🪴 Tips
🌱 Repotting
🌿 In brief
Universal potting soil suits most indoor plants, provided it is lightened with perlite. More demanding groups - cacti, orchids, carnivorous plants, aroids - need a specific mix, and this is often where the difference lies between a plant that stagnates and one that grows.
We choose our plant carefully, our pot with taste, and pour the first bag of potting soil we find on the shelf over it. Yet the substrate is what constantly surrounds the roots: it determines how much air they receive, how quickly water drains, and what the plant can absorb. Here's how to choose the right mix, family by family, and how to rescue overly compact commercial potting soil.
Why potting soil matters
A root needs more than water and nutrients: it needs to breathe. A substrate therefore performs three functions at once, and their balance is what makes a good mix.
Letting air through
Roots consume oxygen. In compacted, waterlogged potting soil, they suffocate and rot - this is the leading cause of indoor plant death.
Retain just enough water
A good substrate retains moisture for a few days, then dries out. If it stays wet for two weeks, it retains too much water for the plant or the pot.
Holding the plant in place
The mix must anchor the roots without compacting. Potting soil that settles over successive waterings eventually forms an impermeable block.
In other words, problems attributed to watering very often come from the substrate. If you feel you are watering correctly and the plant is still declining, it is the mix you need to look at - before changing your watering schedule.
What's in potting soil
A bag of potting soil is not garden soil. It is a blend of a few materials, each with a specific role. Knowing what they are helps you read a label and create your own mix.
Bases that retain water
Peat moss has historically been the basis of potting soil: light, acidic, and highly water-retentive. Its main drawback is environmental, and it becomes difficult to rehydrate once it has dried out completely. Coconut coir serves the same purpose with a better environmental impact and rehydrates easily: today, it is the base to prioritize.
Materials that allow air in
Perlite, those small white balls, creates air pockets without retaining water: it is the most useful and least expensive additive. Vermiculite does the opposite, retaining water and minerals. Composted pine bark, in pieces, provides lasting aeration and decomposes slowly - essential for aroids and orchids. Finally, coarse sand adds weight and improves drainage: reserved for cacti.
What provides nutrients
Compost and worm compost provide the nutrients. Commercial potting soils contain enough to last around six to eight weeks: after that, it is the fertiliser that takes over, not the potting soil.
⚠️ Never use garden soil
It compacts in a pot, becomes water-repellent after a few waterings, and brings larvae, seeds and fungi with it. Even though it is excellent in the garden, it is unsuitable for an indoor pot.
The right mix for each family
There is no need to buy six different bags. A basic potting soil, perlite and bark are enough to cover almost every case, simply by varying the proportions.
| Family | Recommended mix |
|---|---|
| Common houseplants Pothos, Ficus, Dracaena, Sansevieria |
Universal potting soil + 20% perlite. Simple, airy, and sufficient for the vast majority. |
| Aroids Monstera, Philodendron, Anthurium, Syngonium |
Equal parts potting soil, pine bark and perlite. Thick roots that require plenty of air. |
| Cacti and succulents | Cactus potting soil, or equal parts potting soil, coarse sand and perlite. It must dry out quickly. |
| Calathea, Maranta, ferns | Potting soil and coco coir, with a little perlite. Constant moisture without standing water. |
| Orchids | Bark alone, never potting soil. Their roots are aerial and rot in a standard substrate. |
| Carnivorous plants | Pure blond peat, or peat and sand, with no fertiliser or compost. Rich potting soil kills them. |
| Seeds and cuttings | Very light and low in nutrients: coco coir and perlite. Roots develop better in poor substrate. |
The two truly non-negotiable cases are orchids and carnivorous plants: standard potting soil is fatal to them in the short term. For everything else, adjusting the proportions is enough. Here is one plant from each major family, with the mix that suits it:
Golden PothosCommon houseplant: universal potting soil and 20% perlite are enough.View the plant →
Monstera DeliciosaLarge-rooted aroid: equal parts potting soil, pine bark, and perlite.View the plant →
Mini cactus in a terracotta potWell-draining mix with coarse sand and perlite that dries out within a few days.View the plant →
Calathea MakoyanaConsistent moisture: potting soil and coconut coir, with a little perlite.View the plant →
Improving commercial potting soil
Most budget universal potting soils are too fine and retain too much moisture: they are suitable for garden beds, not for an indoor pot. A few steps make them perfectly usable.
- Always add 20 to 30% perlite, regardless of the plant: it is the most worthwhile step.
- For plants with large roots, mix in a handful of pine bark pieces.
- Break up compacted blocks by hand before filling the pot, and never compact the mix afterward.
- Lightly moisten the mix before repotting: dry potting soil repels water during the first watering.
- Choose potting soil made with coconut coir rather than pure peat, as it is much easier to rehydrate.
A good test, once the pot is filled: pour in water. It should pass through and come out of the holes within a few seconds. If it sits on the surface or takes a minute to drain, the mix is too compact - and no watering schedule will compensate for that. This is also the time to check that the pot is suitable for the plant's size.
Drainage: what really works
Drainage is the subject of a widespread misconception: a layer of clay pebbles at the bottom of the pot is supposed to improve water drainage. In reality, in a pot with drainage holes, this layer does not drain anything at all - it even creates a saturated zone just above it and reduces the amount of soil available to the roots.
What really provides drainage is a drainage hole and an airy growing medium. Nothing else. If your pot has drainage holes and your mix is suitable, you do not need any layer at the bottom.
💡 When clay pebbles are genuinely useful
In a pot without drainage holes: a thin layer of pebbles raises the nursery pot and keeps it from sitting in the water that drains away. That is where they are useful - and it is their only real use.
That leaves decorative pots without drainage holes, which we love for their appearance. The safest solution is to keep the plant in its pot with drainage holes and slide it into the decorative pot, taking it out for watering if necessary. Planting directly in a sealed container means watering blindly, without ever knowing what accumulates at the bottom.
Finally, substrate wears out: it compacts, becomes depleted, and accumulates salts. After two years, even when well maintained, it needs to be replaced — that is precisely the purpose of repotting, which remains the most effective way to revive a stagnant plant.
Verdeia — Pots and decorative pots
The right container for the right mix
Pots with drainage holes, ceramic decorative pots, baskets made from natural fibers: find the container that lets the roots breathe without sacrificing style.
Frequently asked questions
For most foliage plants, yes, provided you add 20 to 30% perlite. Cacti, orchids, and carnivorous plants require a specific mix.
No: in a pot with drainage holes, they do not improve drainage. They are only useful at the bottom of an unperforated decorative pot to raise the pot.
No: it compacts, becomes water-repellent after a few waterings, and brings unwanted larvae and seeds into the home.
It creates air pockets between the particles without retaining the water, preventing the substrate from compacting and the roots from suffocating.
About every two years: beyond that, the substrate becomes compacted, depleted, and loaded with salts, even with good care.
Well supported
Plants that get off to a good start
Our plants arrive in fresh substrate suited to their family: for the first few months, they need nothing more than a good spot.
