It’s been a while since we talked about fall yard care on the MWMO blog. While parts of our website offer plenty of information about what we want you to do this time of year, it occurs to me that we haven’t always done a great job of explaining why.
With the official arrival of fall and the turning of the leaves, we thought now might be a good time to get back to some basics. Read on to find out why it’s so important to properly dispose of your leaves and get your yard prepared for the winter, and why what’s good for your yard is good for our waters.
The Problem: Excess Nutrients
Why does an organization focused on water even care what people do in their yards in the fall? In a word: “Nutrients.”
Leaves are packed with nutrients like phosphorus and nitrogen. When trees shed their leaves in the fall, they restock the earth below with the raw materials that plants need to grow and thrive. Normally, this is a good thing. Leaf litter becomes habitat for insects and other wildlife, and the decomposing leaves fertilize the soil.
In urban areas, however, something different happens. Hard surfaces like streets, parking lots and buildings prevent the nutrients from entering the soil. The fallen leaves begin to pile up along curbs and in the streets. When it rains, all that nutrient-rich leaf litter is washed through the stormdrains, which carry it directly into nearby bodies of water. (In our watershed, most of this material goes directly into the Mississippi River.)
In the water, nutrients from all these decomposing leaves promote algae growth, which starves the water of oxygen, killing fish and ultimately disrupting whole ecosystems. It may seem hard to believe that leaves from the tree in your yard are contributing to water pollution, but it’s true. This is why we spend so much time promoting good yard care practices.
But there’s a side benefit to managing your leaves properly: it’s good for your yard too. Good fall yard care practices lead to greener, healthier lawns and landscapes. This in turn helps reduce problems like erosion, which is another source of water pollution. So you can feel good about putting a little extra work into your fall yard.
Rake, Mulch or Compost? What You Should Know
We know why letting leaves pile up in the streets is a bad thing. But letting whole leaves pile up on your lawn is also bad. Why? For one thing, leaf litter forms a soggy, decaying mat that can smother your turf, exposing it to mold and disease. More importantly, a lot of those leaves will get blown into the streets, clogging stormdrains or washing into stormsewers.
You’ll want to pick a strategy to properly dispose of your leaves. Rake, mulch, compost them — or use some combination of all three. It doesn’t matter how you do it; just pick the option that works best for you and your yard.
We should also mention that it’s okay to leave behind some leaf litter as insect habitat in places like gardens, where it’ll stay put and won’t cause any trouble.
Raking leaves is a time-honored fall tradition — loved by some and loathed by others. For many, it’s the simplest, cheapest, or only option. The only supplies you’ll need are a rake, some yard waste bags, and some free time. Many cities offer curbside pickup of yard waste, which makes proper disposal a breeze.
The biggest mistake people make is stopping where their lawn meets the curb. Do the environment and your block a big favor by raking up the leaves that fall in the street as well. Don’t assume that the street sweepers can time leaf pickup around weather events. In the fall, snow may prevent city equipment from picking up leaves. And, in the spring, the first good rainstorm will send them into the stormsewers. Be aware that stormdrains clogged with leaves can also cause localized flooding during a rain event. By raking or sweeping leaves out of stormdrains on your street, not only are you keeping water bodies cleaner; you’re also protecting property in your neighborhood.
Finally, if you’re using the city’s curbside pickup service to get rid of your leaves, make sure you check to see what date the service ends. Otherwise you’ll be stuck with bags of dead leaves that you’ll have to store over the winter or haul to a disposal site yourself.
Recently, experts have begun advocating for mulching leaves rather than raking and bagging them. In addition to being faster and easier than raking, mulching keeps your lawn healthy by fertilizing it. (Mulching your leaves with a lawn mower is equivalent to adding a round of fertilizer to your soil every time you mow.)
From an environmental perspective, mulching is also good because it chops up the leaves into small bits that are held in place by the turfgrass while they decompose. This keeps them out of the streets and away from stormdrains. Just make sure you mulch regularly. That way leaves won’t pile up to a point where they’re too thick for your the mower to handle them.
