All soil types are vulnerable to compaction, although heavy clay soils are more prone to this than light sandy soils due to the small soil particles of clay. Lawn aeration is relieving compaction and increases air space to help promote healthy growing conditions for grass.
Compaction is basically a result of compression placed on the soil particles, which causes a breakdown in soil structure resulting in a lack of air. This, in turn, harms the health of the lawn, often resulting in weak grass coverage.
Compaction causes the pore spaces in the soil to become small, thus reducing the amount of air held in the root zone. This inhibits drainage, hurts rooting, and encourages shallow-rooted grasses, reducing drought resistance. Over a period of time, lawns can become compact, especially if they are heavily used and receive little or no aeration.
Lack of air also hurts microorganisms in the soil, which need air to survive. Microorganisms are required to break down the thatch layer and return nutrients to the plant. Overall a lack of air has a detrimental effect on the health of your lawn.
The benefits of aerating the lawn
The purpose of aerating is quite simple, to let air and water into the soil and relieve compaction.
A healthy well-aerated lawn has several benefits; these benefits include:
- An increase in desirable bent and fescue grasses over annual meadow grass. Bents and fescues being easier to maintain, are more drought-resistant, require less fertilizer, are more disease resistant (especially against fusarium patch). They produce a better quality lawn (Bents and fescues are the favored grasses on golf and bowling greens).
- An improvement in rooting, producing a healthy drought-resistant lawn.
- Encourages microorganisms that are beneficial to the soil as they aid thatch breakdown. They are also beneficial in helping with disease resistance as they inhibit the pathogens that cause the disease.
- Aids irrigation by helping the water go down to the roots and reduces surface runoff.
- If lawn aeration is carried out before top dressing, it helps improve the soil structure as the top dressing fills the channels created by the aeration.
- It can also be beneficial to drainage by creating channels for the water to penetrate and drain away.
When to aerate your lawn
Generally speaking, it is best to avoid aerating during droughty periods during the summer. However, shallow spiking using solid tines may benefit irrigation by helping the water to go into the soil, where it is most needed. Avoid any deep slit tining during the summer, as this can cause the ground to open up if it turns scorched. Aeration can be carried out at any time during the year subject to ground and soil conditions. Ideally, the soil needs to be slightly moist to get the full benefit from aeration. Avoid aerating during frosty conditions; the obvious reason is that you will damage the grass. Also, avoid aerating during periods of very wet conditions if using a heavy machine (using a garden fork may be acceptable for localized areas prone to flooding.
The ideal time for aeration is during the spring and autumn as part of the respective lawn care programs. Aerating during these periods means the aeration can be incorporated with other operations which complement each other such as overseeding and top dressing.
The different types of lawn aeration
There are a few different types of lawn aeration, with many different implements and machines on the market. We will explain the different types of aeration and the different benefits that each has. They are as follows:
- Spiking or Solid Tining: Probably the most common type of aeration on a lawn because most people have a garden fork. However, there are machines available for this task. Spiking is particularly useful during the summer months before irrigation to help the water penetrate the soil profile. Spiking is preferred to slitting in the summer since the slits are prone to opening up if it is dry.
- Slitting: Slitting is not as common as spiking for lawn aeration. However, there are benefits of slitting over spiking. They can generally penetrate deeper than spikes and also have the added benefit of root development as slitting prunes the roots. Deep slitting would be used in the autumn and winter months.
- Hollow Tining or Core Aeration: This process involves the removal of cores from the lawn. The main benefit of this method would be to remove thatch. This is also very beneficial before top dressing as it leaves larger holes (which stay open than other types of aeration. Therefore it is easier to work in top dressing through the holes and into the root zone.
Core aeration, hollow tining the lawn
Core aeration (hollow tining) is a lawn aeration technique that physically removes small cores or plugs from the lawn to create a healthier environment for grass growth.
Core aeration is also called hollow tine aeration. Small hollow metal tubes are punched into the lawn surface, with the cores being ejected from the soil onto the surface of the lawn.
Types of core aeration machinery
Core aeration or hollow tining can be undertaken with either a powered lawn/core aerator, a tow-behind aerator, or a simple hollow tine hand fork.
- Powered core aerator – These machines are generally powered by a petrol engine and are designed to cover large lawns in a short space of time. The tines can either be mounted to a cylindrical frame, drum, or spool, penetrating the turf as the drum rotates over the lawn. Alternatively, the tines may be mounted on legs that are attached to a cam-type system. On this type of core aerator, the tines are punched vertically into the lawn to remove the core or plugs. Punch action core aerators generally penetrate deeper into the soil than drum-type aerators.
The main disadvantage of these machines is the cost of purchase. In most cases, it is better to hire rather than purchase a powered core aerator or use an alternative method to aerate the lawn.
- Tow-behind core aerator – As the name suggests, these core aerators or towed behind a garden tractor or similar. The tines are fixed to a drum or spool, which penetrates the lawn, removing the cores as it travels over the lawn. Some models have a weight tray to add extra weight to the machine to increase tine penetration. Tow-behind aerators are great for large areas, and the cost of purchase is quite reasonable, making them an ideal alternative to powered core aerators. The main drawbacks are the tine’s lack of penetration depth and unsuitable for small, tight lawns.
- Hand core aerator fork – These simple tools are top-rated for core aeration and are designed similar to a hand fork, but hollow tines replace the standard fork tines. They are pushed into the soil to remove the cores. These implements are ideal for smaller lawns where larger machinery is difficult to maneuver. They are not really suitable for large lawns as they are very time-consuming and can be very laborious. If the soil conditions are moist, full tine depth can be reached, ensuring an extensive job.
Why core aeration
There are numerous benefits that core aeration has over standard lawn aeration, such as spiking and slitting. As we have already stated, core aeration (hollow tining) removes cores, while other types of aeration punch holes in the lawn. The major benefits of removing cores are:
- Reduce the influence of thatch on the lawn – An excessive layer of thatch in the lawn is one of the primary reasons for poor lawn health and countless other common lawn care problems. Hollow tining or core aeration physically removes the thatch from the lawn, resulting in a healthier lawn with fewer problems.
- Incorporate a soil exchange program – Many lawns suffer from various problems such as lack of drought resistance or poor drainage. It is possible that these problems can be alleviated with core aeration. As core aeration leaves wide, deep holes in the lawn, a suitable top dressing can be applied and worked down the core holes and into the soil. If done regularly, the soil composition can be gradually changed to help rectify the underlying problems with the soil.
- Relieve soil compaction – Although all types of aeration help relieve soil compaction, core aeration is more beneficial than other types of lawn aeration. This is because where the cores plugs have been removed, the surrounding soil is allowed to expand, thus being more effective at reducing soil compaction.
When & how to core aerate a lawn.
Although core aeration can be carried out almost any time during the year (ground conditions permitting), the growing season is the best time; late summer or early autumn is preferable. This is because it complements the autumn lawn care program, which also includes overseeding and top dressing. Both of these two tasks will benefit greatly from core aeration being carried out before them.
However, if you have a serious problem with excessive thatch build-up, or need to change the composition of the soil by applying the top dressing, then core aeration can also be undertaken during the spring or even at suitable times during the summer again weather and ground conditions permitting.
This task is best carried out when the lawn surface is dry. Before aerating, mow the lawn, as this will help with core collection.