The worst of the summer heat will have subsided soon. Refreshed by the thought of breathing cooler air, you're poised to roll up your sleeves and do some fall lawn care. But you should read these tips first. The regimen right for your situation will vary, according to whether your lawn is composed of a warm season turfgrass or a cool-season turfgrass. If you are unsure which type comprises your lawn, take a sample to your local county extension.
Fall Lawn Care Tip: Find out Your Grass Type
Cool-season turf grasses are so called because they thrive in the cool weather usually associated with spring and autumn. Examples are rye grass, the fescues (both "fine" and "tall" kinds), Kentucky blue grass and bent grass.
By contrast, warm-season turf grasses grow most actively when the weather is warm, which is why they are the preferred grass types of the South in the U.S. Some of their names even make you think "South," as is the case with Bermuda grass and Saint Augustine grass. Other kinds include zoysia grass and buffalo grass.
To be sure, there will be some fall lawn maintenance you'll have to do regardless of the type of grass on your lawn. Let's look at these tasks first:
- Apply herbicides to broadleaf weeds
- Correct soil pH: if your lawn is not performing well, have your soil tested. If the soil test should show a need to reduce acidity, apply lime now. If alkalinity needs to be reduced, apply sulfur.
- Thatch removal: dethatch your lawn, by raking; for bad cases of soil compaction, you may have to employ the technique known as core aeration, for which lawn equipment is known as "aerators" can be bought or rented
- Rake leaves, or use a leaf vacuum, lest the leaves smother your grass over the winter
- Lawn equipment care: make sure to drain old gas out of lawn mowers after the last mowing
The nature of the following fall lawn care chores depends on whether it's a cool season or warm season turf grass that you have to care for:
- Watering during hot, dry spells
- Setting lawn mower height
Fall lawn care for cool season grasses includes ensuring that lawns receive enough fall water to carry them through the long winter. Don't think that because the temperatures outside are no longer consistently high, you can totally forget about watering in the autumn. Overall, you won't need to water nearly as much as in summer, but during hot, dry spells in autumn, remember to provide sufficient water.
Another fall lawn care tip that applies specifically to the maintenance of cool-season grasses is fertilization. Apply 1 pound of nitrogen per 1,000 square feet of lawn. Or purchase a product that has a low, middle number for NPK; for example, Scotts' "WinterGuard" Turf Builder has an NPK of 32-0-10.
Conversely, avoid fertilizing lawns in autumn that are composed of warm-season turf grasses. The latter undergoes a hardening-off process during this time of year to prepare it for winter. Fertilizing warm season grasses in the fall may interfere with that hardening-off process.
So what fall lawn care tasks should you be performing for warm season grasses? By overseeding with annual winter ryegrass (Lolium multiflorum), homeowners whose lawns are composed of warm-season grasses can enjoy a green carpet during the winter, instead of having to look at a brown lawn. But when you buy the seed, be sure to ask for the annual, not the perennial. Annual winter ryegrass will die back when summer's heat returns, turning over the lawn once again to the warm season grasses. This exit is a timely one. The problem with the perennial winter ryegrass is that it doesn't go away, competing with your warm season grasses for sunlight, water, and nutrients.
Lawns composed of cool-season grasses can also profit from overseeding. But in this case, the motivation behind overseeding lawns is not winter cosmetics, but to fix bare patches―with an eye to next year's lawn.
Adjusting Mower Height for Fall Mowing
Adjusting lawn mower height for fall mowing is not an issue with cool season grasses. Just set the height as you normally would, right up until the time when growth stops, and you stop mowing. But an adjustment should be made to lawn mower height in the fall for warm-season turf grasses: increase the height by 1/2 inch.
So at exactly what height should you set lawn mowers, in general? According to Robert E. Kozlowski at the Cornell University Cooperative Extension, mowing your lawn with a lawn mower set at a proper height can save you from having to rake or bag your lawn clippings. His rule of thumb is, "Mow when your grass is dry and 3 to 3-1/2 inches tall. Never cut it shorter than [sic] 2 to 2-1/2 inches or remove more than one-third of the leaf surface at any one mowing."
Kozlowski's premise is that the valuable nutrients in the grass clippings can do your lawn some good, left right where they lie after mowing―as long as their bulk is kept at a minimum. By following his rule of thumb and cutting only about an inch off the top of your grass at any one time, the bulk of the grass clippings is kept low.
Employing Kozlowski's lawn care tip will entail more frequent mowing, to be sure. But the result will be a healthier lawn, fed by nutrients that you would otherwise be hauling away. Think of it this way: with Kozlowski's approach, you're essentially mowing and fertilizing at the same time, taking care of two lawn maintenance tasks at once―that works for me.
Some useful lawn equipment to perform this task is the mulching lawn mower. With mulching lawn mowers, you do not need to be quite so careful about the height at which you cut your grass since the clippings are shredded up more finely. This works much better for those of us who do not generally walk around with tape measures on our belts.
How Long Into the Fall Season Should I Continue to Mow the Lawn?
Those of us who despise mowing can't wait to retire the mower for another year. But do not be too hasty. Nor should you think that, just because you stopped mowing last year on such-and-such a date, the same end-date will be valid this year.
This question is a lot easier to answer than you might imagine, though. Simply continue to mow the lawn until the grass stops growing! Weather will determine this, not some artificial deadline.