Regularly scarification is extremely beneficial to its overall health and vigour. Scarifying lawns is often referred to raking, verti-cutting and de-thatching too. All of them are pretty much the same thing.
The are a couple of key reasons why we want scarify the lawn. This first is to remove dead moss from the turf, following an application of moss killer, such as lawn sand. Scarifying moss is usually undertaken in the spring time, as this is when moss is most troublesome in turf.
The second reason is to prevent and remove thatch from the lawn. Thatch is an accumulation of organic matter that forms beneath the grass. It consists of dead or decaying shoots, stems and roots. While a little thatch is beneficial, too much has an adverse effect on the health and vigor of the turf.
Scarification helps prevent the build up of thatch by removing it. Late summer is the preferred time of the year for thatch removal, as there is plenty or warmth left in the ground. This enables the lawn to make a speedy recovery from what can be an intensive operation.
Although moss and thatch removal are the main reasons for scarifying lawns, there are other benefits of scarifying:
- Create a seedbed prior to over-seeding: Many keen lawn enthusiasts over-seed their lawns to improve the turf quality. Scarifying beforehand creates an ideal seed bed, which helps the grass seed sit just below the surface of the lawn. This gives the seed an excellent chance of germinating and establishing.
- Discourage weeds and weed grasses: Certain lawn weeds like yorkshire fog, trefoils and speedwells do not like being disturbed. Therefore a light raking prior to the lawn being mown can help weaken and discourage these weeds.
- Encourage fine grasses: Frequent light raking (sometimes called grooming) during periods of strong growth can help remove any lateral growth and reduce coarse grasses. This will encourage desirable finer grasses like fescue and bents.
When to scarify the lawn
It should be noted that intensive scarifying can leave the lawn looking very ragged and thin. Therefore it’s important it is undertaken when the grass is going to recovery quickly. This of course means during the growing season. Never scarify during the winter, when growth is very slow or has stopped altogether.
Lets take a look at the key times of the year to scarify the lawn:
- Spring: The initial scarification should be in the spring time. This usually follows moss treatment and control, to remove the dead moss. However, even if no moss is present a light scarification will still be beneficial once the soil temperatures have risen and growth has picked up. Avoid scarifying until the grass is growing consistently, don’t be tempted to go too early.
- Summer: Although many gardeners talk about scarifying in just spring and autumn, there are benefits to frequent light treatments during the summer months. Again it should be only done during periods of growth to aid recovery. Avoid doing anything during periods of drought, as this can weaken the lawn. During the summer, the scarifier should not penetrate into the soil, it should only flick through the grass. This helps remove any lateral growth and gives the lawn a clean, tidy appearance. When carried out during the summer is is sometimes called grooming or verti-cutting, it should not as aggressive as scarification during the spring and autumn.
- Autumn: This is the time for deep scarification, if the ground and growing conditions allow. September is often a good time for deep scarification, as the soil is likely to be moist and there is still enough warmth for the lawn to make a full recovery. Scarifying in the autumn can be included in the autumn renovation program. Other tasks in the autumn program can include aeration, over-seeding, top dressing and feeding.
Preparing for lawn scarifying
If you intend to scarify you require suitable weather and ground conditions to help make the operation go as smooth as possible. Remember we need sufficient growth to help the lawn make a speedy recovery, this is more applicable to the spring, which can still be relatively cool with overnight frosts. Wait for growth before scarifying.
We also need adequate moisture in the soil for the best results. If the soil is too dry then damage to both the lawn and the scarifying machine may occur. At the same token a lawn that is too wet or waterlogged will make for a messy job, also the scarifier won’t remove the debris effectively.
A day or two prior to scarifying, mow the lawn a little shorter than normal, without stressing or scalping the lawn. If the grass is shorter the scarifier will produce a cleaner, more efficient job and there will be less debris to collect. Long grass tends to clog the scarifier and reduce effectiveness.
Scarify the lawn when the grass is dry, again this produces a tidier finish making the clean up process a lot easier.
Hollow tine aeration, which is sometimes referred to as coring is the process of removing soil/thatch from the lawn. Hollow tines are small circular tubes that are pressed or punched into the turf, each time they penetrate, a small core or plug of thatch/soil is removed. This form of aeration has many benefits:
- the breakdown of thatch / organic matter – As hollow tining physically removes thatch from the lawn, it is an excellent way of removing vast quantities, keeping the thatch in check and at a manageable level. It also has a beneficial effect on the soil organisms, by increasing air space and movement in the soil, vital for a healthy population of organisms. Soil organisms/bacteria help break down the organic matter in the soil, thus keeping the thatch layer in check.
- Relieves soil compaction – This type of aeration typically creates more airspace than other methods, such as spiking and slitting and will have a greater impact on relieving compaction.
- Improves surface drainage – Coring helps keep the lawn drier and firmer by removing surface water. This helps by preventing many lawn care problems including moss, turf disease and certain weeds.
- Integrate top dressing into the soil profile – Hollow tining is great way of getting a suitable soil/sand mixture (top-dressing) into the soil profile prior to top-dressing. It will also help seed germination and establishment if it is carried out after over-seeding.
- Increase soil temperatures – Removing water and increasing air space in the upper soil profile will increase the soil temperature, promoting better grass growth, particularly during the spring time.
- Increases pore space – Allows oxygen to enter and carbon dioxide to escape the soil, resulting in healthier growing conditions.