Choosing a good house plant soil is vital to ensuring the growth and health of your indoor plants. While common garden soil is sufficient for many outdoor plants, potted plants require additional support and nutrients to help them flourish in an indoor setting. Most types of plants do well in a basic house plant soil, though some plants, like orchids, may grow better in a specialized soil.
If you’re purchasing a house plant soil pre made, look for an indication on the bag that the soil is formulated for indoor plants. Indoor soil preparations typically include some garden soil to provide a base for the plant. They also contain peat moss, which makes the soil lighter and helps absorb water. Perlite is also common in house plant soil because it helps space the soil to help the roots grow and prevent water-logging. Specialty soils may use shredded bark or charcoal in place of the traditional substances to provide a supportive soil for certain plants, such as orchids.
Most commercial varieties of house plant soil are sterile. These mixes help prevent disease and weeds. Unsterile mixes are also available, but are less desirable, particularly for starting house plants from seedlings when they are most susceptible to disease. Some house plants, such as azaleas, require an acidic soil, so check the package for the pH. Soil that has more peat moss is more acidic than typical potting soil.
Some indoor gardeners prefer to mix their own soil. This requires sterilization of garden soil in a sealed pan in the oven. Heating the soil for 30 minutes at a temperature of 200° F (about 93° C) is usually sufficient. To be considered sterile, the dirt should register a temperature of at least 150° F (about 65° C). The soil is then mixed with equal parts of perlite and potting soil for most plants. Sand can also be added to increase drainage for plants that do not need held moisture, such as cacti.
Most house plants need to be repotted every year or two to remain healthy. House plant soil breaks down over time, which restricts drainage and stifles the roots. Salts and other particles from fertilizer can also build up in the soil over time and suffocate the roots or prevent needed nutrients from reaching the plant. Flushing the soil regularly can help it last longer, and potting mixes made yourself will typically last longer than premixed soil.
