Welcome to the latest issue of the Home Lawn Care Newsletter from UMN Turfgrass Science! We will provide up-to-date information to address all your lawn care tasks at the times when you need to know.
October 16, 2023: Issue 16
Fall lawn care
October is a great time to get your lawn ready for success next spring. Here are a few things to focus on as you enjoy the cool weather and beautiful fall colors.
Mulch those leaves!
Mulching leaves with your lawn mower is a good idea for your lawn for many reasons - the mulched leaves can release nutrients to feed your lawn, mulching saves work by having to pick up leaves less often, and the practice may prevent future weeds. As trees begin losing their leaves this fall, mulch the leaves as you mow your lawn to help break them down to receive the largest benefit. However, keep in mind that there can be too much of a good thing when it comes to mulched tree leaf litter on your lawn. Too thick of leaf litter left could slow green-up in the spring, or even make snow mold (a disease of turf) worse. So how do you know when it is time to collect the leaves instead of mulching them? If after mowing you are seeing less than 50% turf cover, it is a good idea to bag when you mow or rake leaves for the rest of the fall.
Instead of raking leaves, try mulching them into the turf | University of Illinois Extension
Good Question: Do you really need to rake all those leaves? | UMN Turfgrass Science
Control creeping Charlie and other problematic perennial weeds
Perennial broadleaf weeds like creeping Charlie, wild violet, or dandelions are easiest to control in the fall, regardless if you’re hand-pulling or treating with an herbicide. Although fertilizing your lawn to increase turf density is a great cultural weed control measure for next year, we don’t recommend using weed and feed type products. Read more about controlling creeping Charlie and other difficult weeds at the links below.
Creeping Charlie | UMN Extension
Creeping Charlie: Management and value to pollinators | UMN Turfgrass Science
Fall lawn weed control strategies | Virginia Cooperative Extension
Control of broadleaf weeds in home lawns | Purdue University Extension and University of Illinois Extension
It’s not too late to seed
The best time for seeding your lawn is from late August until the middle of September. If you’ve missed this window, try dormant seeding. This works well in Minnesota if you are trying to fill in thin turf or even establishing a new area.
Dormant seeding takes advantage of the freeze-thaw cycle over winter and helps ensure seed-to-soil contact, so no soil prep is necessary. Gradually lower your mowing height to 2-2.5 inches as you are mowing your lawn this fall. Then, once temperatures have fallen enough that seed can no longer germinate, you can drop seed onto the ground; this usually happens in Minnesota sometime in late October or early November. The grass seed won’t germinate at these low temperatures, and the soil isn’t quite frozen. Because the seeds are not germinating, neither irrigation nor starter fertilizer are needed until the spring. A germination or erosion control blanket can help ensure the seeds stay in place over winter, especially if there is bare soil or a severely sloped area.
Dormant seeding your lawn | UMN Extension
Purchasing turfgrass seed | UMN Turfgrass Science
Fall’s the time for faster feeding fertilizers
In Minnesota, 1-3 fertilizer applications a year are beneficial to many lawns. Applying ⅓ of your annual nitrogen in the spring and then ⅔ of your annual nitrogen in the fall is a great strategy. If you are fertilizing yet this fall, consider using a fast-release fertilizer.
In fall, slow-release fertilizers may not provide all the nutrients you intend to apply because of cooler soil temperatures and plant dormancy. Many fertilizer products may contain a combination of fast- and slow-release nitrogen sources, so look for no more than 35% of slow-release fertilizer (often labeled as water-insoluble nitrogen) listed on the product label. Quicker release fertilizers like urea are most often taken up in 2-14 days, while slow-release may take a minimum of 6 weeks. You can water before you fertilize (especially during drought) but always water your lawn immediately after fertilizer application.
Fertilizing lawns | UMN Extension
Fall fertilization | Purdue University
It’s time to blow out irrigation systems
Irrigation systems are convenient until something gets frozen. If you haven’t winterized your system yet, don’t wait much longer.
Properly preparing irrigation systems for winter | UMN Turfgrass Science
Irrigation winterization | Iowa State University Extension
Research highlight
Andrew Hollman, a researcher at the University of Minnesota, has been trying out a few different ways to dormant seed new lawns, and so far the results have been great. Read about his work in Investigating dormant seeding as an approach to establish lawns in Minnesota.
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