Homemade Soil Amendments for Indoor Plants

Nutrients Plants Need

• Nitrogen, phosphorus and potassium are the nutrients plants need from the soil in the highest quantities. They receive hydrogen, oxygen and carbon from air and water. Soil for potted indoor plants must also supply sulfur, calcium and magnesium as secondary nutrients. The elements needed in small amounts include zinc, iron, copper, manganese, boron, molybdenum and chlorine. Ordinary garden soil with adequate organic matter content easily provides the 13 essential nutrients but houseplant soil leaches nutrients out more quickly than outdoor soil.

Homemade Compost Amendment

• The surest way to amend soil and improve plant growth is the regular addition of composted organic matter. Homemade compost can be spread around the topsoil of a potted plant, or diluted in water to use as a fertilizer tea. The nitrogen in homemade compost promotes strong leaf growth and dark green color. Its potassium encourages plant vigor and helps resist disease. Mature compost is dark brown, crumbly and has no odor, so it is easy to use indoors. Add a tablespoon of finished compost to the watering can each time the plants are watered to provide a constant slow-release soil amendment.

Epsom Salts

• Epsom salts is a homemade amendment that adds magnesium and sulfur to the soil. The addition of magnesium and sulfur improves chlorophyll production and the absorption of phosphorus and nitrogen. Magnesium also helps build strong cell walls. Add 2 tablespoons Epsom salt per gallon of water and apply monthly to indoor plants. Reduce the amount to 1 tablespoon for plants that are watered more frequently. To prevent the buildup of salts over time, allow some liquid to flow from the bottom of the pot each time it is watered.

Eggshells and Fish Tank Water

• Eggshells are a good soil amendment substitute for the calcium-rich bone meal that is often a part of commercially available soil amendments. Collect cleaned eggshells covered in water in a jar with the lid loosely attached. Add additional eggshells as they are acquired and leave the jar to soak for one month. Use one cup of the liquid for each gallon of water for the indoor plants. Use fish tank water as a soil amendment and plant fertilizer whenever the tank is being cleaned. Fish waste is also effective as a foliar spray.