Well what a month January turned out to be – from minus 5 deg C up to 13 deg. We had Snow for 2 days, frost and my lawn is still covered in water having had 4 inches of rain over the month.
Unfortunately this has delayed the planned application of winter lawn tonic and moss control – so lets hope February is better. What is really noticeable is the incidence of struggling turf that was laid last year . The turf has still not fully established and put roots down and tends to be very dense, the wet conditions have resulted in the roots sitting in water and not getting any oxygen.
Getting a lot of inquiries about lawns that are sitting in water which has identified areas of poor drainage, not easy to solve especially on clay soils where the ground may have become compacted. Or the surface has thick thatch and moss and water cannot get through.
You have to remember that all soils can only absorb so much water – we refer to this as Field capacity, it is the amount of soil moisture or water content held in soil after excess water has drained away and the rate of downward movement has materially decreased, which usually takes place within 2–3 days after a rain or irrigation – basically you can only get so much in a pint pot, before it over flows.
If it’s a surface problem it can be resolved with scarification and aeration and top dressing with a good compost this will open the top 15cm up and allow water to get through.
If its clay we have two options we can apply gypsum which causes the clay particles to flock together increasing the particle size which will help improve drainage, but this is a slow process and can take 2-3 years, and will not always resolve the problem.
In the USA who are regarded as the experts in lawn care and who we tend to follow there is increasing use of treatments that can be sprayed on to the lawn which can improve drainage with out the need for scarification which can be quite aggressive – it’s a new idea in its infancy so we will might look at trialling it later this year.
The other option is to put in a drainage system, this is the most expensive option and if the problem of water sitting on the surface only occurs every few years you might be better to put up with it. If not the most common method is what is known as French drains – trenches are slit into the soil and back filled with gravel up to the surface, this allows water to drain away – often the drains slope way into a ditch where water can move away or in to a soak away.
Its important to mark where the water did sit on the lawn as in a few moths time when its dry it will soon be forgotten , and then if need be the repair work can commence .