Fertilizer types

Fertilizers for fertigation are available in 2 main forms – liquid and dry powder.

Liquid fertilizers

If available, liquid fertilizers are easier to handle since they are predissolved and can be injected into the irrigation system without any additional action. However, they are not always available, might cost more, and take up a lot more storage space.

Dry powder fertilizers

Dry fertilizers must be dissolved before application. It is recommended to use a dissolving aid – such as an air blower, circulation pump, or a mechanical stirrer.

When using dry fertilizers take caution, some fertilizers when mixed in high concentration can precipitate and clog the system. Phosphorus and calcium fertilizers are a good example. If in doubt always use fertilizers compatibility chart.

In any case always make sure that the fertilizers are 100% fully water soluble (usually stated on the label).
A good rule of thumb: 20% of dry fertilizer to the volume of water in the fertilizer tank.


Bio-stimulants are widely used in fertigation as well. As there are many forms of bio-stimulants used, make sure to use only fully water soluble bio-stimulants.

The bucket test

1. Add 2 kg (5 lbs) of the fertilizer mixture you intend to apply through the drip system into a 10 liter (2.5 gallon) bucket with your irrigation water (it must be the same water you are using in the system), and fill to the 10 liter (2.5 gallon) mark.

2. Mix thoroughly and let it sit for 1 hour.

3. If the mixture is cloudy, or if there is a precipitate in the jar, do not use the fertilizer in the drip irrigation system.


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