Fertigation Injection & How Long to Inject

In two steps. First the stock-solution volume = fertiliser required ÷ stock concentration, which is how much of your made-up stock contains the dose. Then injection time = stock volume ÷ injector flow rate. The tool reports the stock volume and the run time in both minutes and hours so you can set a timer or controller.

It is the concentrated fertiliser solution you mix in a tank and meter into the irrigation line. Its concentration — say grams of fertiliser per litre — sets how much solution carries the dose: a stronger stock means less volume to inject. Knowing the concentration is what lets the tool turn a fertiliser quantity into a volume and then a time.

It is how fast the injector or dosing pump pulls stock into the irrigation water, in litres per hour or per minute. A Venturi, a positive-displacement dosing pump or a proportional injector all have a flow you can set or measure. Dividing the stock volume by this flow gives the run time needed to inject the whole dose.

Injecting steadily over part of the irrigation set spreads the nutrient evenly through the water and across the field, and lets you bracket it with clean water to flush the lines. A measured injection time is what keeps every emitter delivering a similar concentration rather than a slug at the start.

Mix to a concentration the fertiliser can fully dissolve at your water temperature and that your injector can handle without clogging — manufacturers quote solubility limits. A higher concentration shortens the injection time but risks precipitation; a lower one is safer but needs a bigger tank and longer run. Enter whatever you actually mixed.

Yes — inject within the irrigation set and leave time to flush, so clean water clears fertiliser from the pipes and emitters before shut-off. If the calculated injection time is longer than your irrigation run, either raise the injector flow, raise the stock concentration, or split the dose across more sets.

Yes. Venturi injectors, dosing pumps and proportional injectors all reduce to a flow rate, so as long as you enter the flow the stock is metered at, the time calculation holds. Proportional injectors meter as a ratio of water flow, so confirm the resulting stock flow at your irrigation rate before entering it.

Keep them consistent: fertiliser required and stock concentration in the same mass basis (e.g. grams and grams per litre) so the stock volume comes out in litres, and the injector flow in litres per hour or minute. The tool then reports the stock volume in litres and the injection time in minutes and hours.

They are exact for the inputs, but real injection depends on a steady flow, a fully dissolved stock and no clogging. Calibrate the injector by timing a known volume, watch for precipitation in the tank, and check the line concentration on a long run. Use the result to set the timer, then verify on the ground.