Aerating Lawn With A Basic Bow Rake?

(Question)

If I want to aerate a small lawn in west end toronto, can I bob my bow rake up and down across my lawn and my neighbours’ lawn? It just cuts down on my clutter, and I just want to vent. I realize it doesn’t pluck out soil like the specialized garden tool. I did a great job aerating the soil getting rid of dandelions, and get better every year. Thank you.

(Answer)

Thank you for contacting Toronto Master Gardeners with your question about lawn care. Aeration is a necessary component of optimal lawn maintenance. The mechanical removal of small plugs of thatch and soil from the lawn facilitates air exchange between the soil and its surrounding atmosphere. The benefits of aeration are many: it enhances soil water uptake, improves fertilizer uptake and use, improves turfgrass rooting, allows oxygen into the soil, and reduces weed growth. Lawn aeration also breaks up compacted soil, allowing water, air, and nutrients to permeate into the root zone.

Aeration also speeds up thatch breakdown. Thatch is the loose, organic layer of dead and living material in the lawn. It consists of shoots, stems, and roots that develop between the zone of green vegetation and the soil surface. When thatch builds up to more than one inch of height, it can hold excessive water, leading to reduced oxygen that reaches turf roots. It can also increase pest problems by harboring disease-causing organisms and insects. Lawn aeration in the spring or fall controls lawn thatch.

There are different methods of aeration. One, sometimes called spiking, may be achieved with the bow rake method that you propose, but this approach is best for superficial lawn problems. It is not the same as core aeration. Coring breaks through the thatch layer opening up those opportunities for air and water movement. Aerating machines remove plugs of soil from the turf area creating a system of pores by which moisture and plant nutrients are taken into the soil. They allow carbon dioxide to escape from the soil and oxygen to enter. A rapid intake in movement of water and air is necessary to correct damages to a lawn caused by compacted soils.

Equipment having solid tines or spikes such as your bow rake will not achieve the objectives of true aeration. Aerators always remove a soil core whereas solid tine spikers do not. A 2016 article by Penn State Extension warns that spikers actually increase soil compaction as the movement of the soil to sides of the hole produced by the solid tine forces the soil into a denser mass. However, since you were happy with the past results of this method, and since your goal does not seem to be that of a lawn professional, you may have little to lose by trying. Since you are not doing core aeration, in the fall, make sure you remove as much lawn thatch as possible by raking deeply and not just skimming the leaves off the top of the lawn.

Spring and early fall are the best times to aerate. Summer aeration of cool-season grasses like Kentucky bluegrass, perennial ryegrass and fescue, is not generally recommended because these grasses are in a semi-dormant condition. During the summer, crabgrass is quite active. A safe general rule for time of aeration is to aerate only when the desirable grasses are growing vigorously.