Flushing Explained

A lot of growers don't know much about flushing. They hear the word and they think about flushing a toilet. Flushing in hydroponics is a little different, and it's something that's good to know about when you are trying to set up your own successful hydroponics project, for either commercial reasons or hobbyist use.

To begin with, flushing does mean cleaning out a reservoir in a lot of cases, but it doesn't just mean getting rid of stuff. It's a much more sophisticated strategy for delivering hydroponic results that helps to grow more vibrant, healthier and robust plants.

Out with the Old, In with the New

In many cases, flushing happens when growers realize that the hydroponic reservoir has become too heavy or clogged with materials.

Growers add a lot of things to reservoirs in order to nurture plants. Nutrient packages go in, as well as pH value adjusters and other elements. Over time, all of this can develop into a kind of clogging mix. Too much dissolved solids in the reservoir can lead to problems. Any kind of algae or buildup from lighting and other factors can be problematic as well.

So growers do use flushing to get all the stuff out of the system and start over. But they also use flushing to make a clean slate, in order to re-build a hydroponics reservoir by putting even more stuff into it.

The Blank Canvas

One of the best ways to think about hydroponic flushing is to make the analogy to painting on canvas. A painter starts with a brand-new clean canvas and start adding paint. In professional techniques, the painter often introduces a bottom layer and top layer, stroking, smudging and adding detail along the way. But then for some reason, he or she is done with that canvas. Either the painter has produced a work that he or she wanted to create, or the canvas is getting too cluttered and the layered paint is getting too thick.

So the painter goes to a new canvas, one that is entirely blank. But then the artist gets going adding new pants to this canvas, to clutter it up just like the old one.

This is the kind of philosophy that often goes into flushing. Growers use flushing, not just to start over, but to give plants a kind of “last meal” before harvest. A lot of times, growers flush out the system not because it's over cluttered, but because plants are almost ready to go to market. Then they furiously add items like proteins, calcium, and last-minute supplements to try to get plants to eat bigger right before they are harvested.

All of this factors into a detailed hydroponic plan that controls temperature, humidity and pH value, while offering the best nutrients for plants at every stage of growth.

For more on hydroponics and how to do it right, check out Dealzer’s product catalog on the major resources we offer to growers - thanks and happy gardening!