The grass is greener after a cold winter

Dr Peter Kettlewell, a crops specialist at the university college, says grass growth in the summer varies greatly from year to year because of differences in the amount of water in the soil. The team he has headed has discovered that a cold winter produces higher levels of moisture, leading to a better crop, while warm winters reduce levels and create a less lavish lawn.

Dr Kettlewell has produced his findings in the latest edition of Proceedings of the Royal Society Biological Sciences, alongside fellow team members Jenny Easey, David Stephenson (Reading University) and Paul Poulton (Rothamsted Research).

He said: “Recently, summer weather over much of the UK has been shown to be linked to a climate pattern the previous winter, known as the North Atlantic Oscillation (NAO). After studying a long term field experiment at Rothamsted in Hertfordshire, we have discovered that this winter climate pattern is correlated with grass growth the following summer. This is because the higher the NAO index in winter (which gives a warm winter), the drier the soil in summer, leading to less grass growth.”

The findings will be of direct interest to farmers, gardeners, landscape designers and householders.