Potting Mix & Recipe by Volume

A good container mix balances three things: water retention from cocopeat or peat, nutrition from compost, and drainage and aeration from perlite, vermiculite or coarse sand. Garden soil alone compacts in a pot and suffocates roots, so a purpose-built mix of these components by volume gives roots air, moisture and food at once.

You set each component as a number of volume parts, and the tool splits the total volume by those parts: each component volume = total × (its parts ÷ total parts). A 2:1:1 cocopeat:compost:perlite mix of 40 litres gives 20 L cocopeat, 10 L compost and 10 L perlite — and the matching percentages.

Either enter a total volume in litres directly, or enter the number of pots and the volume of one pot and the tool multiplies them: total = pots × pot volume. So 20 pots at 5 L each need 100 L of mix, which it then splits into each ingredient by your parts.

A balanced all-round mix is roughly 2 parts cocopeat (or peat), 1 part compost and 1 part perlite — about 50% retention, 25% nutrition, 25% drainage. Tweak from there: more compost for hungry leafy crops, more perlite or sand for succulents and cacti that hate wet feet.

Match the mix to the plant. Succulents, cacti and herbs want extra drainage — push perlite or sand higher and cocopeat lower. Leafy and fruiting crops are hungrier — raise the compost share. Seedlings prefer a fine, low-nutrient mix, so go lighter on compost and finer on the components.

Cocopeat (or peat) holds water and keeps the mix from drying out. Compost supplies nutrients and beneficial biology. Perlite and coarse sand create air pockets and let excess water drain; vermiculite holds both water and nutrients. Blending them by volume gives the moisture-air balance a single material can't.

Potting components have very different densities — perlite is feather-light, compost is heavy — so weighing them gives misleading ratios. Container mixes are always built by volume (parts or litres) because that's what fills the pot and sets the air-to-water balance the roots actually experience.

Yes, with refreshing. Used mix loses structure and nutrients, so blend in fresh compost for feeding and fresh perlite or cocopeat to restore drainage and water-holding. Remove old roots and, if disease was present, sterilise or discard it. Treat the tool's recipe as the target your refreshed mix should hit.

They're accurate by volume for the parts you set, but real materials settle and compress, so mixed and watered volume is usually a little less than the loose components. Mix a touch extra, water it in, and top up pots after settling. The recipe gets you the right ratio and a close total.

Yes — use any components and any number of parts, for pots, grow bags, trays or raised beds, in litres or via pots × pot size. The volume-parts math is universal, so you can recreate a favourite recipe or design a new one and scale it to exactly the volume you need.