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Plant flowers in clay granules instead of potting soil – Why this houseplant substrate is a better choice

Even the best potting soil does not protect against waterlogging, mold or even pests. Therefore, how about using a substitute for potting soil instead? How to do this? Clay balls turn out to be a wonderful alternative to avoid all the mentioned problems. We’ll explain why it’s so beneficial to use clay pellets instead of potting soil as a houseplant substrate, and how exactly you apply it. So, if you’re planning to transplant your flowers soon anyway, consider clay pellets! So, what are the advantages of planting plants and flowers in clay granules and what are the disadvantages?

Why you can use clay granules to pamper plants

What is granules of clay?

Planting flowers in clay granules - tips for the alternative to potting soil

First of all, we would like to clarify: What is clay granules actually? This interesting substrate is ground and then granulated clay, which is finally fired, which even improves its properties. It brings some advantages in contrast to the classic potting soil – both for the plants themselves, and for the passionate plant fans. What exactly do you benefit from when you plant your plants in clay granules?

Avoiding pests and root rot with fired clay granules

  • Clay has the wonderful property of retaining water. This is perfect if you want to grow your plants in hydroponics, and in principle this is possible for all plants, including cacti and orchids, which actually prefer dry soils and substrates. In addition, you will then have to water your plants less often.
  • The air-permeable indoor plant substrate prevents the formation of fungal spores, which is particularly beneficial for allergy sufferers. With plants in clay granules, mold is thus a thing of the past. You can remove mold from potting soil, but it is better not to let it happen in the first place.
  • The houseplant is less attractive to pests. Many pests need soil to lay their eggs in (fungus gnats, for example), so potting soil naturally attracts them. If you plant your plants in clay pellets instead, you will no longer have this problem to worry about.
  • Growing plants in clay balls will also prevent waterlogging and thus mold on the roots, i.e. root rot, because the substrate is permeable to air. The perfect drainage!

Clay granules how to use?

What are the types

Clay balls as a houseplant substrate come in different sizes

Granules are distinguished on the basis of three properties: its pH and salinity, grain size and to what extent it is suitable for which plants. Accordingly, of course, you decide whether you can plant your flowers in clay granules, and if so, what kind of clay granules to put which plants.

If you want to repot your plants in clay granules, a grain size of four to eight millimeters in diameter is usually recommended. These grains are small enough to provide the plant with a stable base in which it can root well. However, the small grains also allow less air to penetrate. For this reason, you should also choose a substrate of larger grains (e.g. 8 to 16 mm) for larger houseplants.

Cultivate plants in clay granules instead of soil - what are the advantages


A neutral pH of 7 is best for most plant species. Plants that prefer acidic soil can thrive in Seramis. You should also check with regard to salt content, as the optimum level varies depending on the plant.

Should plants be planted only in clay granules or used as a supplement to potting soil?

Clay granules for plants retain water and reduce the amount of water given

Both are possible. For the already mentioned hydroponics, use only granules. In it, the roots can spread perfectly and at the same time you get a perfect drainage for the plants. However, the planting granules can also be used in addition to potting soil. We explain:

Planting flowers in clay granules - instructions for hydroponics only with clay balls.


Only with clay balls (it is best to repot the plants and flowers in the spring):

  • The pot should be larger than the previous one and also waterproof.
  • Fill it one-third with the granules for plants. On this clay granules immediately plant the plant in the pot.
  • Take the plant out of the old soil, shake it off and rinse the roots completely so that no more soil sticks to them.
  • Place the plant on the granules, leaving a few inches clear to the edge.
  • Insert the watering indicator into the substrate.
  • Fill the empty spaces with granules and press everything down a little.
  • During the next few weeks, the roots are still growing.

Water only when the indicator shows the minimum. The maximum should be selected only when, for example, you will be absent for a long time. Otherwise, the air permeability will be disturbed and the roots may begin to rot.

Combine potting soil and granules of clay - how to do it.

Clay granules for plants – use as a supplementary substrate (repotting is best in the spring):

  • Use a waterproof and larger pot than before.
  • Fill it one third with clay granules.
  • Remove the plants from the old pot and shake off some of the soil (not completely).
  • Place the plant with the root ball on the granules.
  • Fill the free areas with more granules.
  • Also spread a layer of clay granules about 2 cm thick on the surface of the root ball.
  • Insert a watering indicator into the soil.

How to grow plants in clay granules complementary to potting soil

You will get a water reservoir and drainage at the same time. Therefore, you can also offer clay granules plants as a bottom layer (like a layer of gravel) and above it plant your houseplant with potting soil as usual.

Disadvantages of clay granules application for plants without soil

Each plant should have a water indicator to determine the right time for watering

If you use clay granules instead of soil, you should be aware that the granules cannot provide plants with nutrients. So while these are stored in potting soil and gradually released, that is not the case here. Therefore, you will also need to fertilize the plants more often with the addition of water, and this, of course, comes at an additional cost. So when deciding clay granules or soil, you should also consider this fact and weigh whether you want to and can accept this disadvantage.

With potting soil, it is also relatively easy to see when it is time to water again. However, if you plant plants in clay granules, things look different. For this reason, each pot also needs a so-called watering indicator, with the help of which it becomes apparent when watering should take place.

The granules are also suitable for orchids and cacti