Vermiculite is a lightweight, porous mineral commonly used in potting mixes and seed-starting mediums for its excellent water retention and aeration properties. When heated, vermiculite expands into small, sponge-like particles that help soil retain moisture while also providing good drainage. Vermiculite is often used in combination with other growing media, such as peat or perlite, to create an ideal environment for seed germination and root development.
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