Testing your soil

Testing Your Soil

Testing your soil is a great way to get to know it and understand exactly how healthy it is. We became obsessed with learning about soil around 20 years ago, and since then we've looked into many different ways of testing it.

From detailed scientific analysis, to simple home tests, knowing what's in your soil will help you to understand how the complex web of life works, and what you can do to improve it.

Ways to Test Your Soil

1. Earthworm Test

For beginners, one of the simplest tests is to dig a hole in your garden and count the number of earthworms present within a defined area. Worms act as natural aerators of your soil, creating air pockets within it, so a higher total number of worms means a healthier soil.

• Dig a 20cm x 20cm x 20cm hole in your garden soil.
• Look through the soil that you have removed and count the number of adult and juvenile earthworms that you find. The easiest way to do this is to put them into a container.
• Perform the test in early spring or autumn when the ground is wet. If the soil is too dry, you will not get a good indication of your earthworm population.
• After you have counted the worms, return them to the hole and re-fill.
• To get an indicator of the average population in your garden, dig 10 separate holes across the space.
• High numbers of worms means that your soil is healthy; a low total means there is room for improvement.

Why not try?

The Soilmentor app is a great resource, used by regenerative farmers to test their soil. You can learn more about it on their website here.

2. Water Drainage Test

Another easy way to test your soil is to look at drainage. The healthier the soil is, the more it will act like a sponge, absorbing water and holding on to it, resulting in less erosion and less flooding.

Ideally you want it to take a few minutes - if it takes 30 minutes, you have a problem.

Clay soil - takes longer for the water to disappear. Sandy soil - the water should drain away quickly.

• Dig a 20cm x 20cm x 20cm hole.
• Pour a bucket of water into the hole and time how long it takes to drain away.
• If the water has drained out of the hole within a couple of minutes, then your soil is in good condition.
• If it's still sitting there after 30 minutes, you have a serious problem with drainage and compaction and will need to incorporate a lot of organic matter into your soil

3. Texture Test

To understand the soil in your garden, it's important to know what soil type you have. Your soil type is dependent on local geology and cannot be changed.

For instance, if you have clay soil, you will always have clay soil. However, you can improve the texture of your soil - such as making a heavy clay soil easier to work with, or a sandy soil less free draining - by regularly adding organic matter to the surface of your soil.

The easiest way to discover the texture of your soil is to hold it in your hands.

• What is the texture like?
• Is it sandy and loose or thick and clay-like?
• Does it clump together or does it fall apart?
• Ideally, you want a friable loam - that's a crumbly, dark-brown soil with a loose texture.

Why not try?

• Monitor the plants that are growing in your soil. If the leaves are limp and yellowing and there's evidence of pests, this is a key indicator that your soil health could be improved.

4. Slake Test

A slake test is a simple test that can help you evaluate your soil structure and determine whether you have good levels of humus in your soil.

To perform a slake test:

• dig up a clod of soil and put it in a glass of water
• leave it to sit for five minutes
• after five minutes, evaluate it.

If the clod remains stuck together, then your soil is in good shape and the microlife present is helping it to retain its structure. If you have poor soil, then the clod will have crumbled and the water will have turned cloudy

What is humus?

Humus is the dark organic matter that's created when organic materials decay. Humification brings soil particles together into clumps in a process called aggregation. This process generates an almost glue-like substance which you will be able to feel when you rub the soil between your fingers.

5. The Seedling Root Test

• To perform this test, dig up a recently planted seedling and see whether soil is sticking to its roots. Soil particles which stick to plant roots are known as a rhizosheath. This helps to make plant roots brown instead of white.
• These soil particles help to form a symbiotic relationship to develop between the plant roots and the microbes in the soil and are a sign of good plant health.

Other Ways to Learn About Your Soil

6. Brix Test

The Brix test helps you understand the sugar levels within your plant. Sugar levels offer an important indication of the nutrient levels within your plants, and while each plant has a slightly different range, you ideally want to have a reading of over 12 degrees Brix. This indicates that your plant has a higher mineral content and will be better for your health.

• You will need a refractometer to test the sugar levels in your plant.
• Fold the leaf you want to test into a garlic press.
• Squeeze the press to extract the juice of the plant and drip onto your refractometer.
• Look through the refractometer to take your reading.

As the weather can affect your reading, try to take readings at the same time every day in order to get an average.

While this is not an absolute science, as your soil improves, so should the nutrient density of your plants.

7. Albrecht Test

If you want a highly detailed analysis of your soil, you can send it off for scientific testing by completing an Albrecht test. This test will also show you how much carbon is being stored in your soil.

This is the test that showed us how much our Wardington Manor garden had improved.

Why Test Your Soil?

Testing your soil helps you to get to know it and learn to understand it. Not only will you discover the type of soil that you have - whether it's acidic or alkaline for example - you will also begin to understand what condition it's in and what it needs in order to thrive.

What if My Soil is (of) a Very Poor Quality?

If you have poor soil, try and look at it as a challenge. By following our advice, with time and care the condition of your soil will begin to improve and you will be able to see progress.

Why not try?

• Record what you learn about your soil in the tables below.
• This way, you can see how it improves over the years and how long this process takes.