Last updated: August 8, 2021

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Welcome to our big potting soil test 2021. Here we present all the potting soil varieties we have tested in detail. We have compiled detailed background information and added a summary of customer reviews on the web.

We would like to make your purchase decision easier and help you find the best potting soil for you.

You will also find answers to frequently asked questions in our guide. If available, we also offer interesting test videos. Furthermore, you will also find some important information on this page that you should be aware of when buying potting soil.

Contents




Summary

  • Potting soil is an industrially produced substrate for the rapid and healthy growth of plants.
  • The soil usually consists of organic ingredients such as lime, peat or compost.
  • Potting soil is usually available ready to use and provides a starting fertiliser for growing plants that lasts for a few weeks.

The Best Potting Soil: Our Choices

Guide: Questions you should ask yourself before buying potting soil

What is the purpose of potting soil?

Classic potting soil usually does not provide the necessary ingredients and structure for plants to thrive in the long term. In addition to light, warmth and water, plants also need a nutrient-rich, high-quality soil.

Potting soil is therefore a perfect aid for planting. However, classic potting soil is different from growing soil. The latter is mixed particularly finely and only a few fertilisers are added, which benefits seedlings and seedlings.

Potting soil, on the other hand, is the right choice for plants that need to be repotted. Potting soil is intended as a fertiliser for the initial care of plants; after some time, they need to be re-fertilised.

For this purpose, there are also natural fertilisers such as primary rock flour. Contrary to the name, potting soil is not only suitable for flowers. Potting soil is also often called universal soil and is suitable for most pot, indoor, tub and balcony plants.

Success as a gardener depends largely on the right potting soil. (Source of image: pixabay.com/ Hans)

Potting soil is a humus-rich substrate. It is used for the rapid and healthy growth of plants and provides them with the necessary nutrients.

How is potting soil made?

Potting soil is an industrially manufactured product. It is a humus-rich substrate that contains lime, peat, fertilisers and various additives. Wood fibres, bark or compost can also be added. Peat is already being replaced in many cases, as its decomposition is harmful to the ecosystem.

There is also potting soil made from recycled materials. Potting soil can also be mixed with sand, which makes it particularly suitable as a substrate for drought-loving plants. There are also specially designed mixtures for cacti.

What is potting soil made of?

Potting soil consists mainly of organic components, often compost, humus or peat. Other ingredients such as clay minerals, quartz sand or perlite are also added.

Lime is used to regulate the pH value and a certain amount of fertiliser keeps the plants supplied with nutrients.

A pH value below 6.5 means acidic soil, some plants need this. With a pH value between 6.5 and 7.5, a soil is called neutral. From 7.5 and higher alkaline.

How much potting soil should I buy?

Potting soil is usually available in 5 to 50 litre bags. Depending on how much soil you need, you should make your choice taking into account the durability of the soil.

How much does potting soil cost?

One litre of potting soil can cost between €1.50 and €10. Price does not necessarily correlate with quality.

What are the alternatives to potting soil?

As an alternative to potting soil, you can also use plant granulate. This is an inorganic product that prevents the formation of mould, stores water longer, requires less repotting and allows the plants to grow vigorously.

Type of soil Properties
Potting soil water capacity, air capacity, free of pests, pathogens and weed seeds, high nutrient content, pH value
Plant granulate inorganic, wide range of products, water-holding capacity, high nutrient content, makes plants grow more vigorously, mould and pest resistance, rarely needs repotting
Coir potting soil environmentally friendly, water-holding capacity, mould resistance, mineral nutrient supply, gives plants oxygen, high air permeability, no heavy metals

Another alternative that is becoming increasingly popular is coconut soil. This is a renewable raw material that does not contain heavy metals. Coconut soil also has good water retention properties and reduces the need for watering. The coconut fibres themselves can also be used as a protective cover against weeds.

Decision: What types of potting soil are there and which is right for you?

A distinction is made between the following types of potting soil:

  • unfertilised potting soil
  • fertilised potting soil
  • Potting soil with peat
  • Potting soil without peat
  • Potting soil

We would like to help you with the following section to make your decision easier so that you buy the potting soil that suits you best.

What are the characteristics of unfertilised potting soil and what are its advantages and disadvantages?

Unfertilised potting soil can be particularly useful if you want to mix your own soil and control what is in your soil and how much fertiliser is added.

Advantages
  • Amount of fertiliser can be determined yourself
  • Can also be used as garden soil
  • Purity
Disadvantages
  • No nutrients contained
  • Effectiveness must first be created

What distinguishes fertilised potting soil and what are its advantages and disadvantages?

