Potting Soil Recipe for Container Gardening

Basic Recipe Ingredients

• The basic ingredients for potted plant soil are equal portions of sand, soil and organic matter. The sand, referred to as builder's sand, is masonry grade and more coarse than play sand. Play sand does not let water drain as well as builder's sand. The soil you choose can be topsoil or a formulated mix for houseplants and container gardens. Conventional garden soil is heavy and compacts when used in containers. When building your basic planting soil, you have a wide selection of organic matter from which to choose: peat moss, coir, and pine bark. These materials help retain moisture and oxygen in soil. The compost adds nutrients for the growing plants.

Perennials and Succulents Recipe

• Most perennials and succulents need less moisture than annuals and other plants. Modify the basic mix so water drains more freely through the container. Add more coarse material, perlite, so the ratio is two parts potting soil and one part each of builder's sand, perlite and peat moss. You can substitute well-rotted compost for the peat moss as long as the compost has decayed completely. Another additive that benefits succulents is calcined clay. This mineral aids in soil aeration. Moisten the soil mix before filling the container so no dry spots are in the mix when you plant.

Foliage Plant Recipe

• Add one more portion of soil to the basic recipe when you will grow foliage plants. Those kinds of plants generally prefer a rich, loamy soil that retains more moisture than other mixes. If you prefer, add 1/2 portion of well-rotted compost and 1/2 portion of soil. The end recipe is one part each of builder's sand and organic matter, with two parts soil or 1 1/2 parts soil and 1/2 part compost. The compost must be well-rotted because during the composting process, chemicals such as ammonia and salt are released, which can burn plant roots.

Fertilizers

• A problem that faces container gardens is a lack of nutrients during the growing season. If you use well-rotted compost in your soil mix, the nutrients are present during the start of the season but leach out the remainder of the season. Therefore, a timed-release fertilizer can be added to the soil mix so the plants have enough nutrition throughout the growing season. A timed-release fertilizer sends out nutrients when the temperature is warm and plants are growing. Follow the fertilizer package's directions when mixing the fertilizer into the soil mix. Generally, a ratio of 3 tablespoons of fertilizer to a 2-by-2-foot area of soil mix works well.