Homemade Soil-Less Fertilizer Mix

Mineral Ingredients

• Mineral ingredients provide drainage for the plants in the pot. They also prevent the soil from compacting too quickly by providing aeration. Vermiculite, a type of mica, holds water and nutrients. Perlite, a volcanic mineral, provides aeration. Sand is sometimes used instead of perlite or vermiculite, though all it provides is some weight and aeration. Calcined clay is sometimes used instead of other mineral ingredients in succulent or cacti pots because of the excellent drainage it provides.

Organic Ingredients

• Compost resembles soil but it's actually the byproduct of decomposed vegetation or animal manure. It provides the main bulk of some potting mixes and is used as a soil replacer. Peat and sphagnum peat moss absorb water and can improve the moisture-holding capacity of some potting mixes. Peat is acidic, making it a good choice for plants that require a lower soil pH. Shredded bark, particularly from pine trees, is also used to add bulk and organic matter to soil-less potting mixes.

Fertilizers

• Except for compost, most soil-less ingredients provide few nutrients. Fertilizers mixed in with the potting mix supply the necessary nutrients for healthy plant growth. A general-purpose timed-release fertilizer added to the mix before you plant typically provides enough nutrition for the first two to three months after planting. Organic fertilizers, such as bone meal and blood meal, are another fertilizer option. Soluble fertilizers applied after planting replenish the nutrients as the plants use them.

Mixes

• The ingredients and the amount of each used depend on the type of plants growing in the container. A general-purpose mixture consists of equal parts compost, peat moss and vermiculite or perlite. A mixture for desert plants, such as cacti, contains two parts sand to one part compost or peat moss. Equal parts peat and vermiculite provide a sterile medium for starting seeds. The vermiculite prevents the peat from crusting, which allows the seedlings to push through easily.