Lawn Care

A garden lawn is an integral part of almost all gardens and every gardener strives to achieve a lush and healthy one. The following is a brief guide to how to care for your lawn season by season. Horticolour can provide you with advice as to how to maintain your lawn.

Spring and Summer

At this time of year, the lawn is actively growing and requires feeding, moss-killing, weeding and regular mowing. Spring is also a suitable time to over-seed sparse areas.

Mowing is the most obvious (and one of the most important) maintenance task over spring and summer. Regular mowing keeps the lawn in good health.

Moss is a problem in damp, poorly drained lawns. Spring is a good time to remedy moss problems, which occur in damp and poorly drained lawns.

In mid-spring (often late March to April), a proprietary spring or summer lawn fertiliser can be used to feed the lawn. This should be applied at the manufacturer's recommended rates. Feeding the lawn will increase vigour and help prevent weeds and moss from establishing. Fertilisers should be applied when the soil is moist or when rain is forecast. If grass loses its vigour and freshness between late spring and late summer (often May to August), repeat the application of spring or summer lawn fertiliser or apply 15g per sq m (½oz per sq. yd) sulphate of ammonia mixed with four times its weight dry soil to ensure even distribution and to avoid scorching. This should be applied in cool, moist conditions and lightly watered it in. As an organic alternative, use chicken manure pellets. Repeat fertiliser application a third time if needed six to eight weeks later.

Do not apply spring or summer lawn fertilisers, chicken manure pellets or sulphate of ammonia after August because they contain too much nitrogen for autumn use. This encourages green leafy growth at the wrong time of year, when it could be damaged by winter cold or pests and disease.

Watering lawns is not usually necessary because they usually recover well when rains return. However, if you do have to water the lawn and maintain a green sward, water when the soil becomes dry, but before the grass turns yellow or brown. If the ground is very hard, aerate it by spiking with a garden fork before watering, to aid water penetration. Watering once a week to every 10 days is normally sufficient.

Spring is also the time for laying new lawns. After laying turf, the lawn should be left completely unused for the first week. Lawns from seed should be left un-used until their first mowing. Avoid using new lawns heavily in their first season. Newly laid lawns can be fed like established lawns. They need watering, but should not be over watered, as this may result in shallow rooting and poor establishment.

Autumn

Autumn is the time to examine lawns for signs of summer wear-and-tear, and treat if necessary. At this time of year, any treatment has time to take effect before temperatures fall and growth stops. Any treatment is best carried out during September, when there is time for the grass to respond before the soil temperatures fall and growth stops for the season.

At this time of year, the following tasks may be required:

1.Scarifying

This involves regular raking, or scarifying, the lawn to keep levels of thatch under control. Layers of thatch greater than 1cm (3/8in) deep can prevent water and fertiliser being absorbed. To remove thatch, rake vigorously but carefully with a spring-tined rake. For larger areas powered tools are available as single units or mower attachments. However, exercise caution when doing this as the turf can be damaged with vigorous raking.

2. Aerating (spiking)

Aerating (or spiking) lawns allows air and water to travel to the root zone. A lawn with good aeration will be better able to cope during drought or water logging. For an average lawn, aeration every two to three years should be adequate. Concentrate on areas that receive the most wear and those that are compacted. Small areas can be spiked with a garden fork, spacing holes 10-15cm (4-6in) apart and deep. On clay or waterlogged soils use a hollow-tine aerator every three to four years. This extracts plugs of soil from the lawn. Hand held and motorized hollow tiners are available. After hollow-tining, sweep up the plugs and then rake a top-dressing into the holes to improve air and moisture penetration.

3. Top-dressing

Top-dressing is the application of loam, sand and well-rotted organic matter to a lawn in order to correct surface irregularities and improve the texture of difficult soils. This encourages greater rooting and thickening of turf. The top-dressing mix is three parts sandy loam, six parts sharp sand and one part compost or leaf mould.

4. Flattening

Lawns can develop bumps and troughs so use an edging iron or spade to slice through the turf and roll it back. Fork over the underlying ground and add or remove soil as needed. Replace the turf, pressing the edges together, and water thoroughly.

5. Problems

Lawns can suffer from a variety of fungal problems and autumn is a good time to repair damage caused by fungal diseases or pests.

Drought

Healthy, well-maintained lawns are best equipped to deal with drought conditions so always try to keep your lawn in tip top condition! In times of severe drought, lawns can turn brown and even stop growing. However, this is usually only superficial as most lawns will recover as soon as the rains come. Ornamental lawns of fine bent-type grasses are most likely to suffer when water is in short supply, whereas general garden lawns containing fescue grasses may be better able to cope.

However, in extended periods of drought, or where the lawn is not well maintained, lawn grasses can become weakened and their roots deteriorate. If the grass becomes thin, weeds and moss easily establish with the onset of autumn rains and action may be necessary.

When mowing during drought, raise the height of cut to avoid weakening the grasses and allow the clippings to remain on the surface to act as a mulch and retain water. Make sure the clippings are small, or they will smother the grass and cause damage.

If watering is required, for example with ornamental or newly laid lawns, water once the soil becomes dry but before the grass changes colour. If the ground is very hard, aerate it by spiking with a garden fork before watering, to aid water penetration. Water in early morning, evening or even night-time, to reduce water wastage from evaporation. Watering once every seven to 10 days is normally sufficient. It is important not to apply too much water as this encourages shallow rooting of the grass and promotes moss and turf diseases. Excessive watering can also make the lawn more susceptible to drought.

