One of the most common questions we get in the horticulture department of Nebraska Extension is “hey, should I aerate or power rake my lawn?”. We hate to answer the question with “it depends”, but that’s really the answer, because each procedure is done for a different reason.
Reason for doing it – The main reason for aerating a lawn is to improve drainage of water. If you see water puddling on the lawn for several hours after a rainfall or irrigation event, that means that the water is not moving downward into the soil profile as it should, usually due to compaction. Aerating the lawn will help to reduce compaction and increase infiltration.
Other Benefits of – In addition to increased water movement, an increase in oxygen penetration is also realized, which increases the overall health of the turf plants. Aeration is a type of root pruning, which increases the number and depth of the roots of the lawn roots, which is a great benefit, especially in the heat of summer. A third side benefit is the opening of the turf, which facilitates the downward movement of any product that is applied to it including fertilizer, insecticides, fungicides and seed.
How to do it – An aeration machine is a bit pricey, so renting one from a hardware store or rental store is the common way to go. You’ll need a pickup truck/SUV and a friend to help you unload it and load it up again for return. Before leaving the store, check to see if the tines are new or have been replaced recently. A core aerator will do a much better job if the tines are sharp. On the day before aerating, start by applying about a half inch of water to the lawn and let it soak in. Then, bring the machine home, start it up and run it over the lawn in a north-south direction, then in an east-west direction.
When to do it – Since the process is slightly injurious, it’s best to aerate at a time when the lawn is able to recover, or you can reseed it. For cool season lawns, this is late April and May or September/October; for warm season lawns, June is a good time.
Reason for doing it – The main reason for power raking is to remove excess thatch, which is the brown “shredded wheat” like tissue that lies on top of the soil. If the layer is more than 3/4ths of an inch, it’s time to power rake.
Other Benefits – A great side benefit of power raking is the preparation for over-seeding that it provides. Other than loosened bare soil from a pitchfork, there’s nothing better than a power rake. Aeration provides a little seedbed preparation; power raking provides a lot. A BIG CAVEAT with power raking is that it is not recommended unless the lawn is over-seeded afterwards. Power raking causes a high degree of damage to a lawn; in order to facilitate recovery, over-seeding is necessary.
How to do it – Like a core aerator, a power rake is best rented, rather than owned. The east-west, north-south approach is good for power raking as well, depending on how much thatch needs to be removed. The debris that is pulled up can be composted for a great veggie garden amendment.
When to do it – Since the process is deeply injurious, it’s best to power rake at a time when the lawn is able to recover and you can reseed it. For cool season lawns, this is late April and May or September/October.