Scarifying the Lawn

Lawn scarification or dethatching as it is also known, is the process of removing thatch or organic matter by mechanical means using a powered machine called a lawn scarifier or lawn de-thatcher.

Over a period of time, lawn thatch or organic matter will slowly accumulate in the base of lawn, this is especially true on neglected lawns that receive little or no maintenance. When this accumulation of organic matter becomes excessive it needs removing, or the health of the lawn will suffer and start to deteriorate.

A lawn scarifier or dethatcher is a powered machine that consists of vertically mounted knife like tines or wire rake type tines. These tines spin and penetrate into the grass sward and remove unwanted debris or thatch.

Alternatively a hand held spring tine rake can be used but will not remove the amount of debris as a powered scarifier. Hand scarification is also very hard work and only really suitable for small lawns unless you want a good workout.

Deep scarification can leave a lawn looking thin, therefore it is important that it is undertaken during periods of good consistent growth. Avoid this operation during periods of drought or cold weather where recovery will be slow.

Why scarify a lawn

There are numerous reasons why a lawn might be scarified

• As we have previously touched upon lawns are primarily scarified to prevent or remove the build up of thatch. The disadvantages of thatch can be found in more detail on the lawn thatch page.
• Scarifying is also carried out in the spring time (as part of the spring lawn care program) to remove moss from the lawn after treatment. Moss is most prevalent during the springtime and may people apply a moss killer to kill it off. After the moss has died it should be removed in the form of raking or scarification before moving on to the next task.
  
  
• The most intense scarifying operation is carried out during the late summer as part of the autumn renovation program. This scarifying operation creates a nice seed bed prior to overseeding and is very important in the successful establishment of the seed. This is because intense scarifying helps bring the seed into contact with the root zone or soil beneath the surface of the lawn.
  
  
• Light regular scarifying operations during periods of strong growth in the summer can prevent thatch build up and remove any unwanted lateral growth. This gives the lawn a very tidy, cared for look just when you want the lawn to look it's best during the summer months.
  

Scarifying helps keep the lawn in a healthy condition by keeping the thatch layer in check. A lawn that has excess thatch will have poor drought tolerance, poor drainage and weak grasses that suffer from wear.

When to scarify a lawn

Lawns can in fact be scarified any time during the growing season providing suitable conditions apply. However the most common times are spring and late summer or early autumn.

Scarifying in the spring time is often carried out after any moss control or treatment. Scarifying removes the moss from the lawn once it has been killed. It is important not to scarify to early in the spring when there is little growth, wait until there is sufficient growth to aid a speedy recovery.

The ideal time and most intense lawn scarification is undertaken late in the growing season (late August - early September) as part of the autumn lawn care program. Again it is important to complete the program whilst there is still sufficient growth for the lawn to make a full recovery.

Light scarifying (often called verti-cutting or grooming) can be undertaken during periods of strong growth during the summer. This helps to prevent any thatch build up and prevents any lateral growth and keeps the lawn looking tidy and cared for.