Basic Indoor hydroponics Gardening Guide – Hydroponics Growing Mediums

Basic Indoor hydroponics Gardening Guide – Hydroponics Growing Mediums

These are the materials that mimic the soil in everyday gardens. It serves as a support system for your hydroponic indoor garden. They function mainly for anchoring the roots and a reservoir for water and nutrient solutions. Special attention is also placed on aeration or proper plant respiration and drainage. A balance must be kept between keeping the plant nourished and over saturating the roots.

Types of Growing Mediums

Choice of a specific growing medium mainly depends on the type of growing system to be used. Certain systems have no mediums used because plant growth is best when roots are suspended in air or water. Improvement made with newer growing medium mixtures has been introduced for optimum plant growth in certain systems. Ideally, an equal mixture of water and air is advised making it available for the roots to utilize at all times. Water by gravity always moves downward through coarse mediums only to be deposited in the bottom of the container. This is eliminated with the use of a hydroponic system as water is constantly circulated in the system. The only system that this would not work would be the Ebb and Flow Systems.

Clay Pebbles

Recyclables, it can be constantly reused indefinitely reducing upkeep costs for your indoor garden. Size of the pot is one limiting factor as they do not possess good nutrient lifting ability, but effectiveness is enhanced in smaller pots and containers. Another advantage would be their neutral pH and they don’t retain nutrients. Ventilation and aeration are also maximized because of the spaces created between pebbles.


Clay pebbles are usually used together with net pots in drain and flood indoor hydroponic gardening systems. Water flow in roots is enhanced by their natural shapes and spaces hey create between them, therefore maximizing the absorption of nutrients. When using the Drip irrigation hydroponic system, use absorbent mediums to provide better retention and nutrient circulation.

Coconut Fiber


Shredded husks of coconuts as a growing medium has also been growing in popularity. Packaged in a variety of ways like blocks, pellets, cubes and shredded fiber it can be a good substitute for any type of growing medium. It is also commonly mixed with other growing media such as perlite or rockwool.

Why Use Coconut Fiber as a Growing Medium?

Coconut fiber is actually a waste product; its ability to be used for other useful means takes a great step towards recycling and environmental awareness. It is the first totally organic medium which could be utilized for indoor hydroponic gardening. It is superior to rockwool in water handling ability and oxygen capacity. Coconut fibers also possess root stimulating hormones and prevent root disease and fungus infection. In its natural state, coconut fibers provide a good and rich medium for the coconut when it lands in the ground.

Special attention should be given as to the quality of the coconut fiber to be purchased. Low grade quality is not well suited for gardening as they contain high sea salt content and fine grain texture.


Originally used as an additive to aide aeration and improve soil drainage, it has become one of the popular hydroponic growing mediums. Commonly used with a 50/50 mix with vermiculite, it is derived from volcanic glass with holes throughout produced by exposing it to high temperatures created by water bubbles.

Advantages of Growing with Perlite

Inexpensive and readily available is one of the causes of its popularity. Used in wick type hydroponic systems because of its aerate nature thereby giving a good wicking action.

Disadvantages of Growing with Perlite

Health hazards come with the use of perlite when inhaled, a mask is suggested when working with perlite as a growing medium. A high degree of care and maintenance is also required. Water retention is one of its weakness therefore constant watering is required.


Used in conjunction with another growing medium compliments the qualities of the other. A popular and common mix is that with perlite. In a 50/50 mix vermiculites property which is water retention (200 – 300% of its weight in water) complements perlites very porous quality and a balance is achieved.

Dangers of Using Vermiculite

Vermiculite can be a health hazard if not handled properly. Due to its nature of containing small amounts of asbestos, it can be very dangerous when inhaled. It easily dries on an individuals fingers when touched even when wet. It is not also practical to reuse because of the rinsing and drying required. Water retention is also a problem, because of its high water retention if not used in pair with another growing medium, root damage is likely and plant death are the result.


Rockwool specifically made for indoor hydroponic gardening systems. It has remained as one of the popular growing mediums. Transplanting plants when grow too big from their previous containers is also eliminated. When this happens the existing cube with the plant is merely placed on top of a larger cube and the roots would grow through both cubes. Water retention qualities of rockwool is 10 times greater that of water. Its porous nature makes it virtually impossible to over water. Recyclable, it can be used for the next crop by merely rinsing, making it economical and environment friendly.

Disadvantages of rockwool

A natural pH found in rockwool is one of its disadvantages, pre-treatment is required before it is used as a growing medium. Methods of lowering its alkaline content includes mixing it with a solution of pH down, trace mineral solutions and a 24 hour fish emulsion and is then rinsed thoroughly. Gloves should be used when handling rockwool because of skin irritation but is not when rockwool is wet.

Help your garden grow with these great items…

Related Gardens Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.