Slitting has historically be the most common treatment carried out on sports turf in this country as it introduces air into the soil profile whilst causing minimal surface disturbance.
Working depth usually varies from 75mm to 150mm on pedestrian units, down as far as 300mm on the larger winter pitch aerators. Many tractor mounted units have pressure frames or are controlled by downward pressure from the tractor to give variable depth of penetration and to facilitate full depth when needed.
The myth that you should always slit as deeply as possible is inaccurate. Always aerating at the same depth is likely to create a soil pan at that depth, obviously less of a problem at 300mm than 75mm but a problem nonetheless. Frequency of slitting must relate to the quality of soil to be worked and the needs of each specific site. Anything from weekly to monthly could be appropriate.
Generally it is best to work in the same direction during any one slitting season or on slight diagonals as cutting across previous slit marks could promote serious disturbance to the playing surface, if not immediately then certainly through dry summers. Slitting can be overdone and result in unevenness; a situation exacerbated during frosty spells, or on heavy saturated soils when taking any machinery over the ground will cause more harm than good.
Starting a slitting programme for the first time can be disruptive though after a few passes lifting should be kept to a minimum. The initial damage is usually due to poor rooting, a direct consequence of no, or limited, aeration work in the past. Units drawn behind compact tractors are usually equipped with a grooming roller on the back to smooth any lifting.
