Core aeration or aeration is a physical process that utilizes a heavy machine called an aerator. Similar to a garden rototiller, the aeration machine has a central shaft with 4 or 5 discs where the actual aeration tines are attached. There are several types of aerators: some utilize solid tines while others are hollow, allowing the machine to extract plugs as it drives over your lawn. These tines are designed to penetrate your lawn like using a cutter for cookies. Most aeration cores will vary between ½” and 1” in diameter and will be left on the surface of your lawn. The depth of a good core aeration job should vary between two and three inches. Core length is dependent on soil moisture, the weight of the machine and its ability to push down versus roll over compacted soil, as well as the age or length of the tines. Older tines become worn and must be replaced as they do not have the capacity to penetrate the soil with a blunt or worn tip. If you are considering a rental aerator, be sure to check the tips of the tines – the more pointed they are, the better. A blunt tine or one with a worn down tips will simply not pull a decent plug, although you may enjoy the exercise!
An aeration machine’s effectiveness is also dependent upon the weight of the unit and the speed at which is it used over the lawn. The faster the aeration job, the less likely the machine’s weight can push down, forcing the tines into the soil. In addition, most rentals are smaller, older units, enabling the average home owner to utilize the machine on a given weekend. Although these rental units may do an adequate job in terms of maneuvering given their shorter width, a commercial grade aerator weighs hundreds of pounds more and is strapped with not only weights, but also with a drum full of water. Basic physics dictates that using the right tool for the job, in this case a commercial aerator, will provide superior results.
Aeration can be done any time of the year, but typically it is done in the spring or fall when soil moisture is greatest to ensure good plugs. In addition, fall is the best time of year to over seed a lawn due to warm temperatures and more importantly, the absence of annual weeds like crabgrass that often interferes and reduces results. Overseeding introduces superior grass varieties after an aeration job. The seed germinates primarily in the aeration holes just like doing a hair transplant. Overseeding is not meant to fill in damaged lawns with large patches or bare areas: this would be more in line with topdressing and seeding that could be done in conjunction with an aeration job. Topdressing adds soil or compost in a thin layer allowing germination to take place in bare sections. Overseeding adds new grass to an existing lawn area and small bare spots, and helps thicken up an existing lawn or thin areas. Aeration and overseeding is not meant to establish a lawn or repair significant damage without the use of topdressing or lawn restoration. Aeration is a great process and should be done annually to help maintain good soil health while minimizing compaction.
What are the benefits of Aeration?
- Increased moisture penetration since the holes open up space for rain to reach the root system below. The surface of the soil is hardened from high heat and summer drought, and a lack of rain makes the surface of the lawn much harder to loosen up due to the baking action of summer heat.
- Increased oxygen exchange (important for healthy roots) especially in compacted and dry soils. Punching holes in the lawn will physically allow air to reach into the surrounding root systems, even as the hole begins to break down and fill back in with soil next spring.
- Reduces soil compaction (especially soils high in clay) caused by those summer parties or high use. Compacted soil does not promote healthy roots in grass or trees for that matter.
- Increases penetration of fertilizers and other lawn products due to the holes being made. The pellets or flakes simply roll into the plug and dissolve for faster results.
- Increases rate of thatch decomposition due to micro-organisms being brought up to the surface in the plug itself. There is no need to rake aeration plugs off a home lawn as they breakdown on their own in a short period of time.
- Increases root development due to the vacant space created by the aerator tine. The turf roots can expand outward and beyond in search of water, air, and nutrients in the soil.
If you don’t have aeration scheduled this year, give us a call and we can give you a proposal on aeration, as well as overseeding. If topdressing is necessary, we can also give you recommendations on this procedure. Aeration typically begins in mid to late August and runs right into October. If you are interested or have questions on this important process, be sure to give us a call or e-mail anytime. It will be back to school time before you know it! Be sure to watch our aeration video posted on Flickr located on the home page of this blog.