There is no single best potting mix for every houseplant. A good mix holds enough water for the roots and keeps enough air around them. The right balance depends on the plant: a cactus, an orchid and a Boston fern want very different root zones.

Start with what the plant grows in by nature, then pick a mix built for that. This guide covers the main houseplant groups. For why mixes hold water and air the way they do, see soil science for houseplants. For compost and garden soil questions, see potting soil vs compost.

What every good indoor mix has in common

University of Maryland Extension says commercial soilless mixes typically contain sphagnum peat moss, perlite, vermiculite, composted bark, compost and coconut coir, plus small amounts of lime and fertilizer. Most have a pH of about 6.2.

Iowa State Extension describes quality potting media as roughly 85% pore space. That air space is what keeps container roots from suffocating after watering. The NC State Extension Gardener Handbook lists the qualities to look for: good drainage, aeration, water-holding capacity, light weight, some fertility and pasteurization.

Iowa State notes that most home gardeners use a pre-made all-purpose mix, with special mixes for orchids and succulents. That is a sound default. Adjust only when the plant group calls for it.

Plant type, mix and components at a glance

Plant typeWhat the mix should doTypical components (source)
General tropical foliage (pothos, peace lily, dracaena)Hold moisture, still drain freelyMore peat or coir, less coarse material (Illinois)
Aroids (monstera, philodendron, anthurium)Hold moisture with good aerationPeat, perlite and bark; 1:1:1 for anthurium (UF/IFAS)
Cacti and succulentsDrain fast, dry between wateringsExtra perlite, bark, grit or coarse sand (Illinois, NC State, RHS)
Epiphytic orchids (moth orchid)Very open, air around rootsBark-based orchid medium (NC State, Iowa State)
African violetsLight, fertile, drains quickly2–3 parts peat, 2 vermiculite, 1 perlite (NC State)
Ferns and moisture loversStay evenly moist, never soggyPeat or coir with vermiculite; less coarse material (Illinois, NC State)

General tropical foliage plants

Illinois Extension says tropical and foliage plants prefer mixes with more peat and less coarse material. These plants like moisture-retentive conditions. An all-purpose soilless mix usually fits this group without changes.

If you want to blend your own, Illinois gives a houseplant mix of one-third soil, one-third peat moss and one-third perlite or vermiculite. The soil must be sterilized. Never use garden soil straight from the ground.

Aroids: monstera, philodendron and anthurium

“Aroid mix” is a common search term, and the idea behind it has support. Many aroids climb trees in the wild, so their roots expect air as well as moisture. NC State describes Monstera deliciosa as starting life on the ground and turning epiphytic once it reaches a tree.

The published guidance we found comes from UF/IFAS commercial growing guides:

  • Anthurium: UF/IFAS lists a 1:1:1 mix of Canadian peat, perlite and bark for interiorscape anthurium production. It gives a target pH of 6.0 to 6.5.
  • Philodendron: UF/IFAS says sphagnum peat, pine bark, vermiculite or perlite can be combined, and the medium should have good moisture-holding capacity and aeration.
  • Monstera: we found no extension recipe written specifically for monstera. NC State advises watering thoroughly, then letting the top quarter to third of the mix dry.

So a simple aroid mix is equal parts peat (or coir), perlite and bark. That is the UF/IFAS anthurium recipe, not a tested monstera formula. Each part has a job. Peat or coir holds water. Perlite gives long-lasting air pockets. Bark adds structure and larger air spaces. If your mix stays wet for a long time, add more bark and perlite. If it dries out within a day or two, add more peat or coir.

See the monstera, philodendron and anthurium hubs for watering and light.

Cacti and succulents

These plants rot when roots sit wet. Illinois Extension recommends coarser mixes with more bark, perlite or sand for succulents. NC State’s handbook says that for plants preferring dry conditions, potting mix and sand should be no more than a third of the blend, with perlite added for air space.

NC State’s plant toolbox describes Mammillaria growing best in a well-drained cactus mix with added grit or coarse sand. The RHS also suggests adding grit or sharp sand where a plant needs extra drainage. Use coarse builder’s sand, never fine play sand, which Illinois warns against.

NC State adds that porous pots such as unglazed clay dry faster, which helps cacti and succulents. See the echeveria and jade plant hubs, or our guide to cactus types for indoors.

Orchids

Most orchids sold as houseplants are epiphytes. Their roots cling to bark and need air. NC State says moth orchids (Phalaenopsis) are grown in a bark-based medium that provides excellent drainage. Ordinary potting soil stays far too wet for them.

Iowa State notes that coarser orchid bark produces more air-filled pores, and that coarse chunk peat is also used for orchids. NC State warns that pure sphagnum moss can be difficult to rewet once dry. It recommends moving such plants into bark-based orchid medium. Repot about every two years, after flowering. More on the orchid hub.

African violets

African violets need a light, fertile mix that drains quickly. NC State recommends 2 or 3 parts sphagnum peat moss, 2 parts vermiculite and 1 part perlite. Add lime to balance the acidity of peat. Or use coir, which NC State says is more sustainable than peat and has a near-neutral pH.

Plant with the crown above the surface, and do not let water sit on top of the mix. Water from below to keep the leaves dry. See the African violet hub.

Ferns and other moisture lovers

NC State says Boston fern needs moist soil that should never dry out, with less water in winter. Pick a mix weighted towards peat or coir, the moisture-retentive end of Illinois’s guidance. Vermiculite helps too: Iowa State describes it as good for water and nutrient retention.

Moist does not mean waterlogged. The pot still needs a drainage hole. See the Boston fern hub.

What “organic” on the bag means

Peat, coir, bark and compost are all organic materials in the plain sense: they come from living things. So most potting mixes are largely organic matter already.

On a label, “organic” usually describes the additives. University of Maryland Extension says organic versions of soilless mixes omit chemical wetting agents and use organic instead of synthetic fertilizers. That can matter if you prefer organic inputs. It does not change how well the mix drains.

One practical effect: without a wetting agent, a dry mix can be harder to wet. Maryland says soilless mixes tend to repel water when dry. Work water in by hand until the mix is evenly damp before you pot.

Peat vs peat-free: coir, bark and compost

Peat holds water and nutrients well, which is why it became the standard base. But NC State’s handbook says peat is not a sustainable resource. The RHS explains that peatlands support unique wildlife, and that draining them for extraction releases carbon dioxide.

Peat-free mixes replace it with other materials. The RHS lists the main ones:

  • Coir: coconut husk fibre that holds water well. Iowa State says both coir and peat become hydrophobic if allowed to dry out.
  • Composted bark: usually pine bark, which adds air to a mix.
  • Wood fibre: treated wood chips, made looser or more fibrous depending on processing.
  • Green compost: composted garden waste, used as one ingredient.

The RHS says peat-free mixes need different handling, especially watering and feeding. Check the mix with a finger before watering, rather than going by habit. Watch for slower growth that could mean feeding needs to change.

Before you repot

  1. Match the mix to the plant group above.
  2. Pre-wet soilless mix until evenly damp, as Maryland advises.
  3. Use a pot with a drainage hole. NC State says drainage holes keep roots from standing in water and developing root rot.
  4. Check the bag for added fertilizer. Maryland says commercial mixes include a small amount, so you may not need to feed straight away.

Not sure it’s time? Check the signs your plant needs repotting first. Our potting soil vs compost guide covers pot size and planting depth. When feeding does start, the plant food guide explains how to choose a product.

References