bubbles the soil is alkaline.

To the second add some distilled water until you have a thin slurry. Now add a couple of spoonfuls of baking powder. If it fizzes the sample is acid.

If neither sample reacts you have neutral soil.

More on Garden Soils

What is Soil? 

Soil Types

Mulches & Mulching

DIY Soil Testing


2 thoughts on “DIY Soil Testing For Soil Type, Structure, Compaction & pH

  1. Donna says:

    Thanks for this helpful guide. One note: for the pH test, US readers should add baking soda, not baking powder. Baking powder has both acid and base and will fizz and bubble on its own, no acid needed.

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