Gardeners experience proves that the mixture of vermiculite, perlite, and organic potting soil (loose 100% organic soil mixture is also suitable) in equal proportions is the best for the successful . Such mixture offers the perfect upward capillary action of water and supply of CO2 and oxygen. Organic soil in the upper medium layer provokes microbial action.

Some growers practice mixing organic nutrients (e.g. worm castings) into the upper medium part. Others just distribute them on the surface of the grow medium and then spray them with water. Another way is to mix nutrients with half a cup of water and pour onto the top of the medium. Any of these methods ensure proper nutrients entrance into the soil mixture and good absorption by the plants primary roots.

The upper layer of the medium is also called “soil alternative”, as it is the place where the nutrients are supplied to. It is treated as a standard soil container. To improve the capillary action of the water delivered by the lava rock at the bottom, it is recommended to spray the soil alternative once or twice a day with water.

Creating your using hydroponics system pay special attention to the level of the pumped water, this must not moisten the upper part of the medium. If this happens, the nutrients, delivered to this soil part of the growing medium, will be washed out into the water reservoir, becoming unavailable for the upper part of the plants root system.

The usual watering cycle takes about half an hour to make the whole upper part of the medium wet. If this time is not enough, you may set the timer to prolong the cycles. It is also possible to spray the upper half of the growing medium with water in addition to the regular pump-triggered watering. Remember that soil-based part should never be soaked in water – being moist is enough for.