Soil testing at home - and what do we learn?

We often hear the phrase "sandy or clay soil", but what does it mean? We'll help you learn more about the structure of your soil. Soil testing at home isn't as hard as you might think. A simple jug test can tell you how sandy, silty or clayey your soil is.

Soil testing at home step-by-step

1. Fill a one litre glass container half full with soil and then top up with water (up to 90%).
2. You should also add a few drops of liquid soap.
3. Then, if you shake it for at least three minutes and leave it to settle for a day, it will show its structure.

Take the soil sample from your garden from the root zone (about a spade mark), but push away the top part (leaves, stones, etc.). Test only the soil! 

What will we find during the soil test?

The wet part on top will separate from the solid parts below. The organic matter will separate out on top of the water. The sand fraction will be at the bottom of the solid particles. Above this will be the sludge part and then the matter particles on top.

• If sand particles dominate, our soil has a light, sandy texture. 
• If the proportions of the three fractions are similar, then we have silty soil.
• However, if the material part is the most (above 50%), you have clay soil.

This can also be accurately determined in the laboratory during soil testing.

Lessons from the soil test: what does it mean if a soil is sandy or clayey?

Sand particles are nearly 100 times larger than tiny clay particles. The surface area of the small clay particles is thus 1,000 times larger than that of the "huge" sand particles.

Clay colloids, the buns of the soil 🙂

These tiny colloids of clay, a few microns thick, build up like sheets of breadcrumbs.

In the middle are layers of central silicon (Si 3+) molecules. These are surrounded by oxygen (O) molecules as the next layers. Outside are the hydrogen (H) molecules. The central silicon (Si 3+) molecules can be exchanged, for example, for iron (Fe 3+) and then have a reddish colour, or for aluminium (Al 3+). 

Clay colloids with a negative surface attract positive nutrients!

Hydrogen (H+) molecules on the surface of these clay colloids have a positive charge. In the soil, they can be replaced by other positively charged molecules such as calcium (Ca2+), magnesium (Mg2+), sodium (N+), potassium (K+) or ammonium (NH4+). It is best to have a soil with a cation content of mostly calcium, as this is ideal for soil structure.

The mysteries of soil testing: what about sandy soils?

If your soil is sandy, it is dominated by large sand particles. Their surface area is 1,000 times smaller than that of tiny clay colloids. This explains why sandy soils have a low nutrient retention capacity!

Is clay soil better? No, because if a soil is very clayey, the tiny clay particles will clog the soil and it will become airless and difficult to cultivate!

Can we change the sand-to-clay ratio of our soil?

Not really. What we can change is the organic matter, humus content! Fortunately for us, the humus particles have not only a negative but also a positive charge! So they can bind negatively charged sulphate (SO42-) and nitrate (NO3-) nutrients! So if you increase the humus content of your soil, it can fix more nitrogen and sulphur! We recently wrote about the the importance of soil improvement instead of soil replacement techniques, this topic is also relevant to this article, because in order to help our soil, the first step is to get to know it. Our environment is smart and has already found the most natural solutions, we just have to listen to it.

The ultimate hummus weapon!

Blackjak