New Lawns
Do not use either lawn sand or chemical weed killer on new lawns. Wait 12 months for seed sown lawns and six months for turf / sod laid lawns.

Grass Cuttings
Where lawn sand or chemical weed killer has been used on grass, do not use the first cutting on the compost heap. Later cuttings can be used on the compost heap but the compost should not be used for six months. Do not use newly treated grass cuttings as a mulch around plants.

WHICH WEED KILLER?

Lawn Sand
Lawn sand is more environmentally friendly than other chemical lawn weed killers, so this should be the first choice. It is a mixture of ammonium sulphate, iron sulphate and fine sand. It is used to kill a wide variety of lawn weeds and is especially good at preventing and killing moss in lawns.

Additionally it provides a long term tonic for your lawn and has a definite 'greening' effect. It is normally applied in late spring but where moss is a problem it can also be applied in summer. Apply when the weather is dry but it is liable to rain in the next day or so. Water well if rain does not fall.

Lawn sand works because the powder clings to the rough broad leaf grass and weeds whereas most of it slides off finer grasses. Where the powder clings to vegetation, it severely scorches it causing damage. When the powder enters the soil it stimulates growth and causes the grass to become greener.

Chemical Weed Killer
Some weeds such as dandelion, plantain, hawkweed and buttercups will not be deterred by lawn sand especially if they are well established. In these cases you may want to use a chemical weed killer. There are several varieties on the market and most well-known brands do the job well.

The best time of the year is late spring to early summer when the weeds are showing strong growth. Choose a warm day with little or no wind to apply the treatment. It is important that the leaves of the grass are not wet at the time of treatment because this will dilute the effect. At the same time, the soil beneath the grass should be moist not bone dry. Study the instructions carefully, because some brands recommend that you do not mown the lawn for a few days beforehand.

Wait at least 3 days after application before cutting your lawn again. For most weeds a single application is normally sufficient, but some weeds may need a second application.

Spot Weed Killers
Spot weed killers are useful where the number of weeds is low but they are difficult to remove entirely by digging them out. They come in handy applicators which enable the chemicals to be smeared on the surface of individual weeds or in small spray cans.