Feed Circuits (Plumbing)

A well designed feed circuit will ensure all roots are fed and flushed and not prone to blockages.


Aim to make the feed circuit tidy and uncomplicated. To minimize the risk of leaks and blockages avoid junctions and restrictive feed outlets (e.g. drippers) and use filters.

Material selection (pipes and junctions)

Avoid metal because it is prone to corrosion. Plastic components are generally cheaper, more flexible, readily available and last longer.

Pipes:  Flexible plastic tubing (e.g. polypropylene) is usually appropriate for all situations and reduces the need for junctions. Its cheapness provides the option of being discarded once it becomes internally contaminated.

As with other system components that contain nutrient, ensure the plastic is black or opaque. This will help prevent the growth of algae on their internal sidewalls.

For junctions, push-fit fittings are preferred (Fig 2.2). These are quick and easy to install. At high pressures however, they are prone to leaks and therefore require securing with clamps (Fig 2.3).

For the ‘primary’ circuit, rigid black (or opaque) plastic pipes are preferable. These generally require glued junctions. Note that rigid plastics are relatively brittle and therefore inappropriate for high traffic areas.

Maximizing flow rate

● Pipe diameter:  Use large diameter pipes. Do not underestimate the degree to which small diameter pipes reduce flow rates, especially as the length of the pipe increases. Small diameter pipes are also more prone to blockages from salt build-up, dirt, algae and plant matter.

● Junctions:  These also reduce flow rate and increase the risk of blockages. In many situations junctions can be avoided by using ‘flexible’ pipes instead of those that are ‘rigid’.