Soil-less potting mixes are typically used for one thing – growing plants in pots. Nature never intended plants to grow in pots. Container gardening is a human invention. Growing plants in containers cramps roots and limits the plants' food and water supply. Soil-less planting mixes ensure potted plants get the best growing environment possible.
Ordinary garden soil is generally made up of, well, dirt. Dirt contains loam, clay, silt, stones, organic matter and a multitude of organisms (good and bad), soil-borne diseases, weed-seeds and even bits of trash. The effects these naturally occurring elements have are aggravated in the unnatural confines of a pot, making life for potted plants a struggle. In addition, when plain garden soil is used in pots, it gets hard or compacted over time and both water and air find it difficult to get to the plant roots.
Wheeler Zamaroni’s high quality soil-less potting mixes are made up of varying proportions of organic matter and other naturally-occurring materials. (Mixtures are specific to their intended use.) The materials are pre-measured to give the perfect levels of aeration, drainage and moisture-retention for maximum plant performance. Soil-less mixes intended for planting are also typically sterilized to remove harmful soil-borne bacteria, pests and weed seeds before they are mixed in with other ingredients.