Function of lawns

Structure of a lawn

A lawn is made up of several layers:

It is important to prepare each layer properly when constructing a lawn so that the lawn is hard-wearing, does not become covered in moss and weeds and does not become waterlogged or die from drought.

Grass species and cultivars

Wackymacs Wikipedia / CC BY-SA

Terminology:

Blade = grass plant leaf

Tiller = side shoot

Crown = the swollen base of the plant where the leaves connect to the roots

Stolon = a runner which grows on top of the soil surface and sends up young grass plants

Rhizome = a runner which grows under the soil surface and sends up young grass plants

Root system = a grass plant’s roots

Just like other plants, there are many species and cultivars of grass.

Different types of grass have different characteristics:

• different leaf sizes and widths
• different leaf colours
• some gasses form dense clumps and others spread thinly over a large area
• different grasses flower at different times
• different grasses prefer different growing conditions e.g. some like wetter soils, some prefer dry, some like full sun whilst others prefer shade

Seed mixtures

Companies that supply grass seed make up different mixes which contain different species and cultivars of grasses which are suited to different uses and different growing conditions:

• The grass mixes used for animal grazing are different from those used for lawns and sports fields.
• The grass mixes for shady lawns are different to sunny lawns, or wet or dry lawns.

Lawn construction

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The techniques used to construct lawns differ depending on their use and the types of grass that are going to be used. The construction of a bowling green which requires very short grass and an absolutely level surface is more complicated, expensive and labour intensive that the construction of a garden lawn.

When planning the construction of a lawn the following should be considered:

• What type of soil is currently on the area? How deep is it?
• What are the current drainage conditions?
• What is the aspect of the area? How much sun/shade does it get?
• What is the annual rainfall of the area? (Drainage for lawns on the west coast of Scotland is a much more serious undertaking than drainage for lawns on the east coast!)
• What is the lawn going to be used for?

Once all those questions have been answered a suitable construction plan and quote can be written.

Drainage

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Most lawns which are constructed in Scotland require some form of drainage.

If a lawn area is being constructed from scratch then an ideal drainage solution is to lay a free draining sub-base. This means that the whole lawn area has a continuous drain underneath it.

Sub-base drainage:

This type of drainage system works well for clay or peat soils. In areas of very high rainfall, the soil layer can be made from half soil and half sand to improve the drainage further. In drier areas, some organic matter may be included in the soil layer to retain water in drought conditions.

French drains:

This is a system of laying perforated pipes into trenches which are dug into the sub-base and filled with gravel. They work effectively for sandy and loamy soils but not for peat or clay soils because the water doesn’t flow quickly enough through the soil between the drains which means you get stripes of wetter and drier areas and an uneven lawn surface.

Topsoil

Establishing seed

Establishing turf

Lawn care

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Once a lawn has been constructed it is important to provide aftercare and maintenance so that the grass plants establish well, sending roots well out into the soil and thickening up to provide an even green surface. Some maintenance procedures, such as mowing need to be carried out weekly or even more often in the summer and others are annual jobs like top dressing.

Lawns in drier areas or lawns laid on sandy soils may need an irrigation system.

Mowing

Grass plants grow from the base, pushing the leaves up from the crown which is at soil level. If the leaves are regularly chopped off by mowing then this prevents the grass plant from growing tall and then producing flowers and it also encourages the plant to produce more tillers (side shoots). A grass plant with lots of tillers forms a clump which thickens the lawn, covering the soil.

Regular mowing is key to a good quality of lawn and there is a wide range of lawnmowers available which are described on the following pages.

Push reel mower or hand-propelled mowers

This type of mower does not have an engine, the cutting mechanism is put in motion by the user pushing the mower along.

Pros:

• No electrical connection required
• No fuel required
• Little maintenance required
• Compact size = easy storage
• Few moving parts and no engine to break down
• Quiet

Cons:

• Does not collect the grass
• Does not cut the grass into small pieces (mulch) so longer grass may require raking up after cutting
• Hard work to push cut large lawn areas
• May take several passes to properly cut an area

Cylinder mowers

Cylinder mowers have a similar blade arrangement to the push reel mowers in that the blades are arranged around a turning cylinder, but they are powered by an electric or petrol engine. This type of mower is used on golf course greens, bowling greens and formal lawns.

Pros:

• Creates stripes by laying the grass down which can be desirable for formal lawns
• Can cut grass very short
• Cuts the grass into small pieces and mulches them back down into the grass which feeds the lawn

Cons:

• Doesn’t cut well on steeper slopes or uneven surfaces
• Fuel or electric cord and nearby power point required
• Expensive to buy

Rotary mowers

Rotary mowers have a single blade which spins around horizontally under the mower. They have four wheels and you can raise or lower the deck to change the cutting height.

Pros:

• Cheaper to repair and replace parts than cylinder mowers
• Mulch or grass collection options
• Better at cutting rough or tall grass than cylinder mowers
• Cheaper to buy than cylinder mowers

Cons:

• Electric cord and nearby power point or fuel required
• Does not cut wet grass well
• Does not cut right to the edge of the deck which can leave uncut sections along fences or walls
• Does not produce stripes
• Does not cut as short as a cylinder mower

Hover mowers

Hover mowers force air down which lifts the deck so that they hover over the surface of the ground so that they don’t require wheels.

Pros:

• Adapt well to uneven ground surfaces
• Can move in any direction for difficult shaped lawns
• Easiest to use on steep slopes
• Cheaper to buy than other mower types

Cons:

• Electric cord and nearby power point or fuel required
• Does not cut wet grass well
• Does not cut right to the edge of the deck which can leave uncut sections along fences or walls
• Does not cut as evenly as other types of mower as some of the grass is blown flat by the downdraft

Automatic or robot mowers

Robot mowers automatically mow the grass very regularly, in fact daily when it isn’t raining. This means that they cut off only a very little at a time and the short clippings mulch the lawn. A perimeter is set up by pinning a wire down to the ground and the mower cuts the whole area evenly and returns itself to its base unit for charging or when it is raining. They are expensive to buy but in the long run can be cheaper than paying for someone to mow the lawn.

Fertilising 

Like any other plant, grass plants need enough nutrition to grow. A hungry lawn will look yellow as it becomes deficient in nitrogen.

Scarifying

Scarification removes moss and dead grass from the lawn. It can be carried out by hand with a spring-tine rake or with a scarifier machine.

Top-dressing

Top-dressing is the process of spreading sand, fertiliser or soil onto the surface of a lawn and is carried out annually. The top-dressing material applied should be tailored to the needs of the lawn.

Aerating

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Aerating is a process which reduces compaction in a lawn and adds air pockets to the soil which improves grass growth.

This can be carried out on a small area using a hand fork as in the picture above but the best method for larger areas is to use a hollow tine aerator which can be manual or engine powered.

Reseeding and repair

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Sometimes areas of a lawn can be damaged by:

• Moles
• Drought
• Flood
• Animals digging
• Machinery
• Wear from walking e.g. along a particular route to the washing line
• Overgrown plants