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Lawns: mowing

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last updated Aug 3, 2009
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Mowing a lawn. Credit: RHS.

All lawns need mowing; it is one of the most frequent, and most important, tasks in maintaining a healthly lawn. Getting the cutting height and mowing frequency right can make a huge difference to the ongoing health of the lawn.

Types of lawn mower Back to top

There are many different lawn mowers available to purchase. Your lawn mower will probably be one of your most-used pieces of power gardening equipment, so take some time to consider what type of mower you need before purchasing one. Think about the following:

Electric or petrol: Electric mowers are cheaper to buy than petrol mowers, but are really only suitable for smaller lawns, as you'll be trailing a power cable behind you as you mow. They are also not as powerful as petrol mowers.

Lawn size: Mowing a big lawn could take more than hour each time. Choosing models with a wider cut can make a significant difference to the time taken for a modest increase in purchase price. If you have a really large lawn, consider a self-propelled model or a ride-on mower.

Lawn type: Not all mowers are created equal! Some will give a much higher quality cut than others. If you are after a high quality finish, consider a cylinder mower. This type of mower cuts a lot shorter, and is good for achieving a striped effect.

Maintenance: You'll get the best results with sharp mower blades. You can sharpen rotary blades yourself, but for sharpening a cylinder mower, you're best to take it to a professional.

Mower types

There are four main types of mower: cylinder, rotary, hover and ride-on. Mulching mowers are another mower you will come across, but these are a type of rotary mower.

  • A cylinder mower gives the highest quality cut, suitable for fine lawns and sports turf. The blades are arranged on a cylinder and cut with a scissor-like action. This produces a very fine cut, a striped finish and allows very low cutting heights.
  • A rotary mower is suitable for most ornamental lawns. This mower has a horizontally spinning blade. A rotary mower will not give as fine cut as a cylinder mower, but it will cut longer grass and handle uneven surfaces much better than a cylinder mower. Ones with a rear roller are available that will give a striped finish.
  • A hover mower is a rotary mower, but sits on a cushion of air instead of wheels. It too is able to handle long grass and uneven surfaces. Self-propelled versions are not offered.
  • A mulching mower is a type of rotary mower. Most lawn mowers come with a collection box to collect the clippings, but mulching mowers instead chop up the clippings very finely and deposit them back into the turf. The clippings settle at the bottom of the sward and are barely visible. Using a mulching mower will return nutrients lost in the clippings back to the root zone. However, when mulching mowers are used for very lush growth (when the grass is long), the excess clippings may have to be collected and placed on the compost heap.  Some models have to option of mulching or collection and are to be preferred.
  • A ride-on mower is usually reserved for very large lawns. These may be cylinder or rotary. It will cut down on your mowing time, but these mowers are much more expensive than any of the ones listed above.  Pedestrian self-propelled models are a cheaper alternative for large lawns.

When to mow Back to top

Mowing is carried out mainly between March and October.

  • Over summer: On average, mow twice weekly, dropping to once a week during periods of drought.
  • Over spring and autumn: Mow once a week.
  • Over winter: Mowing is usually not necessary, unless the weather is mild and the grass is still growing. In this case, mow occasionally with a high cut setting. Do not attempt to do this if the ground conditions are very soft or frozen, or during spells of cold, drying winds.
  • 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.

How to mow Back to top

Mowing itself is relatively straight forward. It is the mowing height that can cause problems. Follow these tips to get the correct height:

  • 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 although attractive, it can weaken the grass, encouraging shallow rooting and making the lawn more susceptible to drought, weeds and moss. Close mown lawns need more frequent feeding and watering. Extremely low cutting may scalp the lawn, leaving bare patches where there are bumps or tree roots protruding above the surface.
  • On the other hand, lawns regularly cut too high can suffer from loose, weak growth that is less durable as a 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.

Getting a striped finish

A striped lawn looks very impressive, and isn't that difficult to achieve if your mower has a rear roller.  Wheeled rotary mowers do not produce good quality striping.  Rectangular lawns are easier to stripe than irregularly shaped lawns, but with a bit of practice, you can stripe up any lawn.

  • Start by mowing around the edge of the lawn.
  • For square or rectangular lawns, work from the left side, mowing up and down the lawn using the straight lawn edge as a guide to get a straight line.
  • For circular or irregular shaped lawns, line up the mower with a focal point to achieve an initial straight line across the widest point. This first straight line can be your guide for subsequent stripes.
  • At each turn, line up the mower so that the next mown stripe slightly overlaps the last.
  • Empty the clippings box regularly. A full box can deposit clumps of clippings on the lawn, spoiling the finish and clogging the mower.
  • Tight corners may need strimming or hand trimming with lawn shears, if they are too small or boxed in for the mower to reach.

It is a good idea to vary the direction of cut, alternating straight with diagonal stripes on different occasions, so that ruts do not form in lawn from going backwards and forwards in the same direction on numerous occasions.

Problems Back to top

Scalping of the lawn may occur:

  • On soft ground (when the wheels sink in).
  • On turns (if they are taken too fast).
  • If ruts in the lawn form from not varying the direction of cut.
  • If the height of cut is too low.
  • If the lawn surface is uneven, with bumps and hollows. These are best levelled out. See our advice on repairing lawns for further information.

An uneven finish, with torn grass is usually caused by blunt blades. However it can also occur if the bottom and cylinder blades of a cylinder mower are incorrectly set. Consult your owner’s manual for details of setting the blades correctly. Ragged cuts can also occur when the grass has been left to get very long, when the mower is operated too fast, or when the cutting height is set to maximum.

Quick facts

Suitable for All lawns
Timing Mainly between March and October
Difficulty Easy to moderate
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