Home » Can you measure bowls green smoothness and trueness?

measure bowls green smoothness and trueness
just watching a golf ball roll on the (bowls) green surface can tell you a lot about smoothness and trueness

Can you measure bowls green smoothness and trueness?

Can we accurately and objectively measure bowls green smoothness and trueness?

Last time I proposed a hypothesis on bowls green performance that goes a bit like this:

  • Bowling Green Surface Trueness and Smoothness are correlated with green surface firmness (firmer greens are smoother and truer).
  • Bowling Green surface firmness is correlated with soil moisture content (wetter greens are less firm).
  • Soil Moisture Content is correlated with Soil Organic Matter Content
  • Therefore the Performance of Bowling Green Surfaces is correlated with Soil Organic Matter Content.

But, how can we objectively measure how smooth or true our greens are?

First of all let’s define trueness and smoothness.

Green Trueness

The trueness of a bowling green is often called into question by bowlers. Just when you think you are performing at your highest level of ability all season, you visit a green where you just can’t find the “roads”, or when you do, and your most sweetly delivered shot suddenly swerves off line and stops a meter away from where you thought it would. Green Trueness is a measure of how much horizontal, (side to side) movement of the wood is induced by discrepancies in or on the green surface. 

Green Smoothness

Green Smoothness is often noticed when the greenkeeper would rather it wasn’t i.e. when it’s not smooth enough! Smoothness is defined by how much vertical deviation (bounce) the wood encounters on its way to the jack. Smoothness can also contribute to the wood going off line or against the draw.

Snaking and Bobbling

It might help to think of trueness (linear or horizontal deviation) as “snaking” and smoothness (vertical deviation) as “bobbling”. Can snaking and bobbling be measured? Yes they can and very accurately too. There are various tools available to the greenkeeper as follows:

  1. Golf ball and eyes: I always carry a golf ball with me when I look at greens (bowls and golf). Simply rolling a golf ball along the surface and watching it’s movement can tell you a lot about the smoothness, trueness and speed of the surface. This of course is back to greenkeeper’s nous and not at all objective.
  2. Parry Meter: This is a piece of equipment developed by a greenkeeper that utilises the power of the iPhone to make measurements of trueness and smoothness. More on the Parry Meter below.
  3. Trueness Meter: This is a proprietary tool developed by STRI with help from the R&A. See last video below for more info on this.

Who cares?

Smoothness and trueness of green surfaces can be measured objectively it seems, but does it matter? As you can see from the videos and probably glean from your own experience, these measures, although accurate are also momentary. Depending on conditions, the very act of taking the measurements could have an affect on the result from a repeated test. These machines come into their own when conditions are already pretty good.


However, even smoothness and trueness when measured as accurately and as impressively as this are but symptoms; they are the effect rather than the cause, so we have to dig deeper into our hypothesis to get to the real answer to creating the smoothest, truest bowls greens. If you look back at the hypothesis at the beginning of this article you’ll see where we have to go next…surface firmness.

Next time we’ll look at bowls green surface firmness and discuss some of the methods available to us for making objective measurements of that.

Meantime, don’t go spending your Christmas vouchers on any fancy equipment, as we will see, as we work through this that although nice to have, these measurements are unnecessary in the production of a high performance bowling green. Knowledge of them, however, is very useful indeed.

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