Types of Hydroponic Growning Mediums

Hydroponics is an agricultural method used for growing plants without the use of soil. The plants, however, still require a habitat that provides stability, allowing its roots to reach the source of nutrients while the plant continues to grow. Hydroponic growing mediums consist of such materials as coconut fiber, rockwool, perlite and sand. These materials are inert, that is, they do not provide nutritional elements to the plant.

Coconut Fiber

Coconut husks are fibrous and contain little-to-no nutrients. They have no value within the coconut producing industry. The shredded husks, however, are an organic material that's appropriate for a growing medium in hydroponics systems. Coconut fiber may be compressed to form cubes or blocks suitable for seeding. The coconut fiber retains the nutrient-rich solution essential to sprouting. Place the cube or block with the anchored seedlings in the hydroponics system.

Rockwool

Rockwool is compressed volcanic rock and limestone. Available in cube or block form, it is used in much the same way as coconut fiber. However, rockwool may affect the pH balance of the nutrient solution used in a hydroponics system. With a pH of 7.8, it may raise the balance of the solution. Most plants prefer a lower pH, between 4.5 and 6. Counter this with the use of a pH additive.

Perlite and Sand

Perlite and sand are appropriate mediums when using a basic wick system or ebb-and-flow system. Both of these systems use perlite or sand to make the nutrient solution available to the plant. The seeds root in the medium; the plant remains in the medium. The perlite or sand is regularly flooded with the nutrient solution and then allowed to dry out. Use these mediums for plants that are adapted to slow evaporation or slow-draining soils. Both perlite and sand hold moisture, and the solution doesn't flow through the medium, but rather evaporates from it. Use this medium for herbs such as spicy globe basil or oregano.

Soilless Mixes

These mixes resemble potting mixes used for container gardening. The mixes do not contain nutrient-rich soil, but rather a combination of sphagnum moss or peat moss, sand and/or perlite, composted bark and coconut fibers. The soilless mix in hydroponics may be used in the same way as sand or perlite in the wick system or ebb-and-flow system. The advantage of soilless mix is it does not hold moisture as long as the other two mediums, allowing for a more diverse range of plants.