Generating recovery before the main growing season

Done and dusted.

January 15, 2020
5 mins
Henry Bechelet
ICL Turf & Landscape Technical Manager

Winter tends to be a time of decline for all types of turf. The greens in particular will have been under significant pressure from play and being under attack by fungal pathogens. Even with good drainage and an open aspect to light and airflow it is difficult to maintain good playing surfaces through this period. Indeed, we spend a great deal of time and effort throughout the year with our general maintenance trying to minimise the potential for winter decline. Winter is long enough. 

Late winter/early spring is the time when we look to generate recovery from all forms of turf deterioration and get on with the business of preparing the surfaces for play.  A growing trend in greenkeeping in the UK and Ireland in recent years has been to proceed with the aeration and top dressing work as early as possible. This could involve tining and dressing individual greens when surface and course conditions allow in Jan/Feb/March rather than waiting for a window to get them all done together in April/May. The aim being to get them all “done and dusted” in good time for the start of the main playing season, which tends to kick off with the Masters coverage.   

The benefits of taking this early proactive approach are potentially huge for the course manager.  Treating greens individually is certainly a less demanding programme of work than tackling all the greens at once. Also, by doing one at a time you can really take the time to fill the tine holes with a little extra attention where required.  In Jan/Feb/March you don’t tend to get too many complaints from golfers because the extent of the disruption is minimised and the work is being carried out at a time when they might be a little more conciliatory in their attitude.   

Being able to get on with this work early is dependent on the establishment of growth.  The greens need to be actively growing to be able to withstand and recover from top dressing.  The received wisdom passed down to us was that it simply is not possible to establish growth “before the grass is ready” or “you are asking for trouble” if you try to move things along early.  This attitude has been the reason in the past for us trying to tackle our renovations after the Masters, which has never gone down well with the golfers. Even the more modern ‘growth potential’ for grass type models don’t appear to encourage a proactive approach by predicting that there will be little growth available before the start of May. 

ICL field trials over the years have repeatedly shown that if the soil temperatures are above 7oC (and turf health is good) then early spring growth can be stimulated with the application of the right fertiliser. The trick is to choose the right formulation to encourage the onset of growth without any negative consequences such as the accumulation of thatch or the development of disease. It is clear from our trials that it is weak and unfed turf that is most likely to get diseases such as Anthracnose or Microdochium at this time. 

The analysis of your early spring fertiliser analysis might be influenced by the soil nutrient status but essentially the growth response will be driven by the application of nitrogen (and more specifically the sources of N and rate of application).  There will only be a response from phosphorus or potassium if there is a genuine soil deficiency or if availability is in some way being restricted. The inclusion of sulphate of Iron is common in early spring fertiliser formulations because it promotes a quick colour response, it can discourage the development of moss and it can help slow down the rate of development of disease.  

Our field work carried out in recent years during late winter/early spring shows that fertilisers containing sulphate of ammonia as their N source produce the best growth response at lower temperatures (above 7oC). The turf will respond from the application of nitrate N but we find that it is less effective than sulphate of ammonia (which is why we don’t use nitrate in ICL granular fertilisers). The application of urea N will also give a good and immediate response.  The response from organic sources of N is slower (because it needs soil microbial conversion) and for this reason we think that they are not ideal if you need to generate a quick response at lower temperatures. 

The rate of fertiliser application will also govern the level of response. Our aim at this time of year is to generate recovery without producing excessive levels of growth. For example, Greenmaster Pro-Lite “Invigorator Plus” 4-0-14 +8Fe applied at 30 g/m2 (supplying a total of 12 kg of N/ha as sulphate of ammonia) will deliver 2-3 kgs of N/week over a 4-6 week period and will create a healthy growth response given suitable conditions. On the other hand, Greenmaster Pro-Lite “Cold Start” 11-5-5 +8Fe applied at 25 g/m2 (supplying a total of 27.5 kg of N/ha as sulphate of ammonia and urea) will deliver 3-4 kg of N/week over a 6-8 week period. So, the Cold Start will provide a greater response and continue to release over a longer period, which is ideal for recovery through heavy or multiple early top dressings.  

So, we all agree that being able to complete our early season greens preparation work before the Masters would be ideal. This is perfectly possible if greens are tackled individually, in suitable conditions and supported by the right nutrition. There are a wide range of fertilisers to choose from at this time of year, just make sure you choose the ones that have been designed for the required response. Talk to one of our team of specialist advisers if you need help deciding. 

Photograph caption: ICL Spring Fertiliser Trial (22-04-2016) – 15 days after fertiliser application and 7 days after heavy top dressing (applied at 2 kg/m2).