Overseeding and Renovation
After a few years, grass plants grow back less vigorously as reproduction slows down, causing a lawn to appear tired and thin. This also leaves the lawn susceptible to weed invasion. Overseeding is a good way of maintaining a healthy and lush lawn. For best results, carry out the overseeding when you see any signs of the appearance of your lawn deteriorating, as leaving it in this state will encourage weeds and other unwanted plants to germinate and establish, which may then require more effort to rejuvenate the lawn than a simple overseed.
The best time to overseed your lawn is in the autumn but it can also be done effectively in the spring. These seasons give the ideal conditions for grass seed germination. You will need to select the right grass seed mixture, taking in to consideration the mixture that is already established. There is nothing wrong with introducing new varieties if overseeding a complete area but if you are overseeding selective areas, try to match the original mixture.
The lawn should firstly be closely mown to about 2-3cm (1inch) so that you can prepare the soil. Rake the lawn clear of all of the trimmings and the thatch (the layer of dead, organic matter on top of the soil). Rake the lawn again to lightly break up some of the soil or pierce with a garden fork holes up to two inches. It is important that these tasks are done thoroughly in order that when the seed is sown, it gets maximum contact with the soil.
Sow the seed at a rate of around 30-40 grams per square metre or up to 50 grams per square metre if the area is completely bare. See also our advice on sowing grass seed. Go over again with a rake to further ensure that the maximum amount of grass seed gets in to contact with the soil. When sowing the seed you may also want to apply a fertiliser or mix the seed with compost to give further nutrients. It is also important that the newly sown seed is kept well watered - the best time to sow is in fact when there has been some significant rainfall and there is plenty of moisture in the soil.
The whole task of overseeding is aimed at getting the maximum amount of seed to germinate and establish to revive the appearance of the lawn so the right timing and additional effort can pay huge dividends when it comes to the end result. See also caring for your new lawn.