WHAT, WHY, HOW

Lawn Aeration

Hollow tine fork

WHAT, WHY, HOW

Lawn Aeration

What is lawn aeration?

Aeration is the process of creating space in the soil, channels for air (oxygen) to circulate and improve the soil and its microbes and good bacteria (and many other benefits – see below). However, if it was simply a case of sticking holes into the ground, we’d all have perfect lawns. Done correctly and at the right time aeration is the key to a healthy lawn, but understanding ‘why’ is essential to understanding ‘how’.

aerated lawn IN AERATION 2

What are the benefits of lawn aeration?

Aeration is the the single most effective thing you can do to improve your lawn.

Lawn aeration is all about the lawn soils. It’s also about the bacteria and microbes that are essential for quality soil. These, and the grass plants themselves, need a healthy soil environment, roughly 50% solids, 25% water and 25% air. Over time, however, the weight of human, animal and machine traffic can lead to compacted lawn soil that is starved of oxygen. Extreme wet weather can also impact, with excess water squashing out the air. Aeration redresses this to regenerate a healthy soil and growing environment.

Are there other ways that aeration improves my lawn?

Yes, definitely! Here are the key additional benefits of aeration:

  • Gaseous exchange – the adding of oxygen to our soils also aids the release of CO2
  • Improved soil drainage, depending on type of aeration carried out
  • Improved surface drainage
  • Improved thatch control
  • Improved moss control
  • Improved fertiliser uptake and longevity
  • Improved water holding capacity in soils
  • Improved erosion control
  • Reduced need for irrigation, herbicides, fungicides, etc
lawn aeration
Hollow-tine aeration
Close up of a soil core after lawn aeration | Lawn Association
Close up of a 'thatchy' soil core after hollow tine aeration of a lawn

Hollow tine aeration – solid tine aeration – slitting – which should I use?

Hollow tine, solid tine and slitting are the three main types of aerating methods (each with specific tools/machines), and your choice depends on the condition of your lawn (e.g. the degree of compaction, drainage problems, thatch etc). The one tool that you do NOT use (except for very small areas) is a garden fork – this is a crude and inefficient way to get air into your soil and it will NOT solve your compaction problem!

Hollow tine

Using hollow cylindrical prongs, this removes numerous narrow sausage-like plugs from your lawn soils. And so, you create those essential air channels but without squashing the soil. Done by hand or machine, it will deliver the most benefit for the least amount of effort.

Solid tine

By pushing solid prongs into the soil, this is a more controlled version of the garden fork. It can give good results for increasing oxygen, but is not ideal for a domestic lawn as it squashes the soil around the holes, adding to any existing compaction problem (and certainly not a good option on clay).

Slitting

This puts a ‘slit’ into the soil to keep the surface open. It also slices through shoots and stolons (pruning to encourage better sideways growth) and improves root development. It is generally done during winter as, with larger holes (slits), the soil can become too dry in warmer months.

When should I aerate the lawn?

All forms of lawn aeration will dry out the top surface and so should only be done when the soil has good moisture. This means, typically, you can aerate from September through to April/May (or March for slitting) but be guided by the prevailing weather conditions.

How often should I aerate?

There are no rules about frequency – you can aerate just once a year or up to 4 times if necessary. You can even aerate monthly during the correct months if you use a pencil-tine with its smaller diameter which causes less surface disruption – but follow up with a top dressing each time.  

HOLLOW TINE AERATION: Given the spacing between the tines, the machine or tool will typically aerate approximately only 5% of the overall lawn area, leaving plenty of soil untouched. So, while once a year is the minimum, twice is better.   

SOLID TINE AERATION: This should only be done if you have very good soils, although on any soil it will improve surface drainage to some extent. If this operation is for you, then you can do this as often as conditions will allow.

SLITTING:  If using slitting, this should be done frequently to be effective; weekly or fortnightly during winter is generally sufficient.

What do I do after aerating my lawn?

First of all, be patient – the benefits of aeration take time to materialise. Secondly, aerating does create some mess – small soil clumps, and holes all over the grass. You can either remove the plugs of soil or, since they contain lovely bacteria that the soil needs, leave them to break down naturally (but put up with mess for a little longer) or use a scarifier set at ground level to turn them into a beneficial top dressing.

Breaking up soil cores after lawn aeration | Lawn Aeration
Scarifying after hollow tine aeration, to convert soil plugs into top dressing

Want to know more?

Become a member and get advance notice of our e-learning and our training courses.