IWS Flood & Drain: Problems and Solutions

If you have been considering flood and drain hydroponics or are simply to learn more about the hydroponics method, you have come to the right place. Today we are going to be explaining what IWS flood & drain hydroponics entails, as well as describing the best solutions to the most common problems.

What is flood & drain hydroponics?

Flood and drain hydroponics is a hydroponics method that fills pots form the bottom up. These systems are sometimes referred to as IWS systems by hydroponics suppliers and professionals. As nutrient solution rises within the pots old air is pushed up and out of the pots, and when all solution is drained away fresh air is pulled in allowing rootzones to benefit from enriched oxygen. The more often these systems are flooded the more oxygen the pots are able to trap.

The Best Growing Media for Flood & Drain Growing

When it comes to choosing what growing media to use when growing using flood and drain iws hydroponics, it is simply your choice – However, you should always look for media that boasts low to medium water holding capacity and high air filled porosity. If you as to ask me what media I would suggest – I would definitely tell you to use clay pebbles.

Clay pebbles are lightweight with lots of empty space between each pebbles, creating high air filled porosity. Pebbles use allows people to flood their systems often without overdoing it.

Problems and Solutions


Problem: System will not stop filling and pots are overflowing.

Solution: You could be facing a blockage. Go to the top of your reservoir and you should be able to find a small hole drilled into the pipework, make sure this small hole is not blocked. If this is not blocked you may be looking at a faulty top float switch in your brain pot.


Problem: Some pots are over-flooding.

Solution: Make sure that you do not have an uneven floor; this is one of the main reasons why some pots would be overfilling. For all pots to fill equally they must all be level.


Problem: pH rising rapidly in the reservoir.

Solution: pH tends to rise slowly during normal nutrient uptake. You need to be sure to wash and pre-treat your growing media otherwise you could see rises during early vegetation.