Potting Mix for Pots: The Soil, Cocopeat and Compost Ratio
A good potting mix for pots is simple: for herbs and vegetables, mix roughly equal parts garden soil, cocopeat and compost by volume, and add a little sand or perlite if your soil is heavy clay. Garden soil alone packs down hard in a pot and drowns roots. Succulents like aloe want a grittier mix, and seeds want a finer, lighter one. Below are three recipes, what each ingredient does, and how to prepare a cocopeat brick properly.
The short version
- Herbs and vegetables: 1 part soil, 1 part cocopeat, 1 part compost
- Aloe and succulents: 1 part soil, 1 part coarse sand, a little compost
- Seed sowing: 1 part cocopeat, 1 part fine sieved compost
- Measure by volume: use the same bucket or tin for every part
- Cocopeat brick: soak, then rinse once before use
- Refresh: top up compost each season, change the mix every year or two
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Can you use garden soil in pots?
On its own, usually not well. In the ground, soil drains down into more soil and worms keep it open. In a pot, the same soil gets watered daily, packs down into a hard cake, and holds water at the bottom with no air for the roots. Roots need air as much as water. That is why a plant from a lovely garden bed often yellows and rots within weeks of being potted in that same soil.
Garden soil is still useful as one part of the mix. It adds weight so pots don’t tip over, and it holds minerals. The trick is to lighten it.
Three potting mix recipes, by volume
Use one bucket, mug or ghee tin as your measure for every part. These are starting points, not laboratory formulas; adjust after watching how fast your pots dry.
| Mix for | Garden soil | Cocopeat | Compost | Sand or perlite |
|---|---|---|---|---|
| Herbs and vegetables | 1 part | 1 part | 1 part | Optional, a handful per bucket if soil is heavy clay |
| Aloe, succulents, cactus | 1 part | None or a little | A handful | 1 part coarse sand |
| Seed sowing trays | None | 1 part | 1 part, sieved fine | None |
For a single 30 cm (12 inch) pot, which holds roughly 12 to 15 litres, one 5 litre bucket of each part for the herb mix is about right with a little left over.
What does each part of the mix actually do?
- Garden soil: weight, minerals and some water holding. Take it from a clean garden bed, never a construction site or roadside, where it may be rubble or carry oil and paint.
- Cocopeat (coir): the fibre from coconut husks. It holds water like a sponge but stays airy, so it stops the soil packing hard. It has almost no food value of its own.
- Compost: the food. It feeds roots slowly and helps the mix hold together. Homemade is ideal; see our bucket and matka compost guide or the vermicompost guide for kenchua khad.
- Coarse sand or perlite: drainage. Use coarse river sand, not fine plaster sand, which clogs gaps instead of opening them. Perlite is the white, light granules sold at nurseries.
How to use a cocopeat block
Cocopeat is usually sold as a hard compressed brick at nurseries, garden shops and online stores in Pakistan and India. It expands many times its size once wet, so start with a big bucket.
- Put the brick in a large bucket or tub.
- Pour water over it slowly, a few litres at a time, and wait 20 to 30 minutes.
- Break it apart with your hands as it softens, adding water until it is fluffy and evenly damp.
- Rinse once: fill with fresh water, stir, and pour off the brown water through a cloth or your fingers.
- Squeeze a handful. It should feel like a wrung out sponge, not dripping.
The rinse most people skip
Rehydrate a cocopeat brick in a bucket and rinse it once before mixing. Coir is often salty from processing, especially cheaper bricks, and that salt can scorch the roots of seedlings and tender herbs. Many packs are labelled “washed” or “low EC”; those are worth choosing, but one quick rinse at home costs nothing and removes the doubt.
How to make potting soil at home, step by step
- Sieve the garden soil through a wire mesh or old basket to remove stones, roots and plastic.
- Prepare the cocopeat as above.
- Measure each part into a tub or onto an old plastic sheet.
- Mix with gloved hands until the colour is even.
- Dampen it lightly. It should hold together when squeezed and crumble when poked.
- Fill pots that have drainage holes, firming gently but not pressing hard. Leave 2 to 3 cm at the top for watering.
Skip the old advice to put a layer of pebbles at the bottom of the pot. It actually raises the wet zone inside the pot rather than helping drainage. A clear drainage hole does the job.
Do you need to sterilise potting soil?
For big pots of herbs, usually not. For seed trays, where damping off fungus can topple seedlings, a simple shortcut helps: spread the damp mix thinly on a tray in strong summer sun for a few days, turning it once or twice, or use fresh cocopeat and sieved compost, which are relatively clean. Avoid heating soil in the kitchen oven; it smells bad and can release fumes from any plastic bits.
Did you know? Coir was once mostly a waste product of the coconut industry; using it in pots is one of the oldest zero waste swaps in gardening.
Myth: more compost is always better
A pot filled with pure compost tends to hold too much water, shrink as it breaks down, and can be too rich for herbs, which give less aroma when overfed. About a third is plenty for most edible plants. Feed later with a top dressing instead.
How often should you refresh potting mix?
Each growing season, scrape off the top 2 to 3 cm and replace it with compost. Every year or two, or whenever water sits on top instead of soaking in, tip the plant out, shake off the old mix and repot. Old mix is not waste: add it to your compost bin or mix it with fresh compost for the next batch. The balcony herb garden guide has the pot sizes for common herbs.
Safe handling and heavy pots
Wear gloves and avoid breathing dust when mixing dry soil, compost or perlite; dampen it first to keep dust down, and wash hands afterwards. Keep cuts covered when handling soil. Don’t add chemical fertilizers or pesticides to pots that children and pets can reach. Remember that a pot of wet mix is very heavy: on balconies and roofs, place big pots near walls and beams, never on a cracked slab or hanging over a railing.
Potting mix questions people ask
What is the best soil mix for potted plants?
For most herbs and vegetables, equal parts garden soil, cocopeat and compost by volume. Add some coarse sand if your soil is heavy clay, and use a grittier mix for aloe and succulents.
What is a good cocopeat, soil and compost ratio?
One part each is a reliable starting point. If pots dry out too fast, add a little more cocopeat; if they stay soggy, add sand and reduce cocopeat.
Can I use garden soil in pots?
Only as part of a mix. Alone it packs down and holds water at the bottom, starving roots of air. Lighten it with cocopeat and compost.
How do I make potting soil at home?
Sieve garden soil, soak and rinse a cocopeat brick, then mix equal volumes of soil, cocopeat and compost. Dampen lightly and fill pots that have drainage holes.
What soil is best for herbs in pots?
A light, well drained mix of soil, cocopeat and compost. Herbs prefer moderate feeding; too much compost gives soft leaves with less smell.
How do I use a cocopeat block?
Soak it in a large bucket, add water slowly, break it up as it softens, then rinse once to remove salts. Squeeze until it feels like a damp sponge before mixing.
Can I grow plants in only cocopeat?
Seeds and seedlings, yes, briefly. For longer growth you need compost or fertilizer, because cocopeat itself carries almost no plant food.
Should I put stones at the bottom of a pot?
No. A gravel layer raises the soggy zone inside the pot. A clear drainage hole and a well drained mix work better.
How often should I change potting soil?
Top dress with compost each season and fully repot every year or two, or sooner if water sits on the surface and won’t soak in.
More pot growing and composting guides live in Zero-Waste Kitchen.