Injection Option

SUPERtips by Tom Walker

Republished from Golf Course Management magazine, July 2004.

Inverness Club, in Toledo, Ohio, has a reputation for firm, fast greens, and aeration is the foundation of the putting green management program.

The club has hosted eight major championships including four U.S. Opens and two PGA Championships. So before we hosted the U.S. Senior Open in June 2003, I had some decisions to make about aerating the greens and approaches.

The superintendent here since 1980, I am only the fourth superintendent since the club was founded in 1903. When it comes to aeration, I have some long-held beliefs on the topic. Of course core aeration is a firmly established technique for strengthening turf plants and relieving compaction, but I chose an alternative in preparation for the U.S. Senior Open. I was concerned about surface disruption. Also, I wanted to get sand down into tile soil and give the greens a good topdressing at the same time, and I didn’t want to lose time trying to work sand into the greens through other techniques.

This time around I tried a process called DryJect aeration/sand injection. Based on a so-called "venturi vacuum technology," the dry injection technique provided us with a few benefits not offered by other aeration systems. With dry injection large amounts of dry material fill each hole, drawn into the hole by a powerful venturi vacuum, or suction effect, generated by a burst of water moving at high speed into the soil profile. The result is that every hole is filled to the surface, the green is lightly top-dressed, and the putting surface is playable immediately.

In addition, compaction is relieved through a horizontal fracturing or shattering effect that breaks through layering. Based on my experience, the root zone is amended, drainage is improved and the courses labor requirements are minimized. The system draws sand into the soil profile at a rate of somewhere between 3 and 7 cubic feet per 1,000 square feet, depending on hole spacing. I’ve found that a typical 5,000-square-foot green can be treated and ready for play in about one hour.

DryJect is capable of injecting large volumes of a variety of dry materials into the soil structure, including sand/top dressing, diatomaceous earth, calcined clay, granular insecticides, herbicides, fungicides, biologics and root stimulants.

While I recognize that the aeration/sand injection system definitely isn’t a cure-all, I wanted to inject sand down into die holes in small channels and topdress at the same time, so it seemed like a good idea. On the second Monday in April, we did all 18 greens in one day, so the speed of the technique met my objectives in preparing for the tournament.

It left some very minor holes, but these were puttable and not a problem. Compared to how greens can be soft and spongy following core aeration, sand injection firmed up the greens to the proper degree, and put sand exactly where I wanted it. It injected the sand right down through the thatch and into the root zone. In my opinion it definitely promotes excellent drainage and helps the greens dry out more easily. The greens recovered rapidly, and the course looked great in time for the championship. I am excited that I have found another very effective tool to keep in the aeration arsenal.

Tom Walker is superintendent at Inverness Club in Toledo, Ohio, and a 24-year GCSAA member.