Benefits to aerating
Relieves soil compaction allowing water and nutrients to get to the root zone to enable the lawn to benefit from them. Encourages roots to develop, enabling your lawn to survive dry spells better. Better oxygen flow to soil encouraging vital microbial activity.
How to aerate
There are 2 main types of aerating, hollow tine aearting where holes are punched in the lawn and a core is extracted and solid tine / blade aeration where the lawn has slits cut or a solid spike punched into it.
Hollow tine aeration is most beneficial when performed at the correct time of year, Spring and Autumn. Solid tine aeration can be used in Summer where you don't want the lawn to dry out more from the holes created in dry spells.
Once you have chosen which type of aeration to do, you can select the best product. If you want to hollow tine the choice is hiring a machine for around £150 a day which will cover a large area quickly, or to buy a manual aerator. For small lawns under 75m2 a manual aerator would be the recommendation. These are like garden forks, just ensure you purchase a good one that does not clog (Lawn-Kit aerator is a great choice) otherwise you'll spend more time unclogging the tines than using them. For larger lawns the choice is to to hire a machine or to buy a manual aerator. A machine is less effort but if you wanted to do the job twice a year it can cost £300. If you don't mind putting some effort in you can use a manual aerator and aerator the lawn over a few sessions and once you have the tool can do this as often as the lawn needs at no additional expense.
If you are using solid tines or blades, some scarifies have blades designed to cut into the lawn surface to help airflow. They have limited impact but are better than nothing in the summer and can cover a large lawn relatively quickly. For spikes you can use a garden fork, a proper aerator with straight spikes is slightly easier and faster (we have solid tines available to fit the Lawn-Kit aerator). For a large area there are rollers with spikes available. There are cartridges for some cylinder mowers that do this, you can also get manual sarel rollers to push over the lawn. These need to be reasonably heavy to ensure the spikes penetrate the surface to any depth when the ground is hard. We would avoid the spiked shoe option at all costs.