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.
September 15, 2023: Issue 15
Focus on fertilizer this fall for a healthier, more resilient lawn next spring
While early fall is the best time to do many lawn maintenance tasks, we’re highlighting fertilization in this newsletter.
Lawn care calendar | UMN Extension
Is your lawn ready for fertilizer?
Soil needs some moisture for turf to utilize the nutrients we’re supplying. After a summer with below-average rain, following a couple of years of drought, Minnesota soils are very dry. In some cases, your lawn may be hydrophobic and could actually repel any water you apply. A good soaking rainstorm would help, but otherwise slowly start supplying more water to your soil until the water soaks in deeply before fertilizing.
Now is a great time to fertilize
Early August through mid-October is the best time to fertilize home lawns. It’s easy to remember if you fertilize on Memorial Day and Labor Day. For most lawns, one-third of your annual nitrogen application should be applied in the spring, with the other two-thirds being applied in the fall.
Fertilizing lawns | UMN Extension
How much fertilizer?
We usually determine how much fertilizer to apply based on how much nitrogen the lawn needs. The links below have more detail about this, but most cool-season turfgrasses would benefit from between 0.75 lb. and 1 lb. of nitrogen for every 1000 square feet of lawn. A fertilizer with a grade close to 24-0-12 (%nitrogen-%phosphorus-%potassium) is appropriate for most lawns. If you haven’t done a soil test in the last few years, this fall is a great time to see if any major nutrients are limiting your lawn. The soil test results will include recommendations for the appropriate grade fertilizer and soil amendments for your specific situation.
How to submit lawn and garden samples for analysis | UMN Soil Testing Lab
What kind of fertilizer?
Fertilizers may be synthetic or natural products, both of which provide nutrients to the soil. Synthetics are manufactured while naturals are derived from plant and/or animal products. Natural products may also provide organic matter and be used as a soil amendment. They are mostly slow-release fertilizers providing nutrients over extended periods and are less subject to leaching from the soil. Synthetics can be slow-release or fast-release; typically, look for a synthetic fertilizer with at least 30% slow release (or insoluble nitrogen), which also minimizes the risk of burning the lawn if the fertilizer is not watered-in.
Don’t break the law!
The use of phosphorus on your lawn may be against the law. In Minnesota, phosphorus-containing fertilizers can only be used when (1) a recent soil test shows that your lawn needs phosphorus, or (2) your lawn has been recently seeded or sodded and is still establishing. If your lawn doesn’t meet one of these two criteria, you have little to worry about because phosphorus is generally adequate in most Minnesota soils. Adding unnecessary phosphorus is a waste of money, and excessive phosphorus could lead to runoff and waterways filled with algae and aquatic plants. One important note: natural organic or manure-based fertilizer products often contain phosphorus and are still subject to these restrictions.
2022 Minnesota Statutes | State of Minnesota
What about all the weeds in my lawn?
The UMN turfgrass team spent the 12 days of the Minnesota State Fair answering scores of questions. We received a lot of questions about weeds. Creeping Charlie, knotweed, crabgrass, violets...after a tough summer of high temperatures and little rain, weeds have taken hold of many lawns. Diseases and grub damage have added to the misery. For annual lawn weeds (those that come back from seed each year like crabgrass and prostrate knotweed), fall is the time when they begin to die off, having left behind a myriad of seeds, each one ready to take advantage of a bare spot in your lawn next spring. Proper fertilization of your lawn right now, when our lawn grasses will be growing vigorously, will help keep these annual weeds from taking hold next spring. We recommend that you do not use a weed and feed product on your lawn--focus on fertilization and spot treat problem weeds. Summer annual weeds will be controlled with a pre-emergent herbicide in the spring. You can wait to deal with creeping Charlie and violets in October (more to come in our next newsletter).
Is this plant a weed? | UMN Extension
Managing weeds in lawns | UMN Extension
Research Highlight
One way to reduce the amount of fertilizer your lawn needs is to use a grass that doesn’t need as much fertilizer. We usually refer to this type of lawn grass as one that is “low-input”. How do we know that these grasses truly require fewer inputs? To find out, read “Are low-input turfgrasses really low-input?”
Events
The UMN Turfgrass Science team will be hosting a Lawn Care Field Day in St. Paul, MN on Wednesday, September 27, 2023 from 4:00 - 6:00 p.m. This field day will be perfect for Master Gardeners, homeowners, lawn care professionals, or anyone else with an interest in lawn care.
We will be at the following two events to answer questions on smart irrigation and lawn care as part of our collaboration with the Metropolitan Council.
- Columbus Fall Fest in Columbus, MN on Saturday, September 16, 2023 from 10:00 a.m. - 3:00 p.m.
- Brown's Creek Watershed District Community Event in Stillwater, MN on Saturday, September 16, 2023 from 10 a.m. - 1 p.m.
Have a question on a topic we didn’t cover in this email?
We have resources to answer your questions! Check out these options for even more lawn care information from the University of Minnesota.
We provide research updates, lawn care tips, info about field days, and more at @UMNTurf.