What is hydrojecting?

One of the key elements to healthy turf is oxygen. As turf managers, we need to aerate the greens from time to time to help maintain them and support the grass plant we are trying to encourage.

It’s said that one group of four golfers will put over six hundred steps over a green and around the hole. Add some caddies and that suddenly becomes a lot of foot traffic for one group. Times this by days, weeks and months and you’ve got some amount of compaction. Include all the work we do to the greens like mowing and rolling to produce smooth, true surface and the grass plant is suddenly under a lot of stress.

If we don’t relieve this compaction, the greens will start to suffer which could result in turf thinning. There are many forms of aeration to help prevent this including verti-draining. This is more disruptive but is necessary after an extended period of heavy traffic so we usually leave this for the winter months. One machine we have which causes minimal disturbance to surfaces is the Toro Hydroject.


This machine injects high-pressured water into the surface making a hole every few centimetres. The great benefit of this is you don’t have any heave from a tine being pulled back out which can cause an uneven surface.

The Hydroject is connected via a hose to an irrigation valve; these are found around the course and usually close to greens. Once connected, the water is turned on to build up pressure in the machine. Building up the correct pressure allows the water to be injected at different depths into the profile.

Once we’re happy with the pressure, a speed is selected to determine the hole depth and then we slowly work back and forth over the turf. It’s quite a slow process with three to four greens completed over a four-hour shift. It normally takes us just over a week to complete all greens on the course as we try to finish ahead of golf in the morning.

We prefer this method of aeration during the high season as it has minimal disturbance to the surface and should have no effect on putting. As you can see in the following photo, the knife is pointing to the hole created which otherwise you would struggle to see.

The next two photos show what is happening underground. In the first, you can clearly see a channel has been made deep into the green’s profile.

Below you can see how deep it’s gone beside the hole. This is roughly 7-8 inches deep. If you look closely, you can see a tear drop shape at the bottom.

The benefits of aerating can be seen in the next photo. New, white healthy roots are visible down one of those channels. The deeper the roots, the healthier the plant will be. It will flourish more consistently and for longer periods of times under stressful conditions.

Like all tasks we complete on the course, we are always looking for minimal disruption to playing conditions with the maximum benefit for the health of the plant. This practice is a great example of that and highlights the benefit of advanced technology in our industry.

Words by Jon Wood, Course Manager – The Castle Course

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