Fall Lawn Care Tips
The heat of August may not feel like fall is right around the corner, but the days are getting noticeably shorter and soon it will be time for PSL’s, football, and hoodies. Fall is arguably the most important time of year for lawn care, most notably on cool-season lawns. If your lawn has taken a beating from summer stress, the fall is a great time to repair and also prep your lawn for success come spring. As fall lawn care goes, cool- and warm-season lawns require different practices to ensure their continued success. But there are also some commonalities between the two.
Here’s a list of things to take care of from mid-August through October.
Fall fertilization can be beneficial for cool and warm-season lawns alike. For warm-season lawns, avoid applying nitrogen after the beginning of October or possibly earlier, depending on how far north you live. If your warm-season lawn is deficient in potassium, the fall is a great time to apply a potassium-heavy fertilizer to help your lawn prepare for the stresses of winter. A product like Simple Lawn Solutions 0-0-25 will provide plenty of potassium without the nitrogen, which is unnecessary at this time. Another low-nitrogen product to consider for your early-fall, warm-season fertilization is SLS 3-18-18, especially if your lawn is deficient in phosphorus.
For cool-season lawns, this is the time to really get some products out there. Some experts suggest that up to 2/3 of the total nitrogen applied to a cool-season lawn should come in the fall, once in September and again before November. Consider a product like Simple Lawn Solutions 28-0-0 to help meet the nitrogen requirements of your recuperating cool-season turf. 15-0-15 and 16-4-8 are both products that can supply your lawn with nitrogen and potassium, great for fall fertilization of cool-season lawns.
Fall Weed Prevention
Fall is an awesome time to control weeds. This can be done with pre and postemergence herbicides. If you are wondering how to control weeds like dandelion, wild violet, ground ivy, plantain, and thistles, consider fall your optimum window for control. As the days start getting shorter and temperatures cooler, these broadleaf weeds begin sending food and nutrients down to their roots to be stored for winter. This can make applications of selective broadleaf herbicides labeled for control of your specific problem weed extremely effective as the herbicide can be translocated throughout the plant and stored down in the roots.
In addition to existing weed control, weed prevention can happen in the fall, as well. Weeds like henbit, chickweed, deadnettle, and annual bluegrass germinate in the early fall, grow throughout the winter and into the spring, and prior to the summer heat, they set seed and die, only to continue this cycle again next fall. Using a pre-emergence herbicide during the fall is a great way to combat this. Preemergence herbicides create a barrier in the soil that prevents weed growth immediately upon germination, they do not prohibit germination. Preemergence herbicides have a residual time in which they’ll stay adsorbed to the soil and be available for plant uptake, but once that window has passed, they’re no longer effective. Timing your preemergence herbicide application just before the soil temperature drops back below 70 °F in the fall is a good benchmark. Another strategy that can lengthen your window of control is to make a split application and apply half the labeled rate early in the fall and the other half later in the fall. Whatever method you choose aim to apply before soil temps drop below 70 °F for consecutive days.
Is leaf clean-up necessary? Leaf removal is very important to the health of your lawn. Leaving a thick layer of fallen leaves on the canopy of your lawn will block sunlight from reaching the leaves of the turf. If left all winter, layers of leaves can retain moisture near the soil surface, which may increase disease incidence over the wintertime.
For this task, forget raking and use the mulching capability of your mower to break the leaves into tiny pieces that won’t choke out your lawn. Mulching leaves into your lawn and soil adds free organic matter and nutrients. Mulching sugar maple leaves has been shown to decrease dandelion populations. Your regular mower with the discharge chute closed will do a good enough job, but you can also buy a special mulching blade for your mower to increase the effectiveness. Raking might come into play if you just have too many leaves to be broken down effectively by your mower alone. Make sure to save some leaves for your mower to break down and provide a free soil amendment to your lawn.
How should you mow your lawn during fall? For cool-season lawns, the fall is their time to shine. Hopefully, during the summer months, you raised your mower’s height of cut to increase leaf area and consequently increase the photosynthetic capacity. Fall may be a good time to go ahead and slowly drop the mowing height to something you’re comfortable with. A lower stress time for your lawn is perfect for dropping the height of the cut for a tight-looking lawn. A lower mowing height on cool-season lawns in the fall can help open the turf canopy and allow oxygen exchange during the winter months. Leaving a lot of lush leaf growth going into the winter can increase winter disease severity. A lower canopy is also advantageous for fall overseeding of your cool-season lawn to thicken up any thinning areas that took a beating during summer.
