Draft:Verti-Drain

Invention and early adoption

The Verti-Drain was developed in the Netherlands by the de Ridder family as a mechanical version of a traditional turf-maintenance technique in which a fork was inserted into the ground and then levered back to loosen compacted soil.^[1] It was designed to emulate the "raise forking" method used on Dutch golf greens.^[1]

Shortly after its development, Cees de Bree became involved in the machine's international distribution and later co-founded Redexim, which subsequently became its manufacturer.^[4]

The machine was introduced to the United Kingdom in the early 1980s, where adoption came through contractors after an initially difficult introduction.^[1] By 1989, the Verti-Drain was in regular use at St Andrews.^[1]

Commercial development

The Verti-Drain played a role in Redexim's international distribution history. Charterhouse Turf Machinery distributed the Redexim Verti-Drain in the United Kingdom for more than 35 years, and became a wholly owned Redexim subsidiary in 1997.^[5] After the Verti-Drain, Redexim expanded its product portfolio to include overseeders, topdressers, verticutters and renovation machinery for natural-grass surfaces, as well as equipment for artificial turf.^[5] Charterhouse was renamed Redexim in 2021 as part of a rebranding intended to align the company's United Kingdom operations with the Redexim name used elsewhere.^[5]

In the United States, the Verti-Drain was the subject of patent-related litigation. In 1997, Redexim and Southern Green settled a two-year legal dispute concerning intellectual property rights in Redexim's patented Verti-Drain aeration equipment.^[6] Southern Green had distributed Verti-Drain systems from 1987 to 1993 before marketing a competing aeration machine.^[6]

Deep-tine aeration mechanism

The Verti-Drain is designed for deep aeration of compacted turf soils.^[3] Soil compaction can restrict aeration and water movement near the surface of golf-course turf, while aeration is used to admit air into the soil at different depths, improve water movement and support root function.^[3]

Unlike aerators that simply drive a tine into the ground and force soil sideways, the Verti-Drain uses tines that penetrate the soil and then gently heave it.^[3] The machine lifts the soil, creating cracks and fissures below the surface while maintaining surface levels.^[3] Depending on tine length, the cracking effect was reported to reach depths of up to 16 inches.^[3] This action can relieve compaction, break up pan layers, release trapped gases and allow oxygenated air and water to move through the soil profile.^[3]

The operating effect depends on both penetration depth and lift; shallow penetration without lifting can be achieved by less disruptive machines.^[1]

Models and variants

Early Verti-Drain models were produced in different sizes for different turf applications.^[3] A 1987 article listed a 1.2-metre "Popular" model requiring at least 17 horsepower, a 1.45-metre "Greens" model requiring 30 horsepower, and 2.0- and 2.5-metre sports-ground models requiring 70–80 horsepower.^[3] The same report described the use of solid and hollow tines in different diameters and spacings.^[3]

Later models included smaller machines intended for areas that were more difficult to access. In 2000, Redexim Charterhouse demonstrated the Verti-Drain 7007, a smaller and more manoeuvrable version of the larger Verti-Drain aerator.^[7] In 2014, the Redexim Carrier was described as a multi-function power unit that could carry a Verti-Drain 1513 implement and provide the same patented forced-heave action as other Verti-Drain machines.^[8]

Golf courses

Verti-Drain machines are used on golf greens, tees and fairways where compaction affects drainage, oxygen movement and root growth.^[3] The machine was especially associated with contractors in Britain during its early adoption, because it was most economical where large turf areas or more than 18 holes were involved.^[1]

At De Hoge Kleij golf course in the Netherlands, a Verti-Drain 7416 was used every six to eight weeks during the growing season.^[2] The article described the 1.6-metre-wide model as lighter than larger models and suitable for use behind a smaller tractor.^[2] The course used 12 mm tines on greens so the surface layer could close more quickly while channels remained open below the surface, improving drainage and root growth.^[2] Combining the 7416 model with a larger Verti-Drain using deeper tines was reported to have improved subsurface connections and drainage on the greens.^[2]

Sports fields and other turf surfaces

The Verti-Drain has also been used outside golf-course maintenance.^[3] Sports-ground Verti-Drain models were intended for larger turf areas, including models described as suitable for fairways.^[3]