A good rule of thumb: If your lawn looks like it’s more than 50 percent covered by leaves, consider raking and bagging them instead of mulching. And again, don’t forget about all the leaves in the street. Rake them onto your lawn and mulch or bag them too.
Finally, composting presents yet another solution for disposing of leaves — one that provides you with a useful material you can use for gardening and landscaping.
The science of composting is too large to delve into here. For those interested in learning more, the Minnesota Pollution Control Agency devotes a whole section of their website to backyard composing. Clean Water Minnesota also put together a handy downloadable guide that covers the basics.
Setting Up for a Healthy Spring Yard
Leaves aren’t the only thing you should think about in the fall. If you’ve got bare patches on your lawn to fix, or if you’ve been thinking about installing some new native plants as pollinator habitat, fall is the right time of year get it done. Best of all, you can accomplish these things using simple, organic methods that avoid the use of expensive and potentially harmful chemical fertilizers.
Fall is generally the best time for planting grass in Minnesota. The season’s moderate temperatures help the seeds germinate at the same time established plants and weeds are going dormant, which gives the new seedlings a better shot at survival.
Fixing bare spots in your lawn should be a priority. In addition to making your yard look better, growing new grass in bare patches helps prevent soil erosion. This helps keep sediment — another common water pollutant — away from stormdrains and waterbodies. Try to plant hearty grass varieties that will grow well in your yard’s particular soil and lighting conditions. The University of Minnesota Extension offers a good overview of the seeding process for repairing patchy lawns, and Clean Water Minnesota has a handy tip sheet on organic lawn restoration (PDF).
On the other hand, if you’re sick of caring for your turfgrass and not interested in planting more of it, fall is also a great time for installing native flowers, grasses, shrubs or trees. In addition to providing much-needed habitat for pollinators, mature native plants take less watering and are great for managing stormwater runoff. We’ve got an overview of the benefits of native plants here, along with some links that will help you get started planting them. You might also consider enlisting help from a Master Water Steward, who can help you do some basic native landscape planning.
One of the simplest ways to strengthen your lawn is by aerating it, and fall is the perfect time of year to do it.
Aeration involves punching small holes in your yard. It loosens compacted soil and helps to circulate air, water and nutrients in the ground. This leads to a healthier lawn that will require less fertilizer and other chemicals to maintain. You don’t need to aerate every year; once every couple of years will do.
You can aerate small areas by hand with a shovel or a spading fork. For larger areas (like entire lawns), you can rent a self-propelled core aerator from your local equipment rental shop for around $40–$50. Water your lawn the night before, to help loosen the soil. And don’t worry about the little plugs of dirt and grass it leaves behind; these will break down over time.
What About Fertilizer?
Fall is also the traditional time of year to apply chemical fertilizer to one’s lawn. Unfortunately, fertilizer (like leaves) is a major source of excess nutrients in our waterbodies. Due to its environmental impacts, we generally advocate for avoiding the use of fertilizer — or at least using as little as absolutely necessary.
If your turfgrass is in rough shape and you think you need fertilizer, try using organic lawn care methods first. Choosing the right grass seed and planting it properly, combined with practices like mulching, aeration and other smart lawn care techniques, may be as effective or better than expensive chemical fertilizers.
If organic lawn care methods don’t seem to do the trick and you think you might need fertilizer for your turfgrass, consider having the University of Minnesota test the soils in your yard before you buy any product. The test is inexpensive, and you’ll get great information on what kind of fertilizer will work best for your lawn. If testing indicates that you do need fertilizer, choose zero-phosphorus fertilizers that are better for the environment. Also, avoid weed-and-feed combinations, which may include chemicals that won’t treat the type of weeds in your lawn or might not keep grass healthy in your particular lawn conditions. Instead, choose products that kill specific weed-types you’re dealing with or address lawn issues in your unique situation.
Share Your Tips
What are you doing this fall to keep your yard healthy and ready for spring? Anything that prevents water pollution, too? Sound off in the comments.