Warm-season lawns, at this time, would appreciate it if you raised the mowing height going into fall. This goes back to the principle of increasing leaf surface area to maximize photosynthesis. As the days get shorter, your lawn will be storing more carbohydrates to prepare for winter and a jump start the following spring. Maximizing your warm-season lawn’s photosynthesis means more stored energy to help your lawn make it through the winter unscathed.
Fall Lawn Diseases
How can you prevent lawn diseases in the fall? Cool-season lawns need to be prepared for snow molds (Typhula and Microdochium) and warm-season lawns for large patch (Rhizoctonia) and Spring Dead Spot (Ophiosphaerella). Pink snow mold (Michrodochium nivale) is most severe when heavy snow blankets your lawn for long periods, but snow is not required for its growth. If pink snow mold is a problem at your house, drop your mowing height in the fall and reduce your late-season nitrogen fertilization. Group 3 or 11 fungicides can also be applied prior to snow cover for pink snow mold control. Gray snow mold is also severe under heavy amounts of snow that lay undisturbed for long periods. Leaving a lush, heavily fertilized lawn going into the winter can increase susceptibility. Group 3 and 11 fungicides are also applied preventatively in late-fall prior to snow cover.
Large patch (Rhizoctonia solani) occurs on warm-season lawns in the shoulder seasons of fall and spring. It becomes active after soil temps drop below 70 °F. Excessive nitrogen applications during the fall and heavy thatch on warm-season grasses can encourage large patch development. Preventative applications of group 3, 7, or 11 fungicides, when soil temps drop below 80 °F for centipede and St. Augustine lawns, and 70 °F for zoysia. Control can be difficult and inconsistent between years. Spring dead spot (Ophiosphaerella spp.) is a fungus that attacks roots, stolons, and rhizomes of bermudagrass making them very susceptible to cold injury. It becomes evident in the spring as small patches of dead turf, but the infection actually occurs over the winter. Predicting spring dead spot emergence is rather difficult. Fungicide applications of group 3, 7 or 11 products made in the fall with soil temps below 80 °F but above 60 °F, and watered heavily are a great preventative measure.
Cultivate (cool-season only) – The two forms of cultivation we are referring to are core-aerification and verticutting (vertical mowing). It may seem counterintuitive to beat up a lawn that is just now recovering from the heat of the summer, but the fall is an awesome time to aerify your lawn. Core-aerification removes plugs of soil and thatch and brings them up to the surface to either decompose or be collected and removed. Aerification can help reduce soil compaction, reduce thatch, and introduce oxygen to your long-suffering roots. If your lawn is suffering from heavy thatch build-up, first consider reducing your fertilizer use or check your soil pH to make sure it’s below 8 and above 5. A well-managed, properly functioning lawn ecosystem should allow for proper thatch degradation, which does not result in an unacceptable build-up of thatch. If you do decide that verticutting is necessary, the fall is a great time to take care of this. You should be able to rent an aerifier or verticutter from your local hardware store, or you can pay a local lawn care company that offers these services to come and perform them on your lawn.
Seeding the Lawn in Fall
Your freshly aerified or verticut (or both) lawn is primed for seeding and soil amendments. Now that the turf canopy and soil are open, it’s a great time to work products like Sea, Soil, and Root Hume into your soil. For these products to be beneficial, habitual use works best. They are not as effective when used in isolated, reactionary applications to heat or drought stress. Work them into your soil during the fall and spring so you can reap the benefits come summer.
Seeding (cool-season only) – This should be done after aerification so as not to disturb your freshly sown seed. But hopefully, your fall fertilization, soil amending, and aerification have made your lawn a 5-star seed bed, ready to facilitate germination. If you’re choosing to overseed your thinned-out cool-season lawn, make sure to lower your mowing height prior to seeding because you’ll want to stay off the lawn for at least 3 weeks after sowing your seed. It will also help the seed move lower into the canopy for better soil contact. Because this is a list of things we think that you should be doing in the fall, we will omit fall overseeding of dormant warm-season turf. It is an option if you don’t want to stare at straw-colored dormant turf for 5 months, but not something that is mandatory.
In conclusion, making sure that you address all these items starting in early September will go a long way towards a thriving lawn. A happy issue-free lawn come spring starts in the fall. Contact us today for a free lawn plan or take our product quiz to find out what products will work best for your specific situation.