Potting mix
/ˈpɑtɪŋ mɪks/
Definition
Potting mix is a container-growing substrate, or rooting medium, formulated for plants grown in pots rather than in the ground. It usually contains ingredients such as peat moss, coir, bark, perlite, or composted materials, blended to balance drainage, air space around roots, moisture retention, and support. Unlike garden soil, it is typically lighter, more porous, and less likely to compact in a container.
Practical Relevance
- Root-zone air and water balance: Potting mix controls how quickly roots receive oxygen and how long moisture stays available. A coarse blend drains faster, while finer particles hold more water and can keep roots wetter for longer.
- Nutrient behavior in containers: In pots, roots depend on potting mix for water and dissolved nutrients between feedings. Some blends include compost or slow-release fertilizer, while others are intentionally low in nutrients for tighter feeding control.
- Matching plants to the blend: Plant groups grow better when the texture suits their roots and moisture needs. Orchids need very airy material, while seed-starting and many tropical houseplants do better in finer, more even blends.
Related Terms
Orchid bark
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Perlite
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Vermiculite
Vermiculite is a lightweight mineral material used in potting mixes and seed-starting media. It is made by heating a…
Self-watering pot
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Watering
Watering is the horticultural practice of applying water to soil or growing media around plants, or less often directly…