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Houseplant soil ingredients explained
Every good mix balances three jobs: holding water, letting air in and giving roots structure. Here is what each common ingredient contributes.
Drainage and air
Perlite
Expanded volcanic glass. Very light, adds air pockets and stops compaction. Can float to the top when watering.
Most useful for: Pothos, peace lily, monstera
Drainage and weight
Pumice
Porous volcanic rock that holds a little water inside and never breaks down. Heavier than perlite, so it stays put.
Most useful for: Succulents, ZZ plant
Structure
Orchid bark
Chunky pine or fir bark that creates large air gaps, like a forest floor. Breaks down slowly over 2 to 3 years.
Most useful for: Monstera, fiddle leaf fig, ZZ
Moisture
Coco coir
Coconut husk fibre. Holds water evenly, rewets easily and is a renewable alternative to peat. pH about 5.5 to 6.8.
Most useful for: Calathea, peace lily, pothos
Moisture
Peat moss
The base of most bagged mixes. Holds lots of water but turns hydrophobic when bone dry. Acidic, around pH 3.5 to 4.5 before liming.
Most useful for: Base mix for most tropicals
Optional additive
Horticultural charcoal
Adds some structure. Claims that it purifies soil are weak; use it sparingly, under about 10% of the mix.
Most useful for: Terrariums, optional in aroid mixes
Drainage and weight
Coarse sand or grit
Use coarse horticultural sand or grit, never fine play sand, which fills air gaps and makes soil denser.
Most useful for: Snake plant, succulents
Guides
Ingredients
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Understand the differences between cactus soil vs potting soil. Learn when to use each, how they drain, and how to convert regular soil into a desert mix.
Soil problems
How to Fix Compacted Soil and Hydrophobic Potting Mix
Learn how to fix compacted soil and revive hydrophobic potting mix. Follow our guide on aeration, soil softening, and bottom-watering to save your plants.
Ingredients
Perlite vs Pumice: Which Is Better for Houseplant Soil?
Compare perlite vs pumice for houseplant soil. Learn the pros, cons, weight, and best uses for each drainage amendment to help you choose the right one for your pots.