Fertilised potting soil offers a problem-free starting package for plant cultivation. Most of the growth-promoting nutrients and fertilisers have already been added. There are suitable variants for the respective plant species.

Advantages
  • Nutrient content tailored to the needs of the plants
  • High-quality ingredients
Disadvantages
  • Unwanted substances may be contained
  • Rather unsuitable for trees and shrubs

What are the advantages and disadvantages of potting soil with peat?

Potting soil with peat has become known in many mouths as no longer recommended for purchase. The reason for this is the environmentally harmful extraction of peat, which consists of the draining of moors, which irreparably destroys the habitat of many animal and plant species.

But peaty potting soil also has disadvantages when it comes to application. For example, the peat acidifies the soil, which means that nutrients have to be added again. You also have to water this soil more often, as peat has a drying effect.

This is made easier by automatic watering systems. Even if peat soil is labelled as low peat or peat-reduced, the peat content can be very high, so this is not an alternative if you want to make sure you garden peat-free.

Advantages
  • Very conducive to growth, absorbs a lot of water
  • Good for plants that prefer acidic soil
  • Good for lime-loving plants
Disadvantages
  • Extraction is harmful to the environment
  • Returns little water
  • Dries out soil
  • High acidity
  • Needs to be re-limed in cases

Environmentalists advise against peat-based potting soil, as peat is extracted at the expense of peatlands, which in turn provide valuable habitats for animals and plants.

What distinguishes peat-free potting soil and what are its advantages and disadvantages?

Potting soil without peat is now available everywhere. The peat content is replaced with bark humus, compost or coconut and wood fibres. These substances are also very conducive to growth and environmentally friendly.

Advantages
  • Environmentally friendly
  • Equally good growth result
  • No liming
Disadvantages
  • Additional fertiliser for plants that need high acidity
  • Nutrients decompose faster
  • Less water absorption

What distinguishes growing soil and what are its advantages and disadvantages?

Growing soil can be distinguished from conventional potting soil. It is very finely mixed and only small amounts of fertiliser are added. Since seedlings and sprouts are very sensitive, potting soil is best suited for this purpose.

It usually consists mainly of humus and sand. This soil is not only cheaper to buy, it is also airier and looser, can store a lot of water and thus provides plants with sufficient moisture and oxygen.

Tip: You can also use a plant lamp in addition to the growing soil to make your plants grow faster.

Advantages
  • Little fertiliser
  • Optimal for seedlings and seedlings
  • Inexpensive
Disadvantages
  • Little fertiliser
  • Not suitable for plants that need a lot of nutrients

Buying criteria: You can compare and evaluate potting soil based on these factors

Benefits

If you want to use potting soil for balcony or container plants, you need a particularly good flower fertiliser that provides the plants with enough nutrients despite growing in a small space.

For indoor, balcony and garden plants, a water-retaining potting soil is advantageous. Herbs, on the other hand, thrive better in soil that is rather low in nutrients. There are also plants that cannot cope with lime, such as rhododendrons, for which lime-free peat soils with a low pH value offer advantages.

Potting soil does not ONLY help flowers to thrive. It provides a good nutrient base for many plants, apart from trees and shrubs. (Image source: pixabay.com/ congerdesign)

Cost

The more expensive potting soil is, the more specialised its purpose. A 20l bag can cost between 1.50 and 10 euros. Price does not necessarily stand for quality, yet good soil has its price.

Quantities

The quantity refers to the volume and not the weight. One m³ of potting soil weighs about 400-500 kg. At the same time, 1m³ corresponds to 1000 litres. Potting soil is usually available in quantities of 5 to 50 litres.

Labelling

Some potting soils are labelled with the RAL seal of the Quality Association for Substrates or with a reference to the Research Institute for Organic Agriculture (FiBL). This is in any case an indication of quality. Organic soil does not necessarily mean good quality, nor does it always indicate environmental friendliness.

Ingredients

Your preferred potting soil should contain sufficient nutrients such as phosphorus, potassium or nitrogen. If you are concerned about environmental friendliness, you should avoid peat in your potting soil.

Facts worth knowing about potting soil

What is the shelf life of potting soil?

Potting soil can be used for up to six months as long as the package is tightly sealed. After that, however, the important nutrients have already been broken down. With compost-containing organic soil, the nutrients decay earlier.

How do I store potting soil?

