Hanging gutters: A summary of the current situation


The use of hanging gutters of one style or another has attracted the interest of progressive growers on both sides of the Atlantic writes Douglas Marlow, Grodan A/S Technical Consultant in North America. Leading the charge are growers in the Netherlands, Belgium, the Canadian provinces of Ontario and British Columbia and the US states of Arizona and California.


Overview
The installation and use of hanging gutters has increased dramatically over the past year or two. As it stands today, and the numbers fluctuate depending on the day and who you speak with, there appears to be slightly more than 100 ha of tomatoes on hanging gutters in North America and about 100 ha in the Netherlands and Belgium. In addition to this, there is also approximately 300 ha of roses, 100 ha of gerbera and 70 ha of strawberry in Holland alone. Some growers are experimenting with gutter systems for pepper and cucumber but this has not really taken off yet.


Current designs

Green Meteor is one of the leading companies, in a field of about four Dutch firms, that offer hanging gutter systems. The gutters are constructed of heavy steel coated with a plastic resin. The gutters are usually available in widths ranging between 10 and 30 cm and, through the use of mobile profiling machines, lengths according to the various needs of growers. Runs as long as 300 m have been created.

The original design of the gutter was a ‘U’ shape. Located on either side of the inside of the gutter were two 3 cm deep drain channels. These were to conduct the slab run-off to the end of the nursery. The slab sat inside the gutter but unfortunately, the edges of the slab tended to sag into the 3 cm deep drain channels. This created drainage and disease problems. To correct this, thin sheets of styrofoam were put into the bottom of the gutters to support the slab. However, growers were still concerned about disease problems associated with proper drainage.

In order to solve the problems associated with the ‘U’ design, manufacturers turned the gutter upside down. This new design is called the ‘plateau gutter’. The width is generally between 24 and 30 cm across the upper surface. Along both sides, there is an upturned 3 cm lip to conduct the excess nutrient solution to the end of the nursery. With this design, there is significantly less risk of root contact with the run-off. The added benefit of the plateau gutter is that it is also structurally stronger than the ‘U’ design gutter. Consequently, supports are only needed every 5 m which has the benefit of less light interference.
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