After a period of drought, the lawn will need a thorough assessment to check for any damage. Carry out any renovations needed but do not use lawn weed-killer until the following spring when the lawn will have recovered.

Mowing

All lawns need mowing and is probably the most important job to do! Getting the cutting height and mowing frequency right can make a huge difference to the health of the lawn.

When to mow

Mowing is carried out mainly between March and October. During the summer months, mowing is best done twice a week or once a week during drought. Over spring and autumn mowing can be done once a week and in winter mowing is not usually needed.

Dry and shady areas under trees may need less frequent mowing than areas in full sun with good moisture levels.

Never mow wet or frosty grass, as this can damage the turf and compact the soil. Wait until later in the day when the lawn has dried out or defrosted, or postpone mowing to another day.

Mowing Heights

For the first mowing in spring, set the cutting height to the highest setting. Thereafter, gradually reduce the height of cut until the desired height is reached. For fine lawns, this will be 6-13mm (¼-½in). For ordinary ornamental lawns this will be 13-25mm (½-1in) in summer and up to 40mm (1.5in) in spring and autumn. Avoid excessively close mowing, as this can weaken the grass and encourage shallow rooting. Extremely low cutting may scalp the lawn, leaving bare patches where there are bumps or tree roots protruding above the surface.

If you are unsure of what height to use, the general guideline is never remove more than one-third of the leaf shoots in any one mow.

Weeds

Just like other areas in the garden, weeds can invade the lawn. Lawn weeds usually include clover and dandelions, coarse-leaved grasses, daisies and buttercups. Early identification and prompt removal can alleviate large-scale problems. This can be as simple as following a yearly lawn maintenance plan. Lawn weeds establish because they survive close, regular mowing. They spread by seed or creeping stems, and are usually problematic where the grass is sparse.

Non-chemical controls

• Feeding, aerating and scarifying will encourage the grass to be more vigorous and so make it more difficult for the weeds to compete.
• Remove rosette-type weeds, such as dandelion, daisy and plantain, with a hand fork.
• Dig out weeds resistant to weedkillers in autumn; and re-turf or re-seed.
• Rake over and then mow to discourage creeping weeds such as speedwells, white clover, silverweed and sorrels.
• Apply garden lime to acid soils in the winter. Dress with 50g per sq m (1½oz per sq yd) to deter weeds such as sorrels and field woodrush.
• Avoid close mowing as this can weaken the grass and allow the weeds in.

Chemical Controls

Lawn weedkillers may be needed where many weeds have established. When buying a lawn weedkiller, check the label to find out if it will work on the weeds in your turf. Apply a weedkiller in a spring and summer, when the grass and weeds are growing vigorously.

It is important to read and follow all instructions when using chemicals. Choose a product that is easy to apply. Lawn weedkillers are available to spray on, apply with watering can and dribble bar, and as granules that are scattered on the surface. For spot treatment, apply ready-to-use sprays. Only use with a combined mosskiller where moss is a problem. Most lawn weeds are killed by weedkiller application, some by a single treatment, but others requiring two or three applications at four to six week intervals.

New lawns are often severely damaged by weedkillers if applied to lawns within six months of sowing or turf-laying.

Moss

Most gardeners have trouble at some stage with moss on lawns. This is unsightly and is often a result of poor growing conditions. By improving the health of the lawn, moss can be kept at bay. Moss can be a temporary problem following drought or waterlogging, or more persistent, suggesting a problem with underlying conditions. On new lawns this may be due to poor site preparation. On established lawns poor vigour, acidic soil conditions, a lack of feed, insufficient aeration, poor drainage, shade, close mowing and over-use are likely to blame.

Killing and removing the moss is just the start. To remain moss-free, the vigour of the grass must be improved and any other contributory factors addressed. Good autumn lawn maintenance is essential to maintaining lawn health.

There are several types of moss that grow on lawns. These are usually coarse, loose, green or yellowish-green tufts between the grass, but can form densely matted tufts or, in the case of Polystichum, appear like small forests of miniature Christmas trees. Moss gives the turf an uneven colour and surface. Loose mosses make the lawn feel spongy to walk on.

Cause

Poor growing conditions favour the growth of moss in lawns. These might include:

• Sparse grass cover
• Worn areas of turf, especially along walkways and where children play
• Shady areas, especially beneath trees
• Compacted soil
• Wet weather and waterlogged conditions
• Drought-stressed grass
• Mowing too close
• Impoverished lawns or infertile soil
• Poorly prepared or poorly maintained lawns
• Acidic soil conditions

Non-chemical control

Scarification: Remove loose moss in autumn, by scarification (vigorous raking). On small lawns this can be done by hand, raking out the moss with a spring-tine rake, but on larger lawns mechanical scarifiers can be hired.

Chemical control

For moss control use a proprietary product, such as those based on ferrous sulphate (sulphate of iron) in spring or early autumn. When the moss blackens after two or three weeks use a spring-tine rake to remove it. The dead moss can be added to the compost heap. The ready-to-use formulations of ferrous sulphate can be used to spot treat small patches of moss on lawns. Mosskillers combined with a fertiliser (nitrogen, phosphorous or potassium, indicated by the abbreviations NPK) are beneficial where grass vigour is low. Apply mosskillers either by hand or with a push-along spreader. Be careful not to apply lawn sand (ferrous sulphate mixed with a carrier) at too high a rate as this can blacken and kill the grass as well as the moss. Apply lawn mosskillers in fine weather. Some require watering after 48 hours if there has been no rain. Check pack for details. Control with a mosskiller will only be temporary unless the conditions which allowed the moss to become established are improved.