This week, in mid-season, my club is aerifying, closing the golf course for the week. I’ve always wondered about what, exactly, the process is for, why it’s done at certain times and where on the golf course it’s required. Thus, I went to my good friend and agronomist extraordinaire, Terry Buchen of Golf Agronomy International to learn more about this often frustrating process which disrupts the golf season, often when we think the greens are just getting to their best. Depending on whether the golf course has their own equipment or not, either the grounds crew will perform aerification, or the job will be contracted to a third party. Obviously, the first question is WHY do we aerify and deal with the disruption and temporary compromised conditions?
Buchen says: “Removing excessive amounts of thatch & organic matter (OM), reducing compaction and providing more air to the soils below. Ultimately there should be a 50% Air and 50% water mixture in the soils for the roots to breath properly. OM is usually being produced much faster than it is being removed and golfers would not tolerate having aerification being done frequently enough to keep up with its growth.” Since it always seems as though aerification is done at the most disruptive times, I asked how frequently it’s needed. The most important thing is that aerification is done when the turf is growing fully. That means in the north, with “cool-season” grasses, in late spring (after the Poa Annua dies out) and late summer, when it’s a bit cooler (hopefully) but allowing enough time for the holes to heal before winter. In the warmer southern climates, Buchen suggests 2-4 times during the summer off-season spaced about 4-6 weeks apart. He says tees, fairways and roughs should follow the same schedule as greens, north or south. In transition-zone climates, it can vary depending on the type of grass, elevation, winter climate and other factors.
Many of us have heard about various types of “tines” used in aerification. Buchen explained that there are solid “Pencil” tines that poke holes but don’t remove any cores. These range from 1/8″ to 1/4″ in diameter and typically from 4″ to 6″ in length. There are also solid tines that don’t remove cores ranging from 1/4″ to 1″ in diameter and from 4″ to 10″ in length. Coring tines remove a core and are hollow. They range from 1/4″ to 1″ in diameter and from 4″ to 10″ in length.
The larger the tines, the more excessive OM is removed, along with other benefits. The deeper the tine, the more soil is removed and the more modified soil (topdressing) can be introduced.
One of the primary concerns of aerification is scheduling. Buchen strongly advises that clubs, in consideration of their climate, schedule aerification first based on the agronomics and then plan major events (member-guest, club championship, etc.) around that schedule. Regardless of climate, aerification should be scheduled so recovery can occur during a season when the turf is fully growing. Even in Florida, Buchen says they aerify during the summer months because the warm season grasses are in full growth mode. Thus, in southern climates, less disruption occurs. Most superintendents hope for dry weather during the process to expedite both “punching” and healing.
Buchen says that the typical recovery time is 2-4 weeks, depending on a number of variables, such as soil temperature, fertilizing prior to aerification and the size, depth and spacing of the holes. He recommends fertilizing 7-10 days prior to aerification as one way to speed the healing process.
Even though most golfers loathe aerification, the bumpy and slow greens it leaves behind (temporarily) and at some courses closure for up to a week or so, the risks of not aerifying, according to Buchen include excessive thatch buildup, softer playing conditions and unhealthy turf, resulting in the need to regrass sooner than normal. Compaction continues to increase on the soils below. This can become problematic and costly.
Aerification is like the old Fram Oil Filter commercial says, “pay me now or pay me later”. It’s usually best to do it now and take care of what we have rather than experiencing poorer quality conditions and more frequent replacement, which not only becomes more costly but impacts the value of the property and can result in longer disruptions.