Scarification can be a daunting process but following our tips on scarifying a lawn will guarantee a healthy and neat garden. Over time dead leaves from mowing can build up between grass, along with moss and weeds. If you part the grass on your lawn, you will observe a brown layer of dead looking material above the soil, called thatch. This must be removed periodically to allow the grass to grow properly and scarification will clear this away without damaging the grass itself. Water, air, and sunlight will then reach the grass properly to give a healthy, thick, and evenly coloured lawn.
Lawn scarifiers, also known as dethatchers, look much like a bulky lawnmower and perform a similar function. In addition to cutting grass to promote new growth, the knife like blades on the cylinder beneath cut into the soil as they rotate. These cuts allow air to penetrate and aerate the underlying soil, providing oxygen to the grass roots. They also rake through the thatch at the base of the grass, removing dead grass, fallen leaves and moss. The refuse is collected in an attached bag for easy disposal. On smaller lawns, the thatch can be removed with a sturdy metal lawn rake, but this is time consuming and physically demanding work. For larger areas, an electric or petrol powered scarifier does the same work in a fraction of the time with little effort. As grass grows, it puts out stems called stolons that run along the ground, growing a clone of the original plant at the end. Left unchecked, these can give your lawn a dense, knotted appearance and a spongy texture underfoot. Scarifiers either cut through these or draw them upwards ready for cutting and regrowth. This aligns the grass stems in an upright position, giving a regular consistent texture across the lawn.
Removing the dead organic matter, moss and weeds in the thatch allows the surface of the ground to breathe. The cutting action furthers this, allowing oxygen to penetrate the soil and the removal of other plants prevents them absorbing oxygen before it reaches the soil. A thick layer of thatch can also stop water from reaching the soil, creating a soggy mulch between the grass plants. This will deny the grass the water it needs for healthy growth and can encourage fungi that thrive in dark, damp conditions. Finally, if the thatch is too thick it will also prevent sunlight from reaching new grass shoots. Grass needs energy from sunlight to effectively photosynthesise and grow strong new shoots. If your lawn is denied any of these vital elements it can lead to a yellow, patchy appearance and scarification is needed to remedy this. While a layer of thatch from 0.5 – 1cm is beneficial to the lawn, providing nutrients and insulation, a scarifier will remove any excess.
While intensive scarifying is usually done in late Autumn (typically August to September), lighter work can be done in the Spring. It should never be done during Summer as hot, dry weather can cause the soil to dry out and deny the lawn vital moisture. Winter scarifying can allow excess water to penetrate the soil and freeze, causing the lawn to heave up and killing the grass. In the Spring, scarification should be carried out from late March to April to allow the grass to become established. This also allows maximum time for regrowth during the sunny summer months. Moss killer should be applied 7 – 10 days before to avoid spreading moss spores during scarification to grow elsewhere. Cut the grass a week before, removing the excess grass and cutting through thick areas of thatch prior to scarification. The soil should be moist but not wet, ideally after light rainfall, if the soil is wet the scarifier can tear the grass out by its roots.
After moss has been killed off and the lawn mowed (but no shorter than 2cm), it is time to bring on the scarifier. Adjust the blades or wires on the cylinder to remove the top 1cm of thatch. Start at the perimeter of the lawn and make two complete circuits. This gives room to turn when scarifying the main body of the lawn at the end of each pass. Next, scarify the lawn in straight lines up and down, then make a second pass working diagonal to these lines. Do not make the second pass at right angles to the first as this could cause excessive damage to the lawn. For a Spring scarification this should be enough to clear the debris as little thatch should have built up since Autumn. If this is the first time the lawn has been scarified or an Autumn scarification, heavy thatch build up may necessitate further passes. The blades can be lowered for further passes until all thatch is removed. This may leave a sparse, bare looking lawn but is necessary to rejuvenate the lawn and return it to perfect condition.
Do not panic if your scarified lawn looks terrible at first, this is perfectly normal. If anything, it demonstrates how much dead and undesirable material was taking the place of healthy grass. Remove any thatch that has been cut away, if the scarifier has an attached bag it should be emptied regularly during the process. Mow the lawn again in different directions to the scarification to ensure a consistent level to the remaining grass. The cleared, aerated sections are now ready for overseeding. Fertilise the soil, sow new grass seed where needed and top dress with sand and loam to aid recovery. If the weather is particularly hot or dry after sowing, ensure the lawn is watered regularly. Within 6 weeks the new seeds will have germinated, filling any blank areas and the lawn can be mowed to a consistent, regular level.
SERV Plant Hire are plant and machinery specialists offering a huge variety of construction and landscaping equipment for hire to the North West of England. Contact us to discuss your lawn scarifier hire requirements, we will be happy to help.