If you've ever looked up "monstera soil mix" online, you've probably found a dozen different recipes and come away more confused than when you started.
Some people swear by pure coco coir. Others use mostly perlite. Some have elaborate five-ingredient blends with things like activated charcoal and worm castings measured out precisely. It starts to feel like you need a chemistry degree just to repot a plant.
Here's the good news: it's simpler than the internet makes it look. The goal is the same for almost every aroid, whether that's a monstera, philodendron, pothos, or anthurium. You want a mix that drains fast, holds a little moisture, and lets air reach the roots. Once you understand why that matters, making a good mix is straightforward.
Why Standard Potting Mix Isn't Enough on Its Own
Regular potting mix from a hardware store is designed to hold moisture. That's great for a lot of garden plants. But aroids need more drainage and air around their roots than standard mix provides.
When you water a pot of straight potting mix, the water doesn't drain quickly. It sits in the mix for a day or two, sometimes longer. During that time, the roots have no access to air. They're sitting in wet, airless soil, which is exactly the environment that leads to root rot.
Most aroids in their natural environment grow in loose, chunky debris: rotting wood, fallen leaves, bark. Their roots move through material that has big gaps in it, where air circulates freely and water drains fast after rain. The mix in your pot needs to work similarly.
You don't need to create something complicated. You just need to make the standard mix chunkier and faster-draining.
The Base Recipe
Here's a solid all-purpose mix that works well for monsteras, philodendrons, pothos, and anthuriums:
- 40% bark
- 30% potting mix
- 20% perlite
- 10% worm castings
This is a starting point, not a rule. You can adjust it based on what you have and how your plant tends to behave. But if you stick roughly to these proportions, you'll have a mix that drains well, holds enough moisture, and gives roots room to breathe.
What Each Ingredient Actually Does
Bark (40%)
Bark is the main structural ingredient. The chunks create large gaps in the mix, which is where most of the air around the roots comes from. Bark also holds a small amount of moisture on its surface, so roots can drink without the mix staying soggy.
The key is using bark that stays chunky. Cheap bark from a garden centre often breaks down within a year, turning into a dense, compacted mass that defeats the whole purpose. Orchiata bark is aged New Zealand pine bark that holds its structure for 3 to 5 years. For a monstera or large philodendron, the Classic grade (6-9mm) or Power grade (9-12mm) works well. For smaller plants like pothos or anthurium, the Precision grade (3-6mm) gives you the same benefits in a finer size.
Potting Mix (30%)
Regular potting mix fills the gaps between the bark chunks and holds moisture so the mix doesn't dry out too fast. Without it, a pure bark mix can drain so quickly that the plant dries out within a day or two. You still want some water-holding capacity.
The potting mix also contains some base nutrients from the organic matter in it, which gives young roots something to access immediately after repotting.
Perlite (20%)
Perlite looks like small white beads. It's made from a type of volcanic glass. It doesn't hold water, it doesn't break down, and it doesn't add any nutrients. What it does is create extra drainage.
When water flows through the mix, perlite helps it exit quickly rather than pooling at the bottom or in dense spots. It also keeps the mix from compacting over time, which is especially useful in larger pots where the weight of the mix can press things together.
Worm Castings (10%)
Worm castings are basically composted worm waste. They're packed with nutrients and beneficial microorganisms. In small amounts, they give the mix a natural fertility boost without the risk of fertiliser burn.
You don't need a lot. Ten percent is enough to give roots a healthy environment without making the mix too rich or too water-retentive.
How to Make It
You don't need to be precise down to the millilitre. Use any container as a scoop and measure roughly: four scoops of bark, three of potting mix, two of perlite, one of worm castings. Mix them together in a bucket or bag until they're combined.
Before potting, water the bark lightly first if it feels very dry. Dry bark can be a bit hydrophobic, meaning water runs off it without soaking in. A quick pre-soak or a splash of water into the mix solves this.
Adjusting the Recipe for Your Situation
The base recipe is a good middle ground. But every home environment is different.
If your plant dries out too fast (the mix feels bone dry within a day or two of watering), add more potting mix and reduce the bark slightly. Try 35% bark, 35% potting mix, 20% perlite, 10% worm castings.
If your plant stays wet too long (still damp more than four or five days after watering), reduce the potting mix and add more bark or perlite. Try 50% bark, 20% potting mix, 25% perlite, 5% worm castings.
If you're in a humid climate (tropical Queensland or similar), err on the side of more drainage. Humid air means the mix dries more slowly to begin with, so you want it faster-draining to compensate.
If you have a small plant in a small pot, use the finer bark grade (Precision, 3-6mm). In a small pot, large bark chunks leave too little contact between roots and mix.
How to Tell If Your Mix Is Right
You're looking for a mix that drains freely when you water it (you should see water coming out the drainage holes within a few seconds, not pooling on top), then dries out within three to five days in normal conditions.
Press your finger about 2 centimetres into the mix. If it feels dry at that depth, it's time to water. If it still feels damp, wait another day or two.
After repotting, the roots should establish themselves quickly. A healthy plant in a good mix typically shows new growth within a few weeks, and you'll see roots starting to fill the pot within a couple of months.
What About Coco Coir?
Coco coir (ground coconut husk) is a common mix ingredient and it works fine. It holds moisture well and doesn't compact as fast as regular potting mix. If you have coco coir on hand, you can substitute it for some or all of the potting mix in the recipe above.
The reason this recipe uses potting mix as the base rather than coco coir is that potting mix is easier to find and most people already have some around. If you prefer coco coir, use it the same way.
The Most Important Thing
Whatever recipe you use, the mix needs to have structure. It needs to drain fast and hold some air gaps. That matters more than getting the exact ratio right.
A good bark base like Orchiata is the easiest way to get that structure, because the chunks don't break down and they create natural air gaps automatically. Everything else you add is just fine-tuning around that foundation.
Start with the base recipe, watch how your plant responds over the first month, and adjust from there. Most aroids will tell you pretty clearly when they're happy: new leaves unfurling regularly, firm stems, roots filling the pot without being cramped. Once you see that, you'll know you've got the mix right.
