That Set You Up for a Bad Spring

Home owners tend to turn their attention away from their lawns as autumn arrives. Grass growth slows, and preparing the home itself for the coming cold months seems like a greater priority. But autumn is a crucial time of year for grass. Make a lawn-care mistake in the fall—as many people do—and it could cause problems for the entire next year or longer.

Eight autumn lawn-care mistakes to avoid…

Leaf-Removal Mistakes

Mistake: Letting fallen leaves accumulate. Many home owners do not bother raking or blowing until nearly all the leaves are off the trees. But grass needs lots of sunlight to thrive, and the longer that leaves linger on your lawn, the less light gets through. Light-starved grass soon begins to weaken and die, creating an opening for weeds that will dog you in the future.

Better: Remove leaves whenever they cover your lawn to such a degree that you see more leaves than lawn. Also, rake whenever rain is in the forecast—dry leaves tend to blow around enough that the lawn below still gets some sun, but wet leaves mat and remain in place. (And wet leaves are much harder to ­remove.)

Mistake: Inadequate leaf mulching. Some home owners run a mulching mower over fallen leaves and let the cut-up pieces remain on the lawn, thinking that these mowed leaves are like mulch that will help—or at least not hurt—the lawn. It’s true that mulched leaves can be beneficial for topsoil. But it is vital that most of the mulched leaf pieces get down into the lawn rather than remain on top where they continue to prevent sun from reaching the grass blades.

Better: Visually inspect your lawn after you run your mulching mower over fallen leaves. If the lawn’s color is closer to the brown of the fallen leaves than to the green of grass, run the mulching mower over the lawn a second time—or as many times as it takes to break them up.

Grass-Care Mistakes

Mistake: Using a fertilizer not specifically designed for fall. Fertilizing in the fall is tremendously beneficial for a lawn—it helps the lawn survive the winter by encouraging enhanced root development and carbohydrate production and storage. But if you use any old lawn fertilizer that happens to be lying around your garage or on sale at a store, this fertilization could mostly stimulate “top-growth”—that is, the visible blades of the grass could become taller. That’s a problem, because if grass blades are growing significantly in autumn, they are not “hardening off”—­undergoing the natural changes that help grass ­survive the cold of winter.

Better: Use a fertilizer specifically designed for autumn. All the major fertilizer makers offer these. Granular fertilizers are better than liquid fertilizers in fall—if there are any leaves on your lawn when you fertilize, granular fertilizer will roll off those leaves and into the lawn…while liquid fertilizer can stick to leaves and then get raked away. Fertilize before your lawn changes from its usual green to a browner winter tint—in most parts of the country, it’s safest not to wait past mid- to late ­October. If you wait too long and your lawn is already brown, skip fall fertilization. When a lawn turns brown for winter, it stops taking in nutrients. At this point, spreading fertilizer is not only a waste of time and money, it could be environmentally harmful—the chemicals in the fertilizer will not be absorbed by the dormant winter grass, so they could leach into groundwater.

Mistake: Overwatering. Mother Nature typically provides most or all of the water a lawn needs in autumn. Providing more water than a lawn needs as winter approaches could prevent the grass from hardening off to protect ­itself.

Better: Lawns do best when there is a gentle weaning off from summer ­waterings. As temperatures start to drop, gradually reduce the amount of water you supply. By October, you probably should water only if there is an exceptionally warm, dry spell. (This can vary based on climate, amount of direct sunlight and other factors. Consult a local garden shop, lawn pro or university agricultural extenion if you want a more localized end-of-season watering schedule.) If you have an irrigation system, stop running your preset summer watering schedule and instead turn on the system only as necessary.

Mistake: Cutting grass lower for fall. Some home owners lower their ­mower-blade height in autumn because it is easier to rake leaves off short grass. This also lowers the odds of winter “snow mold” problems (from moisture trapped beneath lingering snow).

But when you cut grass blades short in autumn, you rob them of their capacity to convert sunlight into nutrients—nutrients they must store to survive the winter. And because grass blades do not grow very quickly in autumn, they cannot easily recover from being cut low.

Better: Mow your grass the same height in the fall that you do throughout the spring and summer—the advantages of mowing shorter are not worth the potential for long-term damage.

Procrastination Mistakes

Mistake: Delaying aeration until spring. Running a core aerator over your lawn every few years is among the best things you can do for it. The aerator creates small holes in the soil that allow more air and moisture to get down to grass roots. The trouble is the timing—many home owners aerate in spring or summer, when their attention is on their lawn. Depending on what type of grass you have, that might be a mistake.

Better: If you live in the northern US, you almost certainly have a cool-season grass such as Kentucky bluegrass or ­fescue. If so, early fall is the best time of year to aerate. Why? Aeration is great for your lawn in the long term, but in the short term it wounds it. Early fall is when cool-season grasses are best able to recover, in part because there is less competition from crabgrass and certain other common weeds.

Late spring or early summer is the best time to aerate only if you have a warm-season grass such as St. Augustine or Bermuda grass, which is likely if you live in a warm part of the US. (If
you are not certain what type of grass you have, bring a sample to a garden center or university agricultural extension.)

Mistake: Leaving thinning or bald spots until spring. Waiting to address these common lawn issues will hurt you. By spring, opportunistic weeds might have gained a foothold in these problem areas.

Better: In late August or September, apply one inch of topsoil to all bald/thin areas and then spread grass seed. Gently step on the areas to press the seed into the soil. Check these thin/bald spots in the spring, and add additional topsoil and seed if the lawn there remains thin.

Mistake: Allowing dandelions to take hold. Home owners generally think of dandelions as a late-spring problem because that’s when the bright yellow flowers appear. But the dandelion plant actually starts growing during the prior autumn (as do “winter annual” weeds such as common chickweed and annual bluegrass). Home owners fail to notice them because the young dandelion plants are green like their grass.

Better: If dandelions frequently appear in your lawn in the spring, ­apply a weed killer specifically designed to control them in autumn, when the dandelions are young and vulnerable. Follow the directions on this weed killer precisely.

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