Lawns
To locate images associated with this article please visit our
image collection at Country, Farm and Garden Photo Library
When laying out a new grass lawn you have
the choice of growing from seed or laying turf. Sowing from seed allows you to
make your choice of grass types and their proportions but laying turf provides
an instant effect. The purist would probably always opt for seed but for small
lawns the speed and convenience of turf is hard to ignore. Turfing is expensive
and for areas over 100 m style='font-size:8.0pt;
mso-bidi-font-size:10.0pt'>2 this may be
prohibitive.
Preparation
Whether you choose seed or turf
preparation is all important. The best time to establish a new lawn is spring
or early autumn but start early to allow ample time for preparation.
The site should be levelled or if on
sloping or mounded ground the most severe slopes and mounds must be reduced or
they will be ‘scalped’ every time the lawn is mowed. The more level the lawn
the easier it will be to mow.
The surface should be raked, clods broken
and any stones removed. Spraying the area with a glyphosate weedkiller will
ensure that the grass does not face too much competition on germination but a
certain amount of weed will always come up with new grass or in the joins
between turf rolls.
Some gardeners like to use a roller to
eliminate small humps and hollows but others feel that rollers cause too much
soil compaction. I prefer to use a roller if sowing a top quality lawn with
fine seed but it is not really necessary when sowing a coarse seed or laying
turf.
If you have allowed sufficient time it’s
a good idea to sprinkle some lawn fertiliser over the area about a week before
sowing. You need to allow this amount of lead time to allow the fertiliser to
work into the soil. The young seedlings or turf roots may burn otherwise.
Carefully consider the drainage of the
site. If possible a gentle slope to a corner where a drain is located is best
but otherwise just make sure there are no moisture
gathering hollows. If the site is known to be poorly drained the time and
expense of laying drains is well worthwhile.
Lawns from seed
Your choice of seed will depend on the
lawn’s intended use. The traditional blend of brown top and chewings fescue is
probably still the best choice for top quality turf but there are many new
varieties and blends on the market. Extensive turf research in recent years has
led to these new strains and they promise to make turf maintenance considerably
more straightforward.
Unless you are sowing an area that will
be subject to considerable abuse avoid using coarse rye grasses or overly
aggressive growers, such as kikuyu.
Smoothing and levelling is most important
when sowing from seed. After the initial clearing and raking attach a 1-1.5 m
board to your rake head and use it to screed off the surface. Rolling or
stamping over the surface will help to consolidate the loose surface material
that the raking and screeding brings up. Do not use a roller on wet ground as
the soil will stick to roller and make a terrible mess.
Once you have the surface smooth and even
it’s time to sow. Do not be too concerned about the positioning of lawn edges
and garden beds at this stage, it’s more important to get an even grass cover.
Any design changes are best done after the lawn is established.
Immediately prior to sowing lightly rake
over the surface. This will give the seed a layer of slightly loose soil to
‘key’ into and will prevent it being blown away before germinating. Sow the
seed in strips or blocks to ensure even distribution. Going over lightly twice
usually gives a more even spread than trying to do it all at once.
After sowing lightly rake the surface
again. This mixes the seed into the loosened crust, you don’t want to bury it,
just blend it with the surface tilth. Water the surface very gently to avoid
any puddling or run off.
Even with treated seed you may need to
take precautions against birds eating the seed. If you know this is going to be
a problem put in the pegs for attaching nets or strings before sowing. Keeping
the surface slightly moist should discourage the birds from using your new lawn
as a dust-bathing area.
In mild weather the seed will germinate
rapidly. Watch out for areas of patchy germination and oversow if necessary.
Keep the surface moist but err on the dry side; overwatering can cause fungus
diseases to take hold, especially in warm humid weather.
Within two to three weeks the lawn should
be ready for its first mowing. Set the blades high and avoid any sharp turns
that may cause the wheel or rollers of the mower to cut into the surface.
Even before the first mowing you will
probably begin to see signs of various turf weeds in the lawn. Many weeds will
be killed off by repeated mowing but some will take hold if allowed. Modern
grass strains are effective at choking out weeds but you may still need to use
selective broadleaf weedkillers when establishing a new lawn.
In southern areas spring is undoubtedly
the best time to establish new lawns but in many North Island and
coastal areas autumn sowing produces better results. If you are unsure of your
local conditions make enquiries at a garden centre or contact one of the
agricultural universities.
Lawns from turf
Turf can be laid at almost any time but
spring and autumn are still the preferred seasons. Prepare the site well in
advance and have everything ready for laying as soon
as the turf arrives. It will keep for several days if left rolled up and moist
but is best laid right away.
To avoid have rows of matching joins use
an overlap method similar to that used for brick laying (see illustration). It
is best to extend the turf out beyond the intended lawn area and cut it back
rather than to fill in around the edges with offcuts.
Butt each strip up tightly against the
other and press down using a board attached to a rake head. Once the turf is
laid top-dress the surface and fill any cracks with a 2 to 1 mixture of sand
and fine soil (or peat). Spread this using the back of a rake or a screeding
board.
Keep the fresh turf moist and mow as you
would an established lawn. Watch out for weed growing in the joins between
turfs and any dead patches that may develop.
Rugged grasses
In some areas, particularly those that
are hot and humid, yet dry, in summer the traditional lawn grasses tend to be
difficult to maintain. In such areas the stoloniferous grasses, such as kikuyu
and buffalo grass are sometimes used. These are established by planting runners
that eventually grow to form a mat.
While these grasses have some appeal in
tough climates they tend to be very invasive so should not be used near flower
beds or other areas of loose soil in which they can easily spread.
