How to choose soil or substrate for your houseplant

Choosing the right soil or substrate/growing medium for your houseplants can often feel like a complex puzzle. What are different substrates? Which one should I choose? These questions often arise when we face our houseplant repotting.

Thankfully, we don't have to repot our green friend very often into fresh soil, but once in a while, it's time. Then, it's really important to choose the right medium for the ultimate growth of your plant. Therefore we would like to go through the different options with you!

Different growing mediums suitable for houseplants

Regular potting soil

For many houseplants, organic potting soil is a good base to grow in. This potting soil works well as a basic substrate for a wide variety of houseplants. The standard potting soil that you can find in all garden centres is often a ready-made mix. This mix already consists of a number of substrates and substances to ensure that the soil has a good structure but also contains enough nutrients.

Usually, you will find peat, peat chunks, coconut, natural organic fertilisers and other similar ingredients in such a mix. Our favourite potting soil is composed with care and contains the following ingredients and substances:

• Peat moss
• Irish fraction (peat chunks)
• Peat fibre
• The right amount of lime (this ensures the right PH value and is a source of calcium)
• Important nutrients (NPK - nitrogen, phosphate, and potassium)
• Trace elements mix (substances that are absorbed by the plant in very small quantities)

This potting soil is a special PLNTS.com mix, and so the perfect additions have been carefully considered to ensure that your plants can grow perfectly.

Perlite granules

Perlite grains are actually small glass particles, very light and airy. It originates from volcanic areas and expands tremendously when heated to about 1300°C. This happens because the bubbles of air in the rock then escape.

Perlite ensures that the oxygen can more easily reach the houseplant roots, preventing them from becoming waterlogged or suffocated by compacted soil. Thus, its roots will develop better, and your houseplant can grow more beautiful and lush. Additionally, perlite enhances the appearance of the soil with its light grains, which also improve drainage, ensuring the soil doesn't stay too damp for too long.

Important to know! When using Perlite, dust is released, which is essentially very small glass particles. So make sure you keep something in front of your mouth or mix outside to prevent damage to your lungs.

Do you want to take cuttings from your green friends? Perlite is an ideal medium for plant cuttings and root development. It helps in retaining moisture which is beneficial for the cuttings to develop roots without getting waterlogged.

Vermiculite

Vermiculite is a high-quality clay that expands like a harmonica when heated and therefore produces very light grains. Vermiculite is non-toxic and sterile and does not deteriorate over time. It can absorb three or four times its weight in water and also attracts various plant nutrients, such as potassium, magnesium and calcium.

Vermiculite can be used alone when taking cuttings or can be mixed with potting soil. Vermiculite is very similar to perlite but is less porous.

Pumice

Pumice is very similar to perlite in its ability to absorb excess moisture and provide ideal airflow for the roots. Because pumice has many holes, it can store fertiliser quite well, making it great for feeding your plant. While perlite is a volcanic glass, pumice is a volcanic rock.

You can mix pumice into your potting soil to improve its properties or use it as a propagation medium.

Expert tip! There is usually quite a bit of dust attached to the pumice. Washing it before use can prevent this dust from clogging up the soil.

(French) Tree Bark

French tree bark is a multifunctional material that not only does well in the garden. Your houseplants will be very happy with it too. The material helps to keep the potting soil moist, but it is mainly used to improve the soil's airy structure.

Tree bark is used especially frequently in soil made for Anthuriums and Orchids, or other epiphytes. These plants like to grow on other plants and are therefore used to a lot of air near the roots. By adding tree bark to your potting soil, the plant has something to 'grab onto', thus bringing a lot of air into the soil and, over time, being digested by soil organisms, which in turn provides useful nutrients.

Expert tip! You can use only tree bark as a growing medium for your epiphytes, or you can mix some bark into your soil to make it chunkier and more aerated, which can benefit many types of houseplants by promoting better root growth and drainage.

Cocopeat

Cocopeat is a waste product from coconut products, where only the milk, the meat and the hard bark are used. After a desalination treatment, among other things, this grit turned out to have very good properties to be processed in potting soil.

Cocopeat is very finely ground and perfect as a substrate in potting soil to improve soil texture, soil aeration and moisture retention capacity. These three major improvements make this a very good substrate. This cocopeat is also super for germinating seeds and as a cutting soil. This is because it can hold moisture well and thus maintain an ideal condition for your young plant or for germinating seeds.

Expert tip! When you put the cutting, seeds or maybe even your plant only in cocopeat, make sure you add enough nutrients. Cocopeat has no nutrient buffer in it.

Coconut Fiber

The name says it all - coconut fiber is a product of the coconut, namely the outer bark of the coconut. Coconut fibre is considered one of the best substrates, but it cannot be used directly from nature because of its very high salt content (so don't go picking a coconut bare yourself 😉).

Coconut fibre has the advantage that it absorbs water better than potting soil and is more environmentally friendly. We recommend that you use a maximum of one-third of coconut fibre in a potting soil mixture. It also provides optimal soil ventilation and therefore provides an airy structure and transports water through the root system. Because coconut fibres are completely organic, they also increase the organic content of the soil.

Important to know! Unfortunately, you cannot let a plant grow in coconut fibre alone because coconut fibre does not contain any nutrients which your plant needs to grow well.

Peat chunks

Peat is a wet, oxygen-deficient soil type with a sponge-like structure composed of plant material. All peat types are naturally acidic. Lime must therefore be added to achieve the right PH value for plants.

