Flood-and-Drain Systems

Parts

• There are a number of different styles of flood-and-drain hydroponic systems, but they all have certain basic elements in common. The system centers around a tray which holds a growing medium such as sand, gravel or perlite. This growing medium supports the plants' roots, keeping the plants upright. There is a system for delivering a nutrient solution to the plants' roots, and another system to drain the nutrient solution out of the tray and store it for reuse. This alternating flooding and draining of the roots is what gives the system its name.

Advantages

• One of the advantages that the flood-and-drain system has over other hydroponic systems is that the plant roots are not continually immersed in water. Many hydroponic setups, such as the water-culture system, do not provide adequate air to the roots, which can stunt growth and cause rot and infection. It uses fewer and simpler parts than the aeroponic or continuous flow systems, making it less expensive and easier to set up and maintain. Some flood-and-drain systems do not use any pumps or mechanical parts, so they will need less maintenance and repair.

Types

• The simplest type of flood-and-drain system has a simple drain hole in the bottom of the tray, emptying into a storage bucket. Nutrient solution is delivered to the tray with a watering can or gravity-fed system. Other types use pumps and timers to deliver the nutrient solution. Some drench the growing medium all at once, while others apply a little solution at a time; some pour into the top of the tray, and others pump the solution into the bottom.

How to Use

• The nutrient solution should be pumped to within 1 inch of the surface of the growing solution. The flooding and draining cycle should take between 10 and 30 minutes if done properly. Flooding and draining should be done at least once every day, in some cases more than twice, depending on what you are growing and the specifics of your system. Do not reuse the same solution for more than two weeks.