Establishing a new lawn that is lush, healthy and largely weed free is
a challenge for any gardener. However, if the right steps and advice are
followed, the end result of producing a new lawn that is easy to maintain
and looks great is well worth the time and effort.
Preparing the soil
A thorough job of preparing the soil is critical to achieving the perfect
lawn. This includes eradicating weeds, drainage, soil pH levels, levelling,
firming/raking, watering and fertilising.
Kill existing turf to eliminate unwanted lawn grasses and perennial weeds,
particularly weeds that have rhizomes or deep tap roots, as they regenerate
rapidly from small pieces of root. Examples are dandelion (Taraxacum
officinale), nut grass (Cyperus rotundus), docks (Rumex
spp.), soursob (Oxalis pes-caprae) and other Oxalis spp.
Initially, apply a broad-spectrum non-residue herbicide such as glyphosate
or essential oils in an ‘organic interceptor’ to eliminate
grass weeds and some broadleaf annual weeds. Plants that survive the first
herbicide application should be eliminated using a selective herbicide.
Drainage is only required on heavy clay soils and can be improved by incorporating
two parts sand to one part soil. However, a drainage system of pipes laid
in a trench, backfilled with gravel is a better alternative. For most
loam soils that receive 600-1000 mm rainfall, one drainpipe every 5-8
m is recommended. Heavier clay soils or sites in areas with rainfall above
1000 mm will require drainpipes laid at closer intervals.
Grasses grow satisfactorily at pH levels of 5.5-7.0. In this pH range,
nutrients required by turf grasses are soluble rather than being bound
up in the soil. Soil pH can be tested using a kit available from garden
centres. For acidic soils (pH less than 5), dig or rotavate lime (calcium
carbonate) into the soil. The recommended rate depends on the starting
pH and soil type (Table 1).
Table 1: Amount of lime (g/m²) required for different soils.
Firming and raking
Tread the soil evenly about three times to firm it. Rake the surface to
provide a fine tilth. Remove stones more than 1 cm in diameter if the
soil is being prepared for sowing, or 2.5 cm in diameter for turfing.
Allow 3-4 weeks for weed seeds to germinate, and treat the area with glyphosate
to kill them.
New turf requires watering at frequent intervals to keep the seed or turf
moist during this initial 2-week growth period until the root systems
develop. Treat the lawn as an established turf after 1 month.
A few days before establishing the lawn, apply a compound granular fertiliser
containing nitrogen (N), phosphate (P) and potassium (K) to the prepared
soil surface at a rate of 150-200 g/m². Rake the fertiliser into
Turf can be applied any time of the year except during hot dry periods.
Lay turf on to a moistened soil surface to encourage root development.
Starting at the edge of the site, lay the first row of turf in a straight
line. Standing on planks placed on the first row, rake over the soil on
which the next row is to be laid. Lay the second row so that the turf
forms an alternate bond, like bricks in a wall. Cut the edges to shape
with a sharp flat or half-moon spade; use the inside of a hose for a curved
edge or a plank for a straight edge. Roll the newly laid turf with a light
roller (50 kg), and brush a top-dressing of sand and soil mix into the
joins between the turf pieces to encourage the roots to spreads into the
gaps. Water the turf thoroughly.
Calculate the amount of seed required by multiplying the size of the area
(m²) by the recommended sowing rate (g seed/m²). Shake the seed
bag to mix the seeds.
If sowing by hand, divide the area into equal sized sections, e.g. 1
m x 1 m, to ensure an even distribution of seed cover. Measure the correct
amount of seed (Table 2) for each section, and scatter half the amount
in one direction and the remainder at right angles. Repeat for each section.
If sowing by machine seed spreader, divide the amount required for the
lawn by half, and sow one half in one direction and the remainder at right
angles to the direction of the first application.
Table 2: Seed sowing rates (g/m²)
Fescues & bents
Perennial ryegrass & other grasses
Bents (Agrostis spp.)
Carpet grass (Axonopus spp.)
Couch grass (Cynodon dactylon)
Centipede grass (Eremochloa ophiuroides)
Red fescue (Festuca rubra rubra)
Perennial ryegrass (Lolium perenne)
Kentucky bluegrass (Poa pratensis)
After sowing, lightly rake over the surface and water with a sprinkler.
Sowing the grass seed at the proper depth (2-4mm) is very important because
the food reserves of the seed (endosperm) may be used up before the new
shoot can reach the soil surface and start making its own food through
the process of photosynthesis. A biodegradable paper can be used to cover
the newly sown seeds to prevent erosion on sloping lawns. The seeds will
germinate 1-2 weeks after sowing.