The new grass blend that are becoming
prominent should go a long way to eliminating the need to use such potentially
invasive species. If you have found these grasses to be the best option in the
past it may pay to check out the new introductions rather than just planting
kikuyu out of habit.
Alternative lawns
Grass is not the only the way to lay a
lawn, there are alternatives. However, few of these are as easy to establish
and maintain as grass and none are capable of producing a top quality sward.
Dichondra micrantha (repens)
Mercury Bay weed is popular in some areas. It does best in a mild climate and
may be established either by sowing seed or planting ‘plugs’ (every 15-30 cm)
that eventually grow together. Dichondra
needs plenty of water and feeding to be at its best but is a good choice where
excess humidity makes lawn establishment difficult.
Cotula squalida
A popular choice for
bowling greens and areas where the surface must be closely cropped but traffic
levels are high. Although seldom used for
domestic lawns it could be. The drawbacks are that it needs regular mowing,
watering and feeding and some gardeners find the red colour unappealing.
Chamomile
Has a feathery appearance and the low growing forms (particularly the
non flowering ‘Treneague’ can be used to make an informal lawn. Chamomile will
not withstand heavy traffic and will not thrive in damp or shady areas.
Ground cover thymes
Can make effective lawn substitutes but
they will not withstand regular traffic. There flowers are very popular with
bees so avoid standing on thyme with bare feet. Also very
attractive to butterflies, which can create a beautiful effect on a warm spring
day. Thyme does not do well in damp or shady areas.
Few lawn grasses or
traditional substitutes do well in cool moist positions but there are a couple
of low spreading plants that can be used as small scale lawn substitutes.
Mentha requienii
Corsican mint is small spreading plant
with bright green leaves. It has a delightful creme de menthe scent when
crushed and will withstand light traffic and occasional mowing.
Soleirolia
soleirolii
Baby’s tears looks very similar to Corsican mint but lacks the fragrance. It may be
killed back by hard frosts but usually shoots away in spring. The silver
variegated form is attractive but tends to revert to green. Irish moss (Arenaria and Sagina species) is another alternative for shady areas,
it is available in green or golden forms.
Lawn maintenance
Although the weekend lawn mower symphony
is something of a suburban cliche lawns require
considerably less maintenance than many other parts of the garden.
Mowing is the most obvious task. In warm
moist weather it will need to be done once a week but fortnightly is regular
enough for most of the year. In many areas winter mowing is unnecessary. Resist
the urge to cut closely to increase the time between mows. Cropping too closely
will reduce the vigour of the grass and may lead to ‘scalped’
bare patches.
Lawn mowers
There are two main styles of lawn mower,
the rotary and the reel, or cylinder. Rotary mowers are the most popular
because they are rugged and require little maintenance but the quality of their
cut leaves much to be desired. Rotary mowers are all motor powered,
either electric or combustion. Most rotaries are wheeled but some are designed
to hover just above the surface, the wheels may be motor driven.
Reel mowers are available in manual or
motorised designs. Hand mowers are effective for small areas and are quiet and
pollution free but they are tiring to use for long periods. The cut quality of
a hand mower is not as good as the motorised models because of the weight
restrictions that hand pushing impose.
Motorised reel mowers may be electric or
combustion engine driven. For large lawns the petrol motor is the best choice.
The even cut and the striping effect of the motorised reel mower makes it the
first choice for fine lawns.
Very large lawns may necessitate a
ride-on mower. These come in rotary or reel styles. Ride-on rotaries are
reasonably inexpensive but ride-on reel mowers are generally the preserve of
golf courses and top class sports fields. Towed gang mowers are another
alternative for very large areas.
Whichever mower you choose it’s best to
use the grass catcher. The so-called mulching mowers are suitable for
occasional use but they tend to eventually lead to a hard crust forming on the
lawn.
Fertilising and weeding
Like any other plant lawn grass needs
feeding. Spring and autumn are the recommended times but regular feeding
throughout the year is beneficial. Some lawn feeds incorporate broadleaf
weedkillers so the two jobs are done at once.
Some lawn feeds will also help to kill
moss. Iron sulphate will rapidly blacken off and kill moss if applied dry and
left for a few hours before watering in. The grass may blacken too but will
rapidly recover.
In most cases proprietary lawn
fertilisers and weedkillers will be quite satisfactory and safe provided the
directions are followed.
In many cases the lawn will be showing
bare patches after the rigours of summer. An autumn top-dressing with a 2-1
mixture of river sand and fine soil with added fertiliser and grass seed will
rejuvenate a tired lawn.
Aeration
This is an important aspect of lawn
maintenance that is often overlooked. Regular mowing and other traffic compacts
the soil and starves the grass roots of oxygen. Many a bare patch that has been
put down to grass grub is actually due to poor aeration and soil compaction.
A lawn should be aerated at least once a
year; the best time is mid to late autumn. The ideal
method is a coring machine as used on golf greens but these are unavailable to
most gardeners. A practical alternative is to go over the lawn with a fork,
driving it straight into the ground as deeply as possible at regular intervals.
Apply fertiliser and top-dress if necessary after aerating.
While worm casts may be unsightly and may
leave muddy patches on the lawn it’s important to remember that the worms are
aerating the lawn. Don’t kill the worms.
Pests
Beetle and moth larvae can devastate a lawn. Most of the time birds will keep them under control but in severe cases chemical methods may be required. The usual method is to sprinkle insecticide granules over the lawn then wash them in. This will also kill the worms so use only as a last resort.
Copyright Geoff Bryant
|
