Fertigation: Fertilizing Through Irrigation

March 27, 2017   

Precision in growing methods can be a lifesaver for any growing operation or greenhouse business. Many farmers have experienced the excessive loss of water from using overhead sprinklers. Overhead systems can leave your plants susceptible to disease and pests, which has driven many of today’s farms to implement more efficient irrigation and fertilization systems. Applying nutrients through an irrigation system provides a direct line to the roots of the plant. Because of this, there is a growing popularity of fertigation systems across the agricultural and horticultural industries. There is also an increasing concern from the marketplace to lessen the impact of agricultural production on the environment, and to achieve accuracy and minimize wasted materials, a fertigation system might be the next addition to your greenhouse operation.

Benefits of Fertigation

Fertigation is the process of fertilizing crops through an existing irrigation system. Most fertigation set ups use existing drip tape or hydroponic systems to deliver nutrients. Though fertigation techniques can be used in conjunction with foliar sprays or other application methods, an efficient fertigation system can eliminate the need for foliar spraying all together.

There are various benefits many growers find to installing a fertigation system. Integrating a fertigation system can help limit water and nutrient waste for large operations, and it ensures that fertilizer nutrients are available to the root zone of a plant. As opposed to foliar spray, fertigation minimizes fertilizer application rate and increases the efficiency of fertilizer use.

Another major benefit is the avoidance of foliar sprays and the ability to water in the evenings. When using foliar sprays or overhead irrigation systems, water tends to collect on the surface of a plant’s leaves, which if left overnight, can lead to the development of foliar damage or the formation of fungus. Fertigation techniques also reduce fluctuations in soil, fertilizer costs and water waste.

Tips for Fertigation

Make sure to use a water soluble fertilizer to avoid blockage and uneven nutrient distribution. A recommended practice is flushing the system after applying nutrients to keep the lines clean and clear of any debris that may cause corrosion or clogging. Different plants have different nutritional needs. It is therefore unwise to apply nutrients at the same constant for all of your crops. Nutrients should be applied very specifically to your plants’ needs and the stage of their life cycle.

When using a fertigation system, growers must compare their readings to their target nutritional values and make adjustments for particular conditions like life cycle, soil type, electrical conductivity of soil, foliar readings and uneven distribution.

When running your irrigation system, do not over-water, as some nutrients, like nitrogen, might leave the favorable area near the roots and leach into the soil. When using fertigation, the uniformity of your nutrient distribution depends on the uniformity of your irrigation system. Consider pipeline length and consistency for an even flow of nutrients throughout your system. Distribution uniformity is crucial to running a successful fertigation system to ensure nutrients are evenly allocated. To measure whether a system is working optimally or not, a grower can measure electrical conductivity to gain insight into the salinity of a solution or check foliar nutrient levels.

For many vegetables, supplying sufficient doses of Nitrogen, Phosphorus Potassium and other trace minerals are essential for ideal plant growth. NPK are considered major builders of proteins, amino acids, chlorophyll and enzymes. Nevertheless, all vegetables are different, some are heavy feeders and some are light feeders. Heavy feeders, like corn and tomatoes, are known to significantly benefit from fertigation systems, because of their high nutrient application needs throughout different parts of the life cycle. While light feeders also benefit from fertigation techniques, the major key here is that you consider different nutritional needs and not over-feed or under-feed your crops or put all the crops on the same plan. Consult with your local extension center to help with specific crop nutritional needs or issues that arise.

Fertigation Methods

There are a few types of fertigation methods. Two major techniques are quantitative fertigation and proportional application. In proportional application the injection rate is proportional to the water discharge rate. This method is not complicated and allows for increased fertigation during parts of the cycle with high water demand, which when most nutrients are required. Quantitative application is generally used in open field production and utilizes a bypass fertilizer tank. Nutrient solution is applied in a calculated amount to each irrigation block, relevant for automation, allowing accuracy in nutrient application and distribution control.

Using an injector can be beneficial by manually ensuring even distribution throughout an irrigation system. When using injectors, drip irrigation systems should be completely pressurized before injecting. Fertilizer should be injected before the system’s filters, so that the filter traps insoluble particles. Also, fertigation systems should be wired to a pump switch control or a flow control switch in the mainline, so that your system doesn’t run without water flowing. Install a backflow prevention device in between the water source and the injector to prevent fertilizer from contaminating the water source.

Fertigation Supplies

Growers Supply offers products for your fertigation system needs. The HI 2500 Kits are recommended for small to mid-size systems, like the Hydroponic Systems Growers Supply carries. This system offers complete control over pH, EC and TDS levels. It comes with an EC or TDS minicontroller, EC or TDs Probe, pH Mini Controller, pH Electrode, two Blackstone Dosing Pumps and NEMA enclosure. The HI 2500 system comes fully assembled and is easy to clean. The HI5000 Systems are recommended for larger or commercial hydroponic setups that utilize NFT, Dutch buckets or flood tables. Automating dosing can optimize plant health while saving a grower time and labor.

Growers Supply also carries MixRite Horticultural Injectors and injector systems. If supplementing nutrients, cleaning lines or treating water, injectors can be a helpful tool for on-demand amendments.

The iGrow1800 is the latest in greenhouse climate automation. The iGrow1800 is a new system that can be set for 12-38 programmable outputs and comes with an intelligent integrated sensor and override switches. The iGrow1800 can be used to gain complete control over your nutrient output. Control heating, cooling, humidity, lighting and more from one controller. The Link4 iDoser is a compatible addition to the iGrow1800 that can provide automatic dosing of nutrients outside of irrigation times.

Knowledge is power. Fertigation can make your commercial operation less labor-intensive and costly, but you must educate yourself on your crops’ nutrient needs, soil nutrition supply, the technology you are using and figure out a monitoring technique in order to achieve success and uniformity in nutrient distribution.


Contributed by Amanda Williams