Peat is a super important component of potting soil. Especially peat chunks are good to add to potting soil. This creates an airy potting soil that can absorb water well and retain moisture. It also buffers nutrients more easily. It therefore ensures good root development and a beautiful growing plant. Actually, all plants will be happy with this addition!

Active charcoal

Active charcoal is a super addition to your houseplant soil. It actively absorbs excess moisture and gives it back on dry days, acting as a kind of moisture regulator in the soil. In addition, water-soluble nutrients are collected on unburned particles, consisting of humus and fertiliser, which are also very useful for plants.

Charcoal helps hold the loose soil and improves the porosity and permeability of the soil. Activated carbon is perfect for when you want to plant your new addition in a pot without a drainage hole. In addition, it even absorbs toxins to protect the soil and roots from bacteria and fungi. Repelling some insects is its other superpower, making it a real-life saver! This also makes activated carbon perfect if you want to make your own terrarium.

You can just combine the potting soil and the activated charcoal together. A good ratio to start with is about one part activated charcoal to 4-to 5 parts soil. Applying a layer of activated charcoal to the soil, under the soil, protects the plant from overwatering. You can crush the activated charcoal into smaller pieces if they are too large.

Hydro grains

Hydro grains make taking care of your plants much easier. They are small, lightweight clay pebbles that absorb moisture not only from the soil but also from the roots! Place them on the bottom or top of the soil so that excess water is evenly distributed throughout the soil.

Expert tip! It's also great for pots without drainage holes. Just add a decent layer of hydro grains at the bottom of the pot!

In addition, those small grains loosen the soil. This provides the roots with more oxygen, so your beauty will look its best! Hydro grains may look fragile, but they can be used over and over again. They are actually indestructible, so definitely worth buying! Hydro grains are also widely used in hydroponics and are ideal for that as well.

Sphagnum moss

Sphagnum moss improves the structure of potting soil. This macho plant can hold up to 20 times its own weight in water! This keeps the potting soil always moist, which is especially appreciated by many tropical plants.

You can mix 1/5 sphagnum moss into the potting soil of your tropical plant, and the soil will be less likely to dry out. The more sphagnum moss in your mix, the better and longer it will retain moisture. We also find sphagnum moss perfect for cuttings. Simply put your cuttings in the moss, and they will root super. When the cutting is rooted (the root of 8cm or longer), it is advisable to move it to the soil.

Expert tip! If you have some moss left over, let's get creative! Because of its flexible shape, you can easily make your own (hanging) basket or moss stick with it!

Living Moss

Living moss is an ideal substrate to use for terrariums, orchids (and other epiphytes) and for propagation. Especially for plants with fewer roots or cuttings, living moss is ideal for developing roots.

Of course, you can also use living moss for other creative purposes. It is ideal for your terrarium or to make your own kokedama ball. To maintain that beautiful green colour, it is best to use filtered water. Otherwise, there is a chance it will turn brown.

Propagation soil

We understand only too well that you want to expand your PLNTS family and grow your own babies! PLNTS Cuttings soil is perfect for rooting cuttings and eventually growing them into true doubles of your mother plant. It has a fine, compact and regular structure, which ensures an even water and nutrient supply and therefore prevents dehydration. When your cutting has developed good roots, you can repot it in normal potting soil, or you can compose a nice mix yourself!

Our cutting soil is specially mixed so that it is perfect for every cutting. It contains the following ingredients:

• Peat moss
• Perlite
• Coco peat
• Important nutrients

Vulcastrat

Vulcastrat is a substrate that is often used professionally. It is a mixture of minerals such as lava and pumice. It absorbs moisture, lots of moisture! It can absorb water up to 30cm upwards, so there is little chance of water staying at the bottom of the pot. This prevents roots from rotting, which is great. The water is gradually released to the plant by the Vulcatrat.

The rough structure also allows enough oxygen to reach the roots, making it easier for roots to grow through. Vulcastrat is a mix of various volcanic rocks and is used as a substrate in hydroponics. It contains no nutrients, so you should think about giving extra fertilisation.

Pon (Vulcaponic / Lechuza pon)

Pon is basically a smaller form of Vulcastrat but with added fertiliser. It is a brand name and is better known than Vulcastrat due to Lechuza's good marketing. The only difference between Vulcaponic and Vulcastrat is that Vulcaponic contains more zeolites. This ensures that this substrate can absorb even more water and has better air pores. Lechuza pon does contain coated fertilisers and is therefore provided with nutrients, so you can go ahead for the first few months!

How to choose growing mediums for your houseplant?

We understand that after all the explanations per substrate, you still have questions. What exactly is really good for what? We would like to help you! We have listed below what we believe is the best substrate for each use. For example, the best for an airy structure, the ideal moisture regulator, what filters impurities from your soil and what is very good for cuttings.

Please note! This is based on our opinion. You may have a different preference and experience it differently in the end.

What is the best potting mix for your houseplant?

Choosing the right potting soil depends on the plant's needs. Before you start to choose soil, look up your houseplant care guide and see what soil is like. The soil structure and nutrients are also super important. To get healthy, strong plants, the potting soil must meet the special needs of the plant. For example, in addition to a good soil structure, certain nutrients and lime are also needed in order for the plant to grow and develop. We hope the following information will help you find the perfect mix for your green friend.