With autumn approaching, we will begin seeing cooler daytime and evening temperatures, along with (hopefully) more predictable rainfall patterns.
The cool-season turfgrasses growing in our lawns will be recovering and trying to fill in any bare spots from summer stress as we move into their more preferred growing conditions. At the same time, summer annual plants like crabgrass or foxtail have begun to set seed before withering away. Perennial weeds like dandelion or creeping Charlie will still be hanging around but have spent their resources flowering throughout the summer.
This is the best time of the year to encourage a healthy lawn next year through proper fertilization and weed control.
Most lawns would benefit from some nitrogen from fertilizer. This nitrogen will be used by the turf plants to fill in any thin or bare spots, as well as take back some of the space filled in from summer annual weeds.
Lawns also will use this nitrogen to develop a deeper root system, preparing it for any dry periods next year.
Prepare for drought
With the past three years of excessive heat and summer drought in a row, many lawns have suffered. Consider this a great opportunity to update any bare areas with a new and improved cultivar or species that will be better adapted for future stressful summers. Overseed with more drought-tolerant turfgrasses like fine fescues or turf-type tall fescues.
Now is a great time to re-establish dead areas by overseeding. In some cases, you may want to rake to remove any dead or bare soils to encourage better seed-to-soil contact. But, as we are in an El Niño year, which is typically drier than normal, it may be a good idea to keep some seed for dormant seeding areas where there is poor germination and emergence this fall.
Control broadleaf weeds
Summer annuals like crabgrass and foxtail will be dying off shortly, so you don't need to try and control them now. But perennial broadleaf weeds like dandelion, creeping Charlie, wild violet, Canada thistle, or yellow woodsorrel are still going to be growing and developing. Now is the best time to try and control these perennial plants through selective herbicides like 2,4-D, triclopyr or dicamba, which will not harm the turf plants.
The best weed control method in lawns is a dense and healthy turf that has few places for invasive weeds to encroach.