Trough Benches

Trough Benches

Trough Benches is one of C-Mac's custom built, made to order horticultural benches for subirrigation systems. Continuous lengths of gutter and manufactured in DIY or kit benches using the "Spring Benching System" makes for easy installation.

Trough Benches are also known as "Gutter Subirrigation" or "Trough Subirrigation" benches.

What is Subirrigation?  

Subirrigation is a method of irrigation where water is delivered to the plant root zone from below the soil surface and absorbed upwards. The excess may be collected for reuse.

In general used for potted plants, there are three basic systems:

  1. Ebb-and-flow benches and trough benches,
  2. Flooded floor systems.
  3. Closed, recirculating subirrigation systems,


In this system, Bench-mounted tray enclosures holding pots are filled and then drained. The system consists of a shallow, molded plastic bench top which is flooded with water and fertilizer to both water and feed the plants.

When irrigation is complete, the remaining solution drains from the bench and is pumped back to a storage tank.

Flooded Floor

In this system, Special sloped concrete flooring is flooded and drained.

The entire floor of the greenhouse is covered with concrete carefully designed and installed to pitch toward openings in the floor. Through these openings the irrigation solution enters to flood the floor and, following flooding, the excess drains back to the storage tank.


In this system, water flows through bench-mounted, slightly sloping troughs containing pots. The trough (gutter) is placed on benching that is pitched slightly from the inlet to the outlet end. This helps water flow by gravity.

This system works by running a film of irrigation water down a slightly inclined, shallow metal trough (gutter) holding the plants. The troughs empty into a return channel for recirculation. The pots or flats in the trough have plenty of opportunity to absorb solution as it runs past.

Trough benching at Colouwise Nursery

Why use Trough Bench Subirrigation System?

  • This system is easy to learn and can be fine tuned to suit a variety of crops.
  • Increase Greenhouse efficiency: improves production capacity by having 70%-80% space in greenhouse.
  • Grow plants uniformly and reduce foliar disease.
    • Increase in plant uniformity may be the result of more even and complete moistening of the growth medium and better distribution of nutrients absorbed by capillary flow.  
    • Absence of water on the leaves using subirrigation may result in less foliar disease.
  • Save labour
    • A single person can water thousands of plants by operating the flooding system manually or with the help of a computer.
    • Amount of time needed to water the crop drops dramatically.
    • Decrease in labor need will help free up workers to do other tasks.
  • Save water and fertilizer
    • According to research (see document below), water and fertilizer usage was cut over 50% by using a close system since water and fertilizer(nutrient solution) are recirculated and not lost by leaching or runoff.
    • Less fertilizer is needed, resulting a in lower cost to produce the same quality product.
  • Increase safety (Long term benefit)
    • It is safer for the environment as water containing fertilizers and chemicals will not leach into our valuable drinking water supplies, helping our children and future generations.
    • Less chemicals were needed, cutting down on workers exposure to pesticides and fungicides.
    • Reduce risks of getting injuries among workers when doing repetitious manual handling tasks (391 injuries claims in Nursery and Garden industry in NSW since 2008)
  • Cost effective
    • Existing bench frames can be retrofitted.
    • The productivity of system is maintained at a high level due to 70%-80% space saving in greenhouse and the reduction of labor, water, fertilizers and chemicals etc.
    • Usually trough benches payback time is 2-3 years rather than 5-10 years by choosing other subirrigation system.

Trough Irrigation versus Traditioanl Overhead Watering in a commercial greenhouse operation

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Why use C-Mac Trough Benches?

High QualityGutter Benching or Trough Sub-irrigation

  • Specially made color bond trough (gutter) and heavy duty galvanized steel tube.
  • Extremely strong and light weight
  • AUSTRALIAN MADE product.
  • C-Mac Industries is ISO 9001:2015 Quality certified ensuring procedures are maintained and continuously improved.


  • SPECIAL MADE TO ORDER possible because C-Mac Invests heavily on modular "Spring Benching" system which allows for flexibility in design.
  • The troughs can be obtained in various lengths and widths from C-Mac.
  • All your special orders are at a minimum cost, because the advanced technology of manufacturing the product requires NO ADDITIONAL SETUP OR EXTRA LABOR COSTS.


  • Easy to assemble.
  • Supplied in kit form (minimize transport costs).

Other nursery equipment such as potting bench, Shade house, Trailer, which reduce risk of getting injury and increase work efficiency and production are also available.

Contact us on 02 9631 6000 to make an enquiry OR  Click here for discussion & FREE Quotation