As fall rolls around, heat and drought have taken their toll on most lawns. Lower temperatures and rainy days provide some relief, but with winter just around the corner, many homeowners ask themselves, “Why should I worry about my lawn now?”
There’s no one-size-fits-all answer, but northerners, southerners, and those in the transition zone (more on that in a minute) need to get out the fertilizer, weed and feed, rake, mower, and, in some cases, dethatcher.
Lawn Belts and Types
Grass in the United States is usually divided into two types based on how it grows: cool season and warm season. Cool-season grasses include annual and perennial ryegrass, creeping bentgrass, creeping red fescue, hard fescue, tall fescue, orchardgrass, and Kentucky bluegrass.These all begin to grow when the soil temperature reaches 40 to 45 degrees and will exhibit active growth in early spring and fall when the temperatures are in the 65- to 75-degree range. They usually go dormant in temperatures over 90 degrees and may even turn brown during a particularly brutal heat wave. They need plenty of water during the summer months but are significantly more cold-resistant than their warm-season counterparts.
Warm-season grasses include St. Augustine, Bermuda grass, Bahia grass, buffalo grass, carpetgrass, centipede grass, switchgrass, and zoysia. These grasses start to grow when the soil temperature reaches the 60- to 65-degree range and tolerate, and even thrive, in temperatures of 90 to 95 degrees, which means they see their best growth in summer, and they will go dormant in winter, when temperatures fall below 50 degrees and can die if temperatures remain too low for too long.
On the upside, they are more drought-tolerant and need less water during the summer than their cool-season cousins.
It would seem logical that the northern half of the country would use cool-season grass and the southern half would use warm-season grass, but there is a transition zone that runs from mid-to-southern California, through northern Texas to Virginia, and up into southern New Jersey. Instead of having the best of all worlds, transition zone residents tend to have summers that are too hot for cool-season grasses and winters that are too chilly for warm-season choices.
Perennial ryegrass, tall fescue, and Kentucky bluegrass tend to be the most resilient. If you’ve been doing everything right but the lawn is dreadful, you may have the wrong grass. Fall is an excellent time to consider changing your grass type.
Height and Nutrition
The rule of thumb for northern lawn-owners is to mow until the grass stops growing, which typically happens in late October through November. There’s a debate about whether, during the last mow of the season, the grass should be cut by one-third (four inches to two and a half) or even half (four inches to two inches), or if it should be cut at its regular height.Proponents of mowing short say it stops the grass from laying over underneath snow, helps to prevent the resulting formation of mold and fungus, allows more sunlight to reach the soil, and deters voles from digging tunnels. Proponents of leaving the grass at its normal height say it prevents weeds, leaves the root length longer and healthier (as there is a direct ratio between grass height and root length), and simply looks better. The decision is up to you.
Another decision is whether to rake up leaves, moss, and other debris from the lawn, or run it over with a mulching mower to turn into an organic fertilizer. For those with many trees, snow on the horizon, or any other concerns, it may be best to bag them or add them to the compost pile; otherwise, they can stick together into a grass-smothering layer.
If you didn’t fertilize at the end of summer, that’s fine. Wait until the grass stops growing, as fertilizing afterward results in strong root growth and early green-up come spring. This is also a good time to apply a broadleaf herbicide (aka weed killer), particularly if your lawn is prone to noxious winter weeds. Or opt for a weed-and-feed suited for the lawn type.
365 Green
Southern gardeners have it both easier (fewer fall chores) and harder (they need to keep mowing, though the growth does slow a bit). Rake and mulch leaves by running over them with a mulching mower. Aerate the soil, particularly before applying fall fertilizer or weed and feed for the best results. Fall is also a good time to re-sod bare spots or overseed with a cool-season grass such as ryegrass to keep things green during colder temps. Note: Zoysia doesn’t like overseeding, and some weed-and-feeds may kill new grass seeds.No matter where you live, if it hasn’t rained or snowed in three to four weeks, water the lawn.
