Removing Lawn Grass Weeds Using a Herbicide
It is not uncommon for gardeners to find great therapeutic value in spending hours hand-weeding their lawns. However, most people have neither the time nor the inclination to rid their lawns of weeds in this way. The procedure outlined below is a step-by-step method which can be used to minimise the infestation of lawn grass weeds.
The various areas of South Africa have differing climatic conditions, with frost occuring in some and rainfall affecting the growth of lawns at different times of the year. Generally though, lawn weed removal should be tackled when lawns are actively growing, not when they are in their seasonal dormancy.
Weed Removal Procedure
Weeds can be removed most efficiently by using a selective herbicide, which will destroy broadleaf weeds, but not your lawn. There are several such commercially available lawn herbicides - read the instructions carefully to ensure you are purchasing the correct product. Most products work by absorbtion through the leaves of the weeds, but will not destroy the seeds of the weeds which have not yet germinated. Hence there might be a need for several repititions of the procedure.
ENSURE THAT YOU DO NOT BY MISTAKE USE A GENERAL HERBICIDE E.G. FOR REMOVING WEEDS FROM PATHWAYS. IT WILL KILL OFF YOUR LAWN, SO YOU MUST USE A HERBICIDE WHICH SPECIFICALLY TARGETS BROADLEAF LAWN WEEDS.
For best results, fertilise your lawn 2-3 weeks before applying the herbicide. You may use a brand of refined peletised chicken manure at about 150 grams per square meter, or a high nitrogen synthetic fertiliser at about 60 grams per square meter. Make sure that this fertilser is watered in well.
Then, about one week before applying the herbicide mow the lawn - but avoid cutting it too short.
One day before applying the herbicide water the lawn well. This will ensure that the weeds are under no stress from being cut or lacking moisture, and will therefore readily absorb the herbicide.
Try to plan the above prepararations so that spaying the lawn with the herbicide takes place on a rain-free day. But if rain does occur within six hours after spraying, then simply re-spray. Apply the herbicide at the rate recommended in the instructions provided with your chosen herbicide. This might be something like 60 ml of herbicide mixed in 5 litres of water and applied to 100 square meters of lawn surface.
After spraying, avoid watering the lawn for three days to allow the herbicide to fully penetrate the leaves of the weeds. Experience shows that generally about 95% of weeds will be eradicated at the first attempt. Give the lawn a chance to recover from the spraying (even the lawn grass itself does get "knocked back"), then go through the above procedure a second time.