Common Additives To Aerate Soil In Potted Plants Perlite. The lightweight, airy volcanic rock helps aerate the soil and improve drainage. Styrofoam is often substituted for perlite in potting mixes, but it does not act as an aerator. Coarse sand. By breaking up denser soils, large particles of sand help improve drainage. Vermiculite. A mineral … Continue reading Compacted Soil in Houseplants: Methods of Aerating to Fix it