Compost.

Organic matter decomposed by microbes into a stable, humus-rich material; in the UK and Ireland the word also names bagged potting media.

What it means for your plants

Garden compost adds nutrients and biology to beds but is too fine, variable and pathogen-prone to use alone in pots; if used, keep it to about 10–20% of a container mix. UK multipurpose compost is a formulated potting medium, not decomposed garden waste.

Put it into practice

Choose a suitable houseplant potting mix, understand bag labels and ingredients, and avoid drainage mistakes without relying on a universal soil recipe.