Firmness in Greens

The Clegg hammer measures the deceleration of the fall of a 2.25 kg free mass from a height of 18 inches above the test surface. The impact produces an electrical pulse, which is converted to units of gravities. As an example of good firmness, values ranging from 70-125 g were found in studies conducted at Santa Ana Country Club, USA (PACE Turf).

Ferguson, head groundsman at Wembley, recommends thresholds of 75-85 gravities and a VWC 21% for his football pitch.

The USGA TrueFirm measures the units in inches that the impact produced penetrates the ground. Both are designed to quantify the firmness of the greens. But the Clegg hammer is also used to measure the hardness in other sports surfaces like football fields. The USGA TrueFirm, on the other hand, was created specifically to recreate the impact of the balls. golfand thus assist in the preparation and monitoring of greens for consistency of play. Although both devices are useful for measuring the firmness of the greens. As an example, values of 0.32-0.35 inches were achieved at the 2008 Open at Torrey Pines.

The Truefirm has certain advantages such as light weight and minimal impact and damage to the green.

It is also well known that firmness, no matter what equipment is used, is closely related to the moisture content of the substrate. More moisture tends to cushion the green and less moisture stresses it and keeps it firm (always bearing in mind that there is a second factor, which is the thatch and organic matter, which also influences firmness).

Values 15-25% of VWC  seem adequate for good levels of firmness (PACE Turf, 2006), although the values given in each case for firmness measured by each different device will depend on the particular conditions of each green.

In any case, firmness seems to be more related to the characteristics of the subsurface zone. In particular the thickness of thatch and organic matter content. And not so much in the varieties of the different greens. For this reason, the management of these greens, both through the application of light topping and the elimination of thatch  through scarification seem to be the most suitable operations for their management.

The fact that the Trufirm is endorsed by the USGA, as shown in the following image, leads us to believe that it will be used as the standard in the golf industry, although it is true that the Clegg hammer seems to be the option that may prevail in football.

Tiloom offers all this instrumentation for correct monitoring and optimal management. Do not hesitate to contact us for any enquiry or need at info@tiloom.com.

You can purchase each of the versions of Clegg or Trufirm hammer in the following links:

• Clegg hammer 0,5 Kg with BT.
• Clegg hammer 0.5 + 2.25 Kg with BT.
• Clegg Hammer 0.5 + 2.25 Kg.
• Clegg Hammer 2.25 Kg.
• Trufirm

Ask us if you have any questions!