Growing Media:

Growing media consist of mixtures of components that provide water, air, nutrients and support to plants. The media provide plant support, while the nutrients are provided by added fertilizers. Water and air are provided in the pore spaces in the media. Four main factors affect air and water status in containers: the media components and ratios, height of the media in the container, media handling and watering practices.

Growing media for use in container production in greenhouses contain a variety of soilless ingredients such as peat moss, vermiculite, perlite, shredded coconut husks (coir), composted bark or other composted materials. Growing media are designed to achieve high porosity and water retention while providing adequate aeration.

Another factor relating media to air/water relations in the root zone is the size of the growing container. With media in containers, the amount of air and water held in a given growing medium is a function of the height of the column of media. The taller the column of medium, the smaller the ratio of water-filled pore spaces will be to air-filled spaces.