In the last lesson we looked at How to Sow Grass Seed. Today we will look at creating an instant lawn using turf or sod. Weather you call new grass Sod or Turf, the method of laying it is pretty much universal.
For turf/sod to flourish and produce a successful lawn, good soil preparation is paramount and if possible the ground should be prepared a few weeks beforehand to allow for settlement. It is equally important to purchase good, weed-free grass that are of the same thickness and have them delivered as near as possible to the date you intend to lay them. If they arrive 48 hours before laying, stack them without unrolling; if there is to be a longer gap between arrival and turfing, unroll each role and lay it flat.
Marking out curved edges
There has, in recent years, been a breakaway from the traditional square or rectangular lawn in favour of ones with gently curving edges. An irregular lawn site is a bit more difficult to mark out, but the easiest method is to lay out a length of string or rope to mark the outline, then drive in canes or wooden pegs against the string at intervals of about 60-90cm (2-3 ft), and twist the string around them. You will then have quite a durable outline of the lawn to which you can work.
Preparing the site
Thoroughly dig the lawn site to the depth of a spade (single-digging), or, if the subsoil (lower soil) is compacted, to two depths of the spade (double-digging). Be careful not to mix subsoil and topsoil -keep them in their correct layers. A hard subsoil could result in a badly drained or waterlogged lawn if it is not well broken up. During digging incorporate plenty of bulky organic matter in the bottom of each trench, such as well-rotted farmyard manure, garden compost, leaf mould, peat, spent hops or even decomposed straw. This will help to retain moisture in light, sandy or chalky soil during dry weather and will encourage better drainage of surplus water in heavy clay soils.
If you have such a heavy clay soil it would be advisable to incorporate plenty of coarse sand or grit during digging to assist further in drainage of surplus moisture. A good lawn can never be achieved if the soil holds too much water in the winter. If your site does become very seriously waterlogged in winter, the only satisfactory answer is to have a proper drainage system installed, consisting of tile drains sloping into a soakaway.
Levelling and raking
Once you have completed digging it is best to allow the soil to settle naturally for a few weeks. This is a good time to carry out any general levelling that may be necessary. Then, shortly before laying the turf, final preparations can be undertaken, when the surface of the soil is reasonably dry. Never work on the site when it is wet and sticky or you will end up with a mud patch.
Break down the roughly dug soil with a fork or rake to produce a reasonably fine surface. Then firm the soil by treading systematically over the entire site with as much weight as possible on your heels. At this stage you may apply a general-purpose fertilizer or sterilized bone meal at 135g per sq m (4 oz per sq yd.), which can be incorporated into the surface during final raking.
This raking is to provide a fine, level surface on which to lay the turf, and you should take this opportunity to ensure the site is really level, with no hollows or
bumps. Rake the soil from any high spots into the hollows and firm it well with your heels. The smoother and more level the site, the better the finished job will be.
Laying the turfs
The actual turfing should be done when the surface is reasonably dry. If you have a paved area with a straight edge, this is a good place to start. Lay one row of turfs along, and hard up to, this straight edge. The turfs will generally be 30cm x lm (12 in x 3 ft) and should be laid lengthways across the site. Allow the turf to overlap your string outline so that when you finish laying you can go round the edges with a knife or half-moon edging iron, cutting them to the required shape, using the string as a guide.
When laying the second row of turfs remember that the joints should be
bonded or staggered like bricks in a wall. In other words, the joints of the second row should fall in the centre of each turf in the first row. You should always work over the turf which has already been laid, so it is advisable to stand on a plank to stop your heels sinking into the new turf, especially if it is fairly moist.
Butt the turfs hard up against each other so there are no gaps in the joints. You can push them close together with the tines of a fork used back to front. If the turfs have been well cut and are all of the same thickness they will require little firming. Patting them down with the back of the fork is generally sufficient. If levelling is necessary, do it by adding or removing soil beneath the turfs during laying. Continue turfing the whole site in this way, ensuring that all joints are staggered. To achieve this bonded effect you will need to cut some of the turfs in half at the edges of the lawn.
After turfing, the lawn can be given a light roll if you have a small garden roller. If not, walk up and down the plank, moving this evenly so that the whole lawn is covered eventually.
Adding a top dressing For a really good finish, brush in a top dressing with a stiff broom. This can be either good, fine topsoil or a mixture of topsoil, coarse sand and fine peat. Apply a 13mm (£ in) layer over the lawn and work it really well into the grass and joints. Remove any surplus, to ensure the grass is not smothered.
In mid spring it will probably not be necessary to water the turfs after laying as the ground should be moist. But as late spring and early summer approach, with drier weather, you must undertake a regular watering programme. If the turfs are allowed to dry out before they become established or well rooted into the soil, they will shrink and the joints will open up, producing ugly cracks. In addition, the turf will take a long time to become established if it is not watered during dry spells in the spring and summer and it is quite likely the grass will turn brown. It will take a considerable time to recover from this, and weeds may start invading the dried-out patches.