As I have said before, the vast majority of domestic lawn problems come down to its feeding. That is not to say you can’t over feed a lawn, most people will have seen a lawn scorch where a heap of fertilizer has been left on it killing it. I also remember reading a report many years ago that some golf greens had been fed so heavily that the soil they were growing in could have legally been sold as fertilizer! So what to do? Clearly feed the lawn. Yes, I know it will make the lawn grow more and it will need cutting more – you will still only get round to cutting it at the weekend anyway.
If you read gardening books they will tell you about feeding a lawn in the spring and autumn, with more nitrogen in the spring to encourage lush growth and less nitrogen in the autumn to encourage less lush growth. There is though a problem with this, we know nitrogen is one of the most important plant nutrients but, there is always a ‘but’, nitrogen is not held in the soil and we don’t actually have any usable method of measuring the nitrogen that is in the soil. The latter we can nothing about the former we can. If the nitrogen is going to be leached out of the soil quite quickly, and the interaction between nitrogen and the remainder soil constituents is a very complex one, clearly the answer is to feed the lawn a little and often.
How often? About every 6 weeks during the growing season is probable about right. As to what to use, well a professional groundsman will use a specialist turf fertilizer but in practice: one you are not going to have access to these and two: unless you are looking after something like a golf course it will make no practical difference. In reality any general garden fertilizer will do the job, the fact the lawn is being feed and feed regularly is far more important. This way the grass is going to be well feed and able to outcompete weeds and diseases. Thus you will be well over half way to a good lawn capable of putting up with the use and abuse garden lawns live with. That is not to say it will not need occasional treatments but these should be the exception rather than the rule.