Hydroponic Growing Medium Mixture. Hydroponic growing media is simply a soil-less material that is generally porous so it can hold the moisture and oxygen that the root system requires to grow. Non porous materials can be used as well, but watering cycles would need to be more frequent so the roots don't dry out between watering's.
Creating a soilless mix containing perlite and/or vermiculite are a common grow medium used in hydroponics, and are often blended with coconut fiber to form a hydroponic mix. The growing medium won't be able to grow anything on its own. A surface, which is moist and exposed to light, can be the ideal conditions for algae growth.
NOTE: The following documentary depicts legal cannabis horticulture within the state of California under the Adult Use of Marijuana Act.
Unfortunately, there is no perfect medium; different types of hydroponic systems work better with certain growing mediums.
DIY Hydroponic Growing Systems. • Netted Cup - You can either purchase netted cups, or make your own homemade ones out of plastic cups that are Medium - You will need a small amount of growing medium, enough to fill the plastic cup, most commonly expanded clay, or a perlite/vermiculite mixture. Plants grown in colder climates will thrive in cooler water, while plants grown in warmer regions prefer warmer water. The aeration breaks up the matter and helps nutrients spread through the liquid mixture.