Grass is one of the most labor-intensive plants that is grown in the garden. It is quite a good plan to grass over a new garden as the mowing keeps away an invasion of weeds, but as the garden develops it usually replaced with trees, shrubs and perennial plants. There is nothing better to show off a shrub or perennial border than a foreground of grass.
When reducing the grassed area, start with the awkward corners and work outwards. A good way to achieve the outline of the area to be removed is to cut the grass leaving all the inconvenient spots and these are then converted to beds. To further reduce the time taken to cut the grass, a mowing strip of paving around the edge is a great help, the wheel of the mower runs along it and there is no trimming.
Before sowing any seed or laying turf the area should be thoroughly prepared. It’s best to start this operation as soon as the ground is dry enough to cultivate and if possible allow a period of fallow before sowing or laying the grass. This allows any remaining perennial roots to sprout and weed seeds turned up during digging to germinate, so that they can be killed off. Repeat the process a few times to give the new grass the best chance to grow uninhibited and reduce the development of a weedy sward later. If sowing seed the best times to ensure even germination are in April or early May, and late August or September, but with the sort of weather we have been having lately, there will probably be enough rain throughout the summer. Turf can be laid at most times of the year except during frost or drought.
The site will probably need a certain amount of leveling depending on the finish required. For a formal lawn it should be reasonably flat and the humps will have to be removed. Shallow bumps and dips will be sorted while digging, but large changes in levels that are deeper than the topsoil layer will require a bit of engineering. The soil will have to be removed and the subsoil moved around to the required level before the topsoil is replaced.
Check to see if there are any drainage problems, soggy areas will need some sort of treatment to give a satisfactory lawn. The Victorians used to remove all of the topsoil and lay a layer of cinders or gravel before replacing it. This may be an elaborate solution and is the method used when preparing playing fields and putting greens to-day. A small drain filled with stones may be enough to lead the water away. If there is no outlet to allow it to drain from the site, a soak away consisting of a pit filled with more stones should cope with any water which collects.
With the levels and drainage sorted, fork over the soil removing all perennial weeds with their roots. If they are dense the best thing is to skim off the surface first and any remaining roots will be found when digging. In a large area the skimming and digging can be done with hired mechanical equipment, but the advantage of hand digging is that you can be more thorough in finding roots and stones. Any stones larger than 25mm in diameter should be removed; this will become an obvious step if you later try to spike the lawn. They can be used to form the base of a path or to fill a drain. The soil will be loose and full of air pockets, these need to be compacted otherwise later settlement will result in a bumpy finish. This is usually achieved by tramping the whole surface, putting the weight on the heels and shuffling back and forth. Onlookers may find it amusing, but this a tried and tested technique. When the compacting is complete rake to a smooth finish, filling small dents and removing debris to produce a seed bed or to be ready for laying turves.
When sowing seed measure out the required amount, split it in two, sowing half in one direction and half at right angles. This should result in a more even spread of the seed. The rate of sowing is about 30 to 45g (1 to 1.5oz) per square metre; do not leave dense clumps as this can lead to damping off. Roughly speaking this is a handful to 2 square metres in each direction, hold your closed hand, fingers upward at waist height, and shake in a circular motion allowing the seed to fall out. Rake gently – a spring-tined rake used upside down works well. Deter birds with carrier bags tied to canes placed around the area.
When germination begins the seedbed should not be allowed to dry out, so use a fine spray or sprinkler to keep it damp – avoid water logging as the seed will rot. When it has grown to about 50mm it should be rolled to settle in the roots and encourage tillering – some species of grass grow side shoots which root and thicken the sward. Use the roller of a mower with the blades tipped up or hire one as this is probably the only time you will ever need it. When the grass stands up again it can be lightly trimmed at the highest setting of the mower.
Most of the turves sold at garden centres contain mainly Rye-grass so are only suitable for a utility lawn, for a finer finish you will have to find a specialist grower. When choosing the turf unroll it first to check that it is recently cut – ie. no yellowing blades of grass. Also the root system should be mature enough to hold together if you give it a tug, otherwise it will fall apart as it is laid.
For a perfect bowling-green finish, a mixture of fine grasses must be planted and when established it will have to be mowed two or three times per week during the growing season. Frequent close cutting thickens the sward leaving no room for weeds to grow. The lowest height of the ‘luxury lawn’ in summer, should be about 13mm (½ inch), in spring, autumn and during drought periods the height should be about 19mm (¾ inch).
A less formal grassed area can have some of the ‘weed’ grasses like Rye-grass, and a few broad leaved weeds are allowed as well. Cutting this ‘utility lawn’ too short will weaken the coarser grasses, allowing low growing weeds and moss to thrive. The frequency of mowing is every 5 to 7 days.
You can relax the keeping of grass even further and have a wildflower ‘meadow’ effect by reducing the fertility and allowing the grass to grow naturally. A number of wildflower species are included and cutting is only required once in the late summer to allow the annual seeds to fall and germinate for the following year. If a patch of grass has been mown (removing the cuttings) and unfertilized for a long period, it will be pale and weeds will have invaded. By digging out the more invasive weeds like Creeping Buttercups it should have the potential to become a ‘meadow’ area. It is difficult for the wild flowers to establish from seed so they are usually introduced in the form of plug plants, either bought-in or raised in trays.
One of the certainties in gardening is that weeds will appear among the grass at some time. The definition of a weed is down to the gardener – from rampant Creeping Buttercups, for the average gardener; to an unwelcome species of grass, for the purist. They invade by numerous methods.
Seeds are carried by the wind, on foot, in un sterilized top-dressings and by birds.
They can already be present when the ‘lawn’ is made and if ignored will spread.
Some of the perennial weeds like Clover and Daises form dense mats by creeping around.
Mowing, particularly with a rotary mower, can spread segments of stem and seeds which take root.
Moss is ever-present as it’s spores are carried in the wind and rain, and our temperate climate provides ideal growing conditions.
Removing weeds depends on their density, the size of the lawn and the preferences of the gardener. a small number of isolated weeds can be uprooted with the tine of a fork or spot-weeded with a weed killer. A large number are best treated with a selective weed killer.
Maintaining a healthy lawn requires a number of tasks to be carried out regularly apart from the mowing. Foot traffic compacts the soil cutting off the air which is essential for healthy roots.
Spiking is the remedy and involves inserting the tines of a fork to about 10 cm and gently levering back and forth. To keep the holes open, coarse sand can be swept across the surface. Also a layer of dead grass or thatch tends to build up choking the sward and is removed by scarifying.