Weeds and weeding

No matter how good the preparation of the site, some weeds will almost always appear. This is not the fault of the lawn seed. Weed seed lie dormant in the soil for a long time and tests undertaken by research establishments have shown that a cubic foot of topsoil can contain many thousands of weed seeds. Weed seeds are also carried by the wind, birds and even on the soles of your shoes.

The preparation of the seedbed creates the ideal germination conditions for weed seeds. As they are brought to the surface they will grow along with the newly sown lawn seed.

It is desirable to leave the seedbed for your new lawn to lie fallow for the summer if possible for this will give many weed seeds lying near the surface of the seedbed a chance to germinate and be destroyed before the lawn seed is sown. If you hoe the seedbed in the period do not disturb the soil deeper than 4cc (1.5 inches).

Many of the weeds that will appear in a new lawn will be annual weeds and will disappear with mowing. Others that persist can be treated with a proprietary selective weed-killer after three months of growth. If desired, they can be treated before the three months are up but, in this case, only with a herbicide specially formulated for use on new lawns.

When applying a weed-killer always follow the manufacturer's instructions precisely, especially so in the case of newly sown lawns, otherwise the young grass may be damaged.

While your new lawn is in its early growth stage, weeds may be pulled out by hand but, if this is done, take great care not to disturb the surrounding grass seedlings. You can also cut the weeds out with a sharp pointed knife.

Established lawns can be treated with weed-killer any time from May to September but not during periods of drought, as the weed-killer will not be effective and may scorch the lawn.

Weeds and other undesirable intruders can be broken down into four main categories:

Annual weeds
These are mostly apparent in newly sown lawns and usually disappear with mowing. Examples of annual weeds are Groundsel, Chickweed, Shepherds Purse, Hen and annual Black Nettle.

Perennial weeds
These appear in all lawns and often will not disappear with mowing but will have to be treated with a weed-killer. Examples of perennial weeds are Dandelion, Dock, Daisy, Plantain and Buttercup. Some perennial weeds such as Clover, Pearlwort, Trefoil and Yarrow are more resistant to treatment and may require two or more applications.

Coarse Weed Grasses
These cannot be eradicated by selective weed-killers as they have the same characteristics as the proper lawn grasses. The only effective way of getting rid of them is to cut out the roots with a sharp pointed knife. Always try and remove weed grass before it becomes too established. Examples of coarse weed grasses are Yorkshire Fog, Creeping Softgrass and Cocksfoot, all of which grow wild in great abundance, this seed being spread by wind and birds.

Moss
This is usually the biggest problem of all and can be caused by a number of factors. Lack of fertiliser, mowing too close, poor drainage, shade and dripping from tree, over-rolling, compaction, lime shortage, too little topsoil … all these are reasons why moss may invade your lawn. A proprietary brand of lawn moss killer will check the spread but to get rid of moss you must first find out which of the above factors are causing the occurrence and rectify the matter.