For many lawn care experts weed grasses are a cause of aggravation and stress. Weed grasses can pollute an otherwise healthy lawn; additionally if they are not treated they will grow and spread.
In some cases if a weed grass populates too much of a lawn then it may become unsalvageable. In these cases the use of a rotavator may be needed to actually lay down new turf or reseed the area. Thankfully however, most lawns can be saved if they are treated in a reasonable amount of time.
The first thing to do is prepare your lawn for treatment. One of the easiest ways to do this is to skip one weeks cutting and let the grass grow a little. This allows you to properly identify the full extent of the weed grass colonisation. It also makes tackling and targeting the areas for removal a little easier.
Before you jump in and start tackling your weed grass you need to protect yourself. This involves at least wearing protective gloves, but should ideally include overall chemical protective clothing. To kill the weed grass you are going to want to get a circular plastic container or a plant pot roughly the size of the affected weed grass patches. With this you will be able to apply the weed killer to only the affected areas without poisoning healthy turf grasses.
Cut the bottom out of the plant pot or container so you have an open ended cylinder to apply your weed killer through. Simply place the container over the patches so that a divide between the healthy and affected grass is created. Once you have done this you can apply the weed killer directly to the weed grass. Apply an ample amount of weed killer to each patch of affected grass individually. You may want to mark them out in advance so that no spots are missed or are double sprayed.
After you have applied the weed controlling substance do not walk on the lawn for several days. This will allow the weed killer to be absorbed and avoid it being spread to healthy grass. After a few days you can mow the lawn again as normal whilst you wait for the bad grass to die off.
Once the patches have died you should dig them out with an appropriate garden tool. Place some rich composed soil into the void and reseed the patches using an appropriate lawn seed. You will want to seed the patch a little wider than its radius. This is so that the old and new lawn grass fuses nicely and do not show any divides.