The material that your plants grow in is called the “growing medium or media” never dirt. Dozens of different ingredients are used in varying combinations to create homemade or commercial growing media. By understanding the functions of growing media, you can evaluate the qualities of individual types and select which ones might work best for your container garden. The choice is very important because your plants are dependent on a relatively small volume of growing medium. Unlike their cousins growing in garden soil, containerized plant roots cannot grow around obstacles or mine the soil far and wide for nutrients and water.
- Growing medium has three main functions- 1) supply roots with nutrients, air, and water, 2) allow for maximum root growth, and 3) physically support the plant.
- Roots grow in the spaces between individual particles of soil. Air and water also travel through these pore spaces. Water is the medium that carries nutrients that plants need to fuel their growth, and the air is needed for root growth and the health of soil microorganisms that help supply plants with nutrients.
- Irrigation water moves through the pore spaces, pushing out the air. If excess water cannot drain away, fresh air cannot enter and roots will suffocate.
- Select light and fluffy growing media for good aeration and root growth.