Questions and Answersfoobar
Q: I work at a school. We have a number of cricket squares, our end of season renovations took place in August. Since then I have applied to doses of a 6-5-10 fertiliser recomended after having a soil test. Each time the squares green up for about 2 weeks then start to turn yellow. At this moment the squares are looking stressed. I do not want to add more fertiliser as I'm not sure it's working. Can you can help. Thanks
A: Firstly, well done on securing a professional, nutritional analysis to determine the correct fertiliser applications for your facilities. – a very wise decision removing unnecessary guesswork.
Now there are a number of other points to consider outside of the information you have submitted. The pH values are important as is the make-up of the grass sward content of the squares. This information should have been included in your analysis.
Assuming that in common with the contemporary mode of practice you are using a predominately perennial ryegrass (Lolium Perenne) mixture for your squares, for optimum health they ideally require a pH value ranging from 6-7.
If there is a high percentage of Annual Meadow Grass (Poa Annua) encroachment within the sward it does have a tendency to yellow very quickly when under stress.
You state that you completed end of season renovations in August. Since then we have experienced unusually warm and prolonged climatic conditions where grass growth has remained fairly vigorous coupled the plant’s demand for nutrients (and in some areas of the country, irrigation!) may well have required a further application.
However the daylight hours are now shorter and the first frosts are setting in so it is essential that any necessary maintenance mowings are set at a height of 20-25mm with blades kept sharp as a ragged cut will expose the grass leaf to damage by disease, cold winds & frost also lending towards a yellowing appearance of the tips.
Assuming that the pH of the squares is not unduly low, I would advise at this stage of the year to apply iron (Ferrous Sulphate) or chelated iron. This would give a rapid enhanced green-up colour without forced grass growth and harden the sward making it less susceptible to disease. You can apply this throughout the winter when required (avoid applying during prolonged frosty or very dry/cold conditions). The added bonus is that it is relatively cheap to purchase.
You might also consider a bio-stimulant formulate that are on the market. They promote root development and overall plant health (including green-up) during the winter months.
Hope this helps.