Many greens are getting up in age, which mean the growing medium known as “the rootzone” is getting old too. A serious problem, yet little known, is the loss of capillary action. Capillary action is a pulling behavior of liquids through narrows spaces which can defy gravity (think of a paper towel sucking up water). This action is vital to drainage and a healthy rootzone.
There is a very limited number of chemicals that can be used by golf course superintendents in Germany and many EU countries today. This makes it challenging to maintain water loving, shallow rooted poa annua putting surfaces. Reseeding with Agrostis/Festuca Grasses or even Rye grasses can help decimate Poa annua, conserve water and reduce chemical needs over the long term, but more than simply reseeding need be done.