The graceful and vibrant green leaves of Calathea make it a staple of interior décor. Its long, green leaves create gentle arches, often with variegated stripes that run the entire length of the leaf.
When grown in the ideal conditions, Calathea can grow very quickly and achieve maturity within the span of a year.
A distant cousin to the Maranta genus, Calathea plants hail from South American jungles, where they are used to thriving under the shadow of towering leaves and trees where they receive little to no sunlight. This also explains why the Calathea is often referred to as a shadow plant.
Using the right Calathea soil mix is absolutely essential for growing lush and vibrant plants. Let’s take a look at the best soil mix for your Calathea so that you can provide it with all the vital nutrients it needs for healthy growth.
Best Soil for Calathea
Table of Contents
Without any further ado, here’s the best potting mix for Calathea plants:
● 1 part perlite mixed with 1 part organic houseplant soil and 1 part orchid bark or coco coir.
So what’s special about the above soil mix?
This soil mix is efficient at retaining moisture while also draining exceptionally well. Moreover, it has just the right amount of acidity with a pH value of about 6.5. The soil mix allows the plant to absorb all the nutrients it needs to grow.
Below is a deep dive into the ideal soil mixes for Calathea plants.
Why You need the Ideal Soil for Calathea Plants
We all know the role that a healthy soil mix plays in plant growth, but why is it so important?
For starters, soil allows plants to access nutrients, oxygen, water, and anything else it needs to grow and thrive.
The right soil mix will support the plant’s roots and ensure that its growing conditions are optimal for the specific species to flourish.
You can’t just use any soil mix with Calathea plants. Soil requirements depend on the type of plant. For example, some plants have very specific pH requirements, while others need a specific moisture level.
This is why using the correct soil is essential for houseplants.
Moreover, failing to provide the Calathea with the right potting mix will make it prone to overwatering, even if you’re carefully checking for moisture levels.
Waterlogged soil is bad news for just about any plant, and Calathea is no exception. When the soil has excess water, the entire plant begins to drown, and the roots start to get damaged, leading to root rot.
This will cause wilting, yellowing, stunted growth, invite pests, allow mold to flourish, and cause root rot – usually the final stage in any plant’s death.
Another problem is that you unintentionally provide the Calathea with less water than it needs for growth if you provide it with the wrong soil mix. For example, if you provide it with loose soil, then any water you provide will drain out very quickly, depriving the plant of moisture.
The plant also needs adequately aerated soil, besides moisture retention and moisture drainage holes. It is essential for air to circulate within and throughout the soil to help it breath.
Tell Tale Signs You’re Using the Wrong Soil Mix for Calatheas
Because the soil mix will directly affect the health of your Calathea, you should be able to quickly identify if something is wrong.
Consistently Wet Soil
The rate at which your Calathea plants absorb water from the soil will depend on the climate and will get progressively slower during the winter months.
On average, the Calathea plant should be able to absorb all the moisture from the soil in one week.
But if you notice that the soil is failing to stay moist for a longer period of time, then it is very likely that your soil isn’t draining enough or is too constricted for the roots to spread out and absorb all the water it needs.
The finger test is the quickest way to tell if your Calathea needs water. All you have to do is place your finger into the topsoil about two inches to get a ‘feel’ for the moisture levels. If the soil is dry, then it’s time to water the plant and vice versa.
The soil should give way to your finger with no resistance at all. But if you face difficulty in placing your finger into the soil, or the soil feels more like clay, then it is likely that the soil has become too dense and needs to be loosened.
A dense soil will choke your plant and suffocate its roots. It can also increase the likelihood of overwatering, which can easily lead to root rot and cause the plant to die.
Slow Growth of the Calathea
The Calathea is a fast-growing plant that grows at a rate of 2 inches per month in the summer months. You will be surprised just how quickly that plant catches up in size.
So if you notice that the plant has slowed its growth, then it’s time to inspect the soil. Slow growth usually indicates that the plant needs to be repotted in a different soil.
Note that this should not be confused with slow growth in the winter months. This is completely normal.
Bad Smell Coming from the Soil
A soil that fails to drain will cause the organic materials in the mix to start rotting. This will lead to a bad smell that could fill the entire room.
If you notice a bad smell wafting from the soil, then it’s a tell-tale sign that your plant needs to be repotted right away because it is at risk of dying.
Once you have determined that your plant doesn’t have adequate soil mix, it’s time to start looking for a new soil mix.
You should find that a general-purpose potting soil from your local garden center will suffice. But we recommend inspecting the soil more carefully.
Which Potting Soil Mix Should You Choose for Calathea Plants?
There are a few factors that you should consider before choosing soil mixes for your Calathea plants.
Ensure That the Soil Drains Properly
Drainage is absolutely essential for growing Calathea plants. The ideal soil mix should not only retain moisture but also drain out unneeded water. The roots should not dry out too quickly or get waterlogged.
The ideal soil mix should allow water to pass through it easily while preventing water retention that could lead to diseases such as root rot.
