Maximum Yield USA May 2018 | Page 63

In water culture hydroponics, either deep water or nutrient film technique, there is no percola- tion. The liquid nutrient does not pour through the grow medium but rather is run across and through the root systems of the plants involved. Because of this, nutrients are not rinsed out on a continual basis. Instead, they are recirculated. Nutrients are only removed when the system is drained and cleaned. The temperature and absence of light in the water, as well as the general cleanliness of the tank, feed lines, and pump, will have major impacts on just how long a system can go between rinsing and cleaning. Typically, between one and three weeks seems to work best. If growers change the water more often than necessary, their workload and nutrient costs go up. If they change it too seldom, the likelihood of increased harmful microorganisms and plugged up system components can go up. Finding the balance is important for every grower. Healthy plants require good nutrition and they are much more likely to put off the chemicals from plant allelopathy, which fight off competition from other parasitical plant life forms. With soil systems, the intent is to create healthy and plentiful living and beneficial microbes to assist the root system’s uptake of nutrients. However, much of the organic food that builds healthy microbe populations will also support many undesired bacteria and fungi. As such, many water culture growers prefer to use ionic nutrients. These are the nutrient salts that beneficial microbes create when they react with organic non-ionic nutrients. This lack of a food source will aid in keeping harmful microbe populations from developing. On the other side, fungi- like mycorrhizae, which are still very beneficial for deep water culture crops, will also not have any support to develop and grow. If growers decide to use organic nutrients in a deep water system, it is recommended they make routine changes. Growers should also clean the solution, keep light from entering the water reservoirs and channels, and keep the oxygen- ation of the water at its maximum. Though not generally considered a plant nutrient, oxygen is a primary nutrient required by the root system. A lack of oxygen can aid in the development of anaerobic bacteria, which is undesirable. “Another aspect that has a major impact on the uptake of many nutrients and needs TO BE CAREFULLY MONITORED IS PH.” grow cycle 63