Potting soil in its packaging should be protected from the weather, such as sun or rain, and stored in a cool, dry place. Nutrients can be lost if the potting soil is heated above 30°.

Where do I dispose of potting soil?

In principle, you should not regard "old" potting soil as waste, because you can reuse it in the garden in other ways. You can compost depleted potting soil or add it to your garden soil, which increases humus retention.

For example, old potting soil can be used for mulching, mounding, insulating, or you can store it temporarily, and you will certainly be able to use it for other purposes at some point.

What should I do if my potting soil becomes mouldy?

You should remove the mouldy soil completely and dispose of it in the household waste. The plant itself should also be cleaned. To do this, remove the clumps of soil at the roots and rinse the leaves and roots with lukewarm water.

Then you can fill the pot with fresh substrate. Tea tree oil in the water or sprinkling the soil with activated charcoal or cinnamon is also said to be effective against mould. The reason for mould is always too much moisture in the soil.

If a plant is affected by mould, you must remove it, including the roots. (Image source: pixabay.com/ Free-Photos)

How do I rid potting soil of pests?

Plant protection products are particularly successful in the fight against mosquitoes and flies. You can buy these as sprays, liquids or granules. Electronic traps can also be set up or baits with adhesive layers.

To prevent pest infestation, you should keep an eye on the moisture content of your soil, as infestation is particularly likely with excessive moisture. Regular fertilisation and the appropriate nutrient requirements of the soil of the respective plants also play a major role in the resistance to pests.

Why do dogs eat potting soil?

It is not uncommon to catch dogs eating soil. If your dog does this, he may be lacking digestive enzymes or the microflora of the intestine may be impaired. This can be the result of an unbalanced diet or a change in diet.

Antibiotics or worming treatments can also reduce the diversity of the intestinal flora. The dog then tries to compensate for this by ingesting soil, sometimes also feces. If you want to stick to home remedies, you can give your dog more fibre, aloe vera gel or the well-known healing clay.

In the meantime, there are specially developed products on the market that bring your dog's intestinal flora back into order. Homeopathic remedies such as Bach flowers or Schüssler salts are also said to be successful.

How often do I have to change my potting soil?

To be on the safe side, the soil of potted plants and balcony plants should be changed once a year, but at the latest every two years it should be replaced with fresh potting soil.

How and when do I fertilise potting soil?

Potting soil is often very poorly fertilised or you may even have bought the unfertilised variety. Usually potting soil contains a starter fertiliser that lasts up to eight weeks. If you use the soil for houseplants and balcony plants, you should fertilise it after four to six weeks.

You should pay special attention to nitrogenous fertiliser and to the fact that it can be used in the long term. There are, for example, depot fertilisers that only release the fertiliser over time, are not washed out so quickly and reduce the risk of overfertilisation.

You can also use your own compost for fertilising or add a fertiliser to the water you pour. The packaging of the potting soil should indicate how much fertiliser it contains. The following table shows you an overview of the labelling:

Labelling Amount of fertiliser Suitability
Type 0 no fertiliser sensitive seeds
Type P little fertiliser sowing seeds, cuttings, transplanting young seedlings
Type T rich in nutrients tubs and larger plants

Can I make potting soil myself?

Yes, you can make your own potting soil relatively easily. You need to mix compost, charcoal and micro-organisms. You should make the mixture from late spring to late summer, when the temperature does not drop below 15 degrees.

You can use compost that has already rotted, but it should be free of disease and pests. You also need a large container that can be sealed airtight.

Compost alone is not a suitable substitute for high-quality potting soil. Since compost acts like a fertiliser, excessive use can also lead to an over-supply of the soil. The soil can be mixed with compost in a 2:1 ratio.

A variation on making your own potting soil is to fill the container 2/3 full with compost and sprinkle stone dust as a mineral component between each layer. It is also advisable to add a 10-percent proportion of pollutant-free charcoal to the mixture.

The homemade potting soil can be optimised with microorganisms; these EM products are available in organic food stores, for example. Now mix everything well, seal it airtight and leave it to rest for 2 weeks.

After that, you should choose an area in the garden that has natural soil, then loosen it up a bit, spread the mixture and cover the whole thing with garden soil again. Then cover the area with plastic sheeting and weigh it down with stones.

Then you can leave the nutrient soil to rest for about half a year (preferably during the winter) and in spring you can turf it over again and start sowing.

Another product recommended for addition is coconut fibre substrate, which is said to be particularly suitable for growing young plants from seeds or cuttings and improves the permeability of water and air.

Image source: unsplash.com / Krystina Rogers

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