The best soil for Calathea includes organic materials like mulch, compost, perlite, and vermiculite. These materials play an important role in loosening the soil and preventing water retention.
Try to provide the plant with a balanced soil that can retain moisture while quickly draining water to ensure that the roots are getting all the hydration they need without getting waterlogged for too long.
pH Level Calathea Plants
The potting mix for Calathea should have a pH level of about 6.5. The acidity level of the soil should be low and not too excessive otherwise, it will cause the growth of various bacteria that could invite pests and compete with the plant for nutrients.
The good news is that you can easily adjust the soil’s pH value by using limestone to increase it or peat moss to lower it.
In addition, we recommend using a pH meter to correctly test the pH level of the soil. A cheaper but less reliable method is to buy a pH test kit.
This method involves scooping out a small sample of the soil and placing it in the kit.
The kit will change its color in response to the soil’s pH value. Look at the package label to see which color corresponds to which pH level.
A key disadvantage of using this method is that pH test kits will give you a wide range of values that could make it difficult to make an informed decision.
Moisture retention is crucial when it comes to choosing potting soil for Calathea plants because it allows the plant to receive enough water for growth.
On the one hand, if the potting mix holds too much water, the Calathea will be prone to root rot.
On the other hand, if the potting mix drains too quickly, the plant will become dehydrated and turn an unsightly shade of brown.
Adding some organic matter to the soil can improve water retention. This will ensure that the plant is receiving enough water when the ambient air doesn’t have enough moisture levels. Once again, you need to strike the right balance between moisture retention and soil drainage.
Nutrition Rich Soil Mix
Nutrient-rich soil is important for your Calathea plant and will help it not only survive but also thrive. The potting soil should have high levels of potassium, nitrogen, and phosphorus – all of which are essential in keeping your Calathea healthy. Most soil mixes will have this information on the packaging, so it’s easy for you to compare different brands.
In case you choose a soil with low nutrient levels, you can always supplement the soil by adding compost to the surface of the soil. This will then be broken down by bacteria to produce nutrients. Or you could feed fertilizer to the soil – but make sure not to overdo this because it could lead to fertilizer burn.
The Best Soil for Calathea
The best soil for Calathea consists of coconut coir, orchid bark chips, worm castings, activated charcoal, and perlite. This combination provides the ideal levels of organic matter to the plant, happens to create a well-draining soil, and has a semi-neutral pH value.
Additionally, the presence of pine bark chips and orchids can improve drainage and aeration. Finally, you can consider adding worm castings to serve as a natural fertilizer for the plant.
The Ideal Ratio of Ingredients in the Soil Mix
Here’s the ratio of each ingredient:
● 25% orchid bark
● 25% coconut coir
● 15% activated charcoal
● 10% worm castings
A Brief Look at Soil Ingredients for Calathea
The main ingredient in potting together a soil mix for your Calathea is something coarse that will help increase both aeration and drainage. Let’s take a look.
Bark chips are available in different forms, from thick chunks to fine shreds. They are listed as orchid bark and are a popular choice for orchids. They come from conifer trees and can acidify the soil, which your Calathea will adore.
Perlite is a lightweight granular material that is commonplace in most potting soil mixes. It is made of volcanic glass that plays an important role in retaining moisture. Some of its more coarse varieties are ideal for aerating your growing medium,
Coconut coir, or coco coir, is an excellent alternative to peat moss for preparing a soil mix. It is great for water retention and naturally improves moisture drainage. It can also increase the intervals between watering sessions.
Pumice is very similar to perlite but is available in bigger chunks. It is used to increase drainage and keeps the soil from getting too wet, and prevent root rot.
This item is often confused with peat moss. However, sphagnum moss is less nutrient-rich with a more neutral pH value. However, its water rendition properties are similar to peat moss.
Compost is ideal if you want to add some organic matter to the potting soil for Calathea. Worm castings are always a good choice for your plant.
Putting the Calathea Soil Mix Together
You may want to experiment with different soil mixes for your Calathea plant. Just make sure to stick to the ratios mentioned above, and your Calathea will grow well.
But before you get started, put on some garden gloves and gently mix all the ingredients in a large plastic tub. Always work in a ventilated environment when working with perlite. Consider protecting your face with a mask to ward off the dust given off by perlite when you’re pouring it out.
Ideal Store-Bought Soil Mixes for Calatheas
So you don’t want to do all of the above and want ready-made store-bought soil that contains all the necessary ingredients? Consider buying a soil mix that is intended for use with African violets. These bell-shaped flowers thrive in similar conditions and have almost the same watering needs as Calatheas.
You may also want to use a cactus soil mix with your Calathea, but this isn’t recommended. This is because cactus soil is too dry and doesn’t provide the ideal elements for optimal growth. If you must use cactus soil, consider adding potting soil, compost, and bark chips to improve water retention.
As you experiment with different potting mixes for your Calathea plant, you will learn that it is very adaptable and can survive just about anything. With that said, we recommend using the best Calathea soil mixes, as discussed above, to maximize the plant’s growth and ensure that it has a healthy life.