Do you want a cookie?

Green thumbs, watch out! We use cookies on our website - not the delicious ones for snacking, but the digital helpers. They enable us to find out how our website is used. If you click on "Accept", our virtual garden gnomes will be happy and promise to guard your data like their own watering can. You can find more information in our Privacy Policy.

Simple soil test: Determine soil type & quality

Simple soil test: Determine soil type & quality

Last updated: 20.01.2025
Reading time: 4 minutes

When choosing the right vegetable plants, the type of soil you have in your garden is crucial. The soil texture also influences how often you need to water and fertilize in summer. To determine the soil texture of your garden, there are two key parameters: the particle size and the humus content.

This Article Contains:

  1. Testing soil quality: the sludge sample
  2. 1) Determine soil type with the sludge sample
  3. 2) Determine humus content using the sludge sample

Testing soil quality: the sludge sample

With the finger test, you can easily determine your soil type without any tools. On the one hand, you can determine the particle size and therefore the composition of your soil. On the other hand, you can use the color to find out the humus content of your soil.

1) Determine soil type with the sludge sample

The type of soil is defined by the particle size, the so-called grain size. The particle size is a good indicator of whether your soil is heavy or light. The larger the particles, the lighter. If you have a lot of fine clay particles in your soil, it is a heavier soil. It holds water longer, a great advantage in dry summers. In addition, heavy soils are often richer in nutrients than sandy soils. You can find more information about heavy and light soils here.

Understanding soil composition: Granulation and grain sizes

Grain size Particle size
Stones and gravel > 2 mm/ 0,07 in
Sand 0,05 - 2 mm/ 0,002 - 0,07 in
Silt 0,002 - 0,05 mm/ 0,00007 - 0,002 in
Clay < 0,002 mm/ 0,00007 in
Materials for the slurry sample

Materials for the slurry sample

What you need

Materials for the slurry sample

Materials for the slurry sample

- Large beakers or screw-top jars for the samples
- Your soil sample
- water
- Spoon or spade

Instructions: How it works

To find out the particle size, fill a handful of soil from your bed into a jam jar. Fill the rest of the jar with water, close it and shake vigorously until all the clumps of soil have dissolved. Then leave it to stand for one to two days. You should now see two layers at the bottom of the jar. A coarse-grained, sandy layer at the bottom and a finer layer of clay particles on top. If the finer layer is significantly thicker than the sandy layer, the soil is rather heavy. In optimal garden soil, both layers are approximately the same thickness. If the sandy layer is thicker, the soil can be classified as light.

Sludge sample to determine soil type
On the far right is the result of the test: the coarse and fine layers are roughly the same thickness. An indication of a good soil composition. Photo by Gabriel Jimenez on Unsplash

2) Determine humus content using the sludge sample

The color of the soil provides information about the humus content of the soil. The blacker the soil is when moist, the higher the humus content. A high humus content means that the soil is rich in nutrients, has a healthy soil life and can also absorb and retain a lot of water. Dark, humus-rich soil is particularly suitable for growing plants with high nutrient requirements. These so-called heavy feeders include, for example, various cabbage plants or tomatoes. If your soil is light brown in color, you should increase the proportion of organic matter in the soil. You can do this by mixing in mature compost, for example. You can find detailed information on soil improvement here.


If you have any questions or comments, please write to us at [email protected]. Would you like to receive helpful gardening tips all year round and plan your own beds optimally? Then register here or download the Fryd app for Android or iOS.

Fryd - Your digital bed planner


author image
Author

Jonas

Jonas studied agricultural biology. He discovered his passion for plants and gardening through an internship at a permaculture NGO. Since then, he has been gardening on his balcony and in community gardens.

Learn More

Current Topics in the Community

Avatar
Plakakia 1 hours ago
I like
Respond

Liked 1 times

I'm also becoming more and more of a no-dig gardener 😄 The last beds that are not yet covered are first given a layer of leaves and/or grass cuttings and then a layer of hay on top. I've never done it as consistently as this year before. I'm curious to see if it works! Second picture: the strawberries now also have their layer of hay. And at the front left of the bed I've started mulching with leaves from the endive. Unfortunately it was already starting to rot. I've hidden the remaining heads, which are still good, under green foil at the back right. So that they don't get so much moisture from above.

Avatar
MamaVonJungemGemüse 5 hours ago
I like
Respond

Liked 6 times

A few days ago, I planted my first bed à la "no dig". Not least because I recently got a peony in the great garden where I was allowed to help myself. Now my great-grandmother's peony 💫 (front) has company from the gift and a discount store plant (not in the picture), which for 3 years lamg lived its existence in a place only slightly better than the discount store 😄 (under the birch, in the shade, oppressed by goutweed and often "beaten down") In addition, I planted a remaining Christmas rose, remaining evening primroses in their first year and finally the spring bloomers (wild tulip, hyacinth species, large-flowered crocus) from Bingenheimer Saatgut. Hopefully more mullein will settle behind them. I'm looking forward to the result!

Show 2 answers
Avatar
MamaVonJungemGemüse 5 hours ago
I like
Respond

Liked 7 times

Bird food production is on the agenda today. The greenhouse still hasn't been completely tidied up and the winter lettuce still hasn't been sown, but it's time for what burns brightest 🤪: Currently preparing for the kindergarten stand at the Christmas market 💫

Show 1 answer

Register for Free

You can quickly and easily register for free in our mobile app and use many more features.

These include:

  • Access to our community
  • Free mixed culture bed planning
  • Database with over 3,000 varieties of vegetables

Have You Heard of the Fryd App?

From growing to harvesting - plan your vegetable garden with Fryd

Put an End to the Garden Guessing Game

Generic tips and seed-packet dates are broad averages, while seasons and microclimates shift from place to place. Run or join experiments, log simple observations, and share results in Fryd Lab.

Register for Free

You can quickly and easily register for free in our mobile app and use many more features.

These include:

  • Access to our community
  • Free mixed culture bed planning
  • Database with over 3,000 varieties of vegetables

Don't waste precious growing space

Plan your companion plantings now for healthier, more resilient plants and harvest more than ever!

Sign up for Free

Subscribe to Read on

Put an end to the garden guessing game. Fryd is your Garden Companion, providing you with tons of valuable advice, digital tools to help you grow as well as the best garden community.