Build Your Own Soil Mix: 3 Recipes That Actually Work
Store-bought potting soil works fine for some plants, but many houseplants do better in a custom mix. Here are three recipes that cover most indoor plant needs.
Why Not Just Use Potting Soil from the Bag?
You can. For a lot of plants, bagged potting soil works fine right out of the bag. Pothos, Monsteras, most foliage tropicals - they’ll be okay.
The problem is that standard potting soil holds a lot of water. That’s intentional - it was designed to stay moist longer, which is convenient for gardens but can be a problem indoors. Without the same airflow, temperature swings, and drying conditions as an outdoor garden, that moisture stays around longer. For plants that want their roots to breathe between waterings, you end up with perpetually wet soil and eventual root rot.
Mixing your own soil takes 10 minutes, costs less than buying specialty mixes, and lets you dial in exactly what a plant needs.
What the Ingredients Do
Before the recipes, here’s what each component brings to the mix.
Potting soil is the base - it provides nutrients, structure, and water retention. Any standard indoor potting mix works. Avoid ones with added fertilizer beads if you plan to fertilize yourself, since doubled-up fertilizer will burn roots.
Perlite is those little white foam-looking pellets you see in potting soil. It’s actually volcanic glass, heat-expanded into a lightweight, porous structure. Perlite improves drainage and keeps air pockets between soil particles, which roots need. It doesn’t hold nutrients or break down over time. More perlite = faster drainage and drying.
Orchid bark is chunky bark pieces, usually Douglas fir or pine. It creates significant airflow around roots and slows compaction. It holds some moisture while still allowing roots to breathe. Essential for aroids that have thicker aerial-root systems. Breaks down over a few years and needs replacing eventually.
Coarse sand is different from beach sand or play sand - you want horticultural or construction sand with visibly coarse particles. It improves drainage and adds weight (useful for top-heavy plants). Fine sand actually makes drainage worse by filling in soil pores.
Coco coir is the fibrous material from coconut husks. It improves water retention in a more balanced way than peat - it stays moist but also stays airy and doesn’t compact as badly. Renewable and pH-neutral. Good for plants that want consistent moisture without sitting in muck.
Recipe 1: Aroid Mix
For
Monstera, Philodendron, Pothos, Scindapsus, Alocasia, Colocasia, Caladium, Rhaphidophora
Mix
Equal parts potting soil, perlite, and orchid bark (1:1:1 by volume)
This is the workhorse mix. Aroids evolved in humid tropical forests where they grow in leaf litter and decaying wood - lots of organic matter, but also lots of airflow through the root zone. This mix mimics that: some moisture retention from the soil, excellent drainage from the perlite, and chunky air pockets from the bark.
Mix it by volume, not weight. A cup of potting soil, a cup of perlite, a cup of bark. Scale up as needed.
If you’re growing a particularly moisture-loving aroid (Caladium, some Alocasias), add a small amount of coco coir to the mix - maybe a quarter part. If you want faster drying for something like a Hoya, add more perlite or reduce the soil.
Recipe 2: Succulent and Cactus Mix
For
Echeveria, Haworthia, Sedum, Sempervivum, most cacti, Lithops, Agave
Mix
Equal parts potting soil, coarse sand, and perlite (1:1:1 by volume)
Succulents and cacti store water in their leaves and stems. Their roots need to dry out completely between waterings - sitting in moisture is one of the fastest ways to kill them. This mix drains almost immediately and dries out quickly.
A couple of notes: use coarse horticultural sand, not fine play sand. Fine sand clogs the mix. And don’t use a standard “Miracle-Gro” style potting soil with moisture-retaining additives - look for a basic, straightforward potting mix with no water-retaining crystals or gels.
You can also buy premade cactus/succulent mixes, but most are still too moisture-retentive. Cutting a store-bought cactus mix 50/50 with perlite or coarse sand is a quick fix that works well.
Recipe 3: Tropical Mix
For
Ferns, Calathea, Maranta, Stromanthe, Spathiphyllum, Fittonia, most moisture-preferring tropicals
Mix
2 parts potting soil, 1 part coco coir, 1 part perlite (2:1:1 by volume)
These plants want consistently moist but never waterlogged conditions. The higher soil ratio retains more moisture, the coco coir evens out the moisture distribution and prevents compaction, and the perlite keeps the mix from becoming dense and soggy.
This mix dries out slower than the aroid mix - which is the point. You’re still getting drainage and airflow, just with longer moisture retention to support plants that wilt if they get too dry.
Where to Buy Ingredients
Potting soil: any garden center, hardware store, or big-box store. Nothing fancy needed.
Perlite: almost always at garden centers in large bags. Also hardware stores with garden sections. Online if you can’t find it locally, though shipping big bags of perlite isn’t thrilling due to the weight.
Orchid bark: specialty garden centers, orchid suppliers, Amazon. Sometimes labeled as “orchid potting mix” or “pine bark fines.” Look for coarser chunks for aroids rather than fine-ground bark.
Coarse sand: hardware stores (sold as “coarse sand” or “horticultural sand”). Some garden centers. Avoid bagged play sand from home improvement stores - the texture is wrong.
Coco coir: garden centers and hydroponics shops. Often sold as compressed bricks that expand in water. A single brick makes a large amount of material. Store the extra dry.
If you’re in a major city, specialty houseplant shops often sell pre-mixed versions of these recipes, sometimes by weight. Convenient, but you’re paying a premium.
Mixing and Storing
Mix dry, before adding any water. Use a large bucket or container. For small quantities, old yogurt containers or quart-size pots work as measuring cups. For larger batches, an 8-gallon bucket with a single-line marked at each division lets you batch it efficiently.
Mix enough for one potting session or a bit extra. Don’t mix water into the stored soil.
Store leftover dry mix in a sealed container or bag. Dry ingredients stay good for at least a year. Organic materials like bark will break down slowly over time if stored wet, so keep it dry.
Label your containers if you’re storing multiple mixes. Perlite and coarse sand look similar after a few weeks and you don’t want to swap them in a recipe.
When the Soil Mix Matters Most
A good soil mix matters most for two groups of plants: the ones that are very particular about drainage (succulents, cacti, some orchids) and the ones you’re prone to overwatering. For the forgiving middle ground - most common tropical houseplants - a good standard potting mix is usually fine.
If your plant keeps getting root rot despite careful watering, the soil is probably the culprit. Switch to a more aerated mix. If your succulent is dying no matter what, the soil is almost certainly holding too much water.
The goal is a mix that matches the plant’s natural habitat. A desert cactus wants to dry out completely. A rainforest fern wants consistent moisture. Matching the mix to the plant removes a lot of guesswork from watering.