Fertigation Makes Filtration More Important, Not Less

What fertigation actually puts in the line

Fertigation is usually described in terms of what it does for the crop, but it is worth thinking about what it puts into the pipe. Water-soluble fertiliser is dissolved, but it is not pure, and the fillers and impurities in a commercial grade do not disappear because the label says soluble.

Add that to whatever the source water already carries and the filter is now handling two loads at once rather than one.

Why a disc stack copes better with that

A screen filter traps contaminants on a single mesh and blinds progressively: as the mesh loads, the pressure drop climbs. With fertiliser in the water there is more to trap, and a screen blinding at the wrong moment starves a block at exactly the point in the season when the crop is being fed through that line.

A disc filter separates rather than blocks. Our 2 inch disc filter uses a 130 micron grooved disc stack rated to 40 m³/h at a maximum working pressure of 10 bar, and the grooves hold far more dirt before the pressure drop becomes noticeable. Each disc lifts out and can be washed, so a loaded stack is a cleaning job rather than a replacement.

Order of operations on a fertigation line

The usual arrangement puts the primary filter first, then the finer stage, and the injection point after that. Injecting after the filter is what you want: fertiliser goes into water that has already been cleaned rather than through the element that is catching the dirt.

Whatever the arrangement, the indicator that matters is differential pressure. Fertigation changes the load through the season, so clean the filter on the gauge rather than on a calendar.

Specifications at a glance

Common questions

Does fertigation need a different filter from plain water?

The filter still has to remove what is in the water, and fertigation adds to that load. A disc filter copes with the extra load better than a fine screen because it holds more dirt before the pressure drop shows.

Can I inject fertiliser before the filter?

You can, and the filter will then catch anything the fertiliser carries, but it loads the element faster and the fertiliser has to pass through whatever is already trapped there. Injecting after the filter is the more usual arrangement.

How often should the filter be cleaned when fertigating?

More often than on plain water, because there is more to trap. Go by the differential pressure gauge rather than a fixed interval, since the load changes with the fertiliser and with the season.