Agriculture & Hydroponics

A hydroponic growing system typically contains three water tanks: clean fresh water, nutrient enriched and pH controlled water, and wastewater. The nutrient enriched and pH controlled water comprises the growth medium for the plants. The pH level and nutrient composition in this water reservoir is controlled using valves and pumps to add nutrients, carbon dioxide, or fresh water. Draining wastewater from the nutrient enriched water reservoir helps to maintain consistent water levels, while adjusting nutrient concentration and pH.

To set up a hydroponic monitoring system, conductivity sensors and pH sensors should be installed in the water reservoir that will be used to supply the plants’ growth medium. Based on the measurement data from the sensors, pH controllers and conductivity controllers signal for the opening and closing of valves or operation of pumps. For example, if nutrient concentration in the water reservoir became too high, the conductivity controller could turn on the fresh water pump to dilute the nutrients. Conversely, if nutrient concentration became too low, the conductivity controller could turn on the nutrient pumps. Similarly, if pH became too high, the pH controller could open the solenoid valve, allowing carbon dioxide to flow into the water reservoir. Carbon dioxide reacts with water to form carbonic acid, which lowers the pH of the solution.

• High nutrient concentration > high conductivity reading > add fresh water
• Low nutrient concentration > low conductivity reading > add nutrients
• Overly alkaline solution > high pH reading > add carbon dioxide

While growers in the Hydroponics industry heavily focus on water quality, traditional growers are increasingly aware of the benefits of close monitoring of solutions used to water crops. Fertigation is a popular growing process that’s designed to combine irrigation with fertilization, which means that fertilizer is added directly to some type of irrigation system. Because of how the fertigation process works, it’s effective when applied to a large area of crops and is able to provide growers with many benefits.

Many growers will use fertigation as opposed to more traditional forms of fertilization because of the belief that fertigation is able to more effectively target the nutrient deficiencies that a plant might have. Fertigation is also known to reduce total water consumption, soil erosion, and the amount of fertilizer growers use. If you want to use fertigation for your crops, this system allows you to control the rate and time at which the fertilizer is released.

If you’d like to make sure that your fertigation system is long-lasting, it’s highly recommended that you test the pH of the nutrient-rich solution that you use for fertilization purposes. If this solution is too acidic, the metallic parts in the fertigation system may eventually corrode. The following offers an informative guide on fertigation and how to manage the nutrients you use.

What is Fertigation?

Fertigation is a fertilizing technique that combines fertilizer with irrigation. In most cases, fertilizer is introduced to irrigation water via a drip system, which allows the fertilizer to be evenly distributed to all of the crops that the irrigation system supports.

Because of the high amount of nutrients that are used with this crop growing method, fertigation is considered to be highly efficient. Keep in mind that water soluble fertilizers and liquid fertilizers can be applied. Regardless of the option you use, the efficiency of your irrigation system may increase by upwards of 80-90%.

Hydroponics is considered a relatively light duty application for pH and electrical conductivity sensors. This makes sense, because typically if a plant can survive in the environment, then so can a sensor. For this reason, hydroponics systems typically incorporate laboratory style pH and EC sensors, which have the benefit of being low cost and easy to use.

Laboratory style pH sensors come in both glass and plastic bodies; plastic bodies are favored for hydroponics applications, since they are more durable. Glass bodies are used when chemicals in solution are likely to react with the polymer body material, but this is not typically an issue in hydroponics.

Laboratory pH sensors are designed with junctions that separate the sensor internals from the liquid being measured. Most hydroponics measuring systems can use single junction pH sensors with good results. Double junction pH sensors offer added protection against contamination of the sensor reference system. This protects the sensor from “reference poisoning,” which may extend the sensor’s lifetime in solutions that contain chemicals that react with silver.