Lawns – Sowing Lawns and Turfing Lawns
Lawns as Carpets
Most people want a lawn — an expanse of mown grass — in their garden for one or two quite different purposes. One is to make a smooth green carpet on and beside which trees, shrubs and flower beds can be effectively displayed. That is the appearance motive. Some, but fewer, private owners seek a true grass surface for playing such games as tennis, bowls and croquet. These require the finest grasses, cut to 8mm (1/2in) or less and intensively maintained.
Lawns for appearance are our main concern here, and they, by contrast, can be created just as well from a very different breed of stronger-growing grasses. What is odd is that much of the publicity from seed firms presses the virtues of fine grasses for all purposes. Partly, perhaps, this has come about because fine grasses fit the traditional idea of an English lawn; but also, I suspect, it is because they are more profitable in the long run since fine-grassdemand so much more maintenance and expenditure on fertilizers, , etc.
The main lawn grasses on the market are fescues and bent grasses of the Agrostis species, rye grasses and smooth-stemmed meadow grasses. Occasionally other species are used for special purposes, such as wood meadow grass (Poa nemoralis) for shady places and rough-stalked meadow grass (Poa trivialis) where theis damp. Unfortunately neither makes a really good sward and it is really better to correct the unsatisfactory conditions or use something other than grass to surface these awkward places.
Fescues and bent grasses have narrow leaves, stand mowing well and are the main grasses used to create very close smooth turf. They are generally used in mixtures, the bent grasses being more creeping than the fescues and so helping to bind the turf together. They require good drainage and aeration, are not very resistant to weed invasion and must be well cared for.
Perennial rye grass (Lolium perenne) and smooth-stalked meadow grass (Poa pratensis) are much stronger-growing species used a great deal in agriculture; shorter-growing, more freely branching forms have been selected for garden use. They are hard-wearing and have a good green colour but they die out if persistently mown very hard. Both are excellent for lawns, often mixed with Agrostis tenuis. Good selected forms of perennial rye grass are Aberystwyth S23, Aberystwyth S321, Kent Indigenous, Hunter, Manhattan, Pelo and Sprin ter. Recommended forms of smooth-stalked meadow grass are Bensun, Delft and Merion.
WHEN TO SOW AND HOW
Late March to late April and mid-August to late September are the best periods for sowing. Earlier than this the soil is rarely warm enough for germination, while seedling grass from later autumn sowings can be severely damaged by weather, and summer sowings may be held back by dryness, though this can be overcome by watering. Sowing rates are 20-40g per m3 (¾ – 1-1/2oz per sq yd) according to the speed with which complete grass cover is required.
All seed should be sown on soil that has been well broken up and cleared of, if necessary by leaving it fallow for two or three weeks so that weed seeds can germinate and then killing the with a herbicide such as paraquat (Weedol) or (Tumbleweed) which leaves no harmful residue in the soil.
Seedling grass, whether fine or coarse, should not be cut until it is at least 50mm (2in) high and then only to 25mm (1in). Later, when it has started to tiller (produce side growths), cutting can become progressively more severe. It is best not to use selective weedkillers on young grass and in any case all the annual weeds that may appear will automatically disappear with regular mowing. More persistent weeds can be removed by hand or dealt with later. However, if it is decided that some chemical treatment is necessary earlier, ioxynil (Actrilawn) will prove the safest herbicide to use.
A NICE PIECE OF TURF
The conventional way to make lawns from turf is to purchase turves cut from a meadow or from a field in which grass has been specially cultivated for this purpose. The traditional method is to cut strips 90cm (3ft) long, 30cm (1ft) wide and 4-5cm (1-½ – 2in) thick. These long turves are rolled up for transport and convenient stacking on arrival. For some purposes turves 30cm (1ft) square are preferred and these are handled flat.
A fairly new and quite different approach is to sow grass seed on a thin layer (about 20mm / 3/4in) of moist peat spread over fine nylon netting backed by an impermeable sheet which prevents the grass roots growing through into the soil beneath. They do, however, grow through the netting, becoming so firmly enmeshed with it that in a few weeks the turf can be rolled up like a carpet with all the roots intact. As it is being relaid, the backing sheet is stripped off so that the grass can proceed to grow normally into the soil. This kind of turf is much lighter than conventional, soil-grown turf and can be supplied in much larger sizes so that laying time is reduced and there are fewer joins between turves to fill up and knit together. Since it is grown from seed, this can be specially selected for various purposes and the turf should be weed-free.
The best seasons for turfing are the same as those for sowing except that it is more difficult to turf than it is to seed in summer or at any period when the weather is warm and dry. Conventional turves are laid in straight rows with the turves in alternate rows staggered like the bricks in a wall so that they bond together more firmly. The edges of lawns are always laid with full-sized turves; any cutting-down to obtain a perfect fit is done in one of the inner rows.