With lawns damaged by last summers’ heat and drought stress, seeding to repair thin or bare areas may be needed. It might seem a little early to talk about seeding lawns; however, I have had questions about dormant seeding and drought tolerant grasses to use.
If lawns are thin or have bare areas that need seeding, start planning now. Late summer is the best time to seed cool season grasses like Kentucky bluegrass and tall fescue; however, most people will not want to wait until September to repair a damaged lawn. May into June is when warm season grasses like buffalograss need to be seeded.
Other seeding times for cool season grasses are dormant or spring seeding. Dormant seeding is done when soil temperatures are below 40 degrees Fahrenheit and the seed can be worked into soil with at least a stiff tine rake. The timing is typically between Thanksgiving and St. Patrick’s Day.
The advantage to dormant seeding is the seed is in place to germinate as soon as conditions allow, giving seedlings time to establish before summer heat arrives. The risk is the seed will germinate too early and seedlings are killed by cold temperatures.
It is also challenging to achieve good seed to soil contact with dormant seeding. While seed can be broadcast on the ground or even on top of snow with the hope that freeze thaw cycles will work to move seed into the soil, this is risky.
Core aeration with a hollow tine aerator is ideal for opening holes for seed to fall into. But core aeration cannot be done when soils are frozen, covered with snow, or too wet or dry. At this time of year, a stiff tine rake should be used prior to and after dormant seeding to help achieve some seed to soil contact.
Spring seeding of cool season turfgrass is best done in April. The advantage is reduced risk of cold temperature injury. The risk is wet spring weather would delay seeding and/or hot temperatures arrive before seedlings establish and the seedlings are killed.
If planning to overseed thin or seed bare areas in April, consider reserving a hollow tine core aerator now. When soil conditions allow in April, heavily core aerate the area and then heavily overseed with certified quality seed. Seed falls into the core holes to come in contact with soil.
For any area dormant or spring seeding, adjustments will need to be made in spring herbicide applications. Herbicides will kill turfgrass seedlings as well as weeds. If needed, the herbicides mesotrione (Tenacity) or siduron (Tupersan) can be used in the seed bed and will likely provide three to four weeks of preemergence control of crabgrass.
Postemergence herbicides, those applied for dandelions and other broadleaf weeds, will need to be delayed until well after seedlings are established. Ideally, after the new grass has been mowed two to three times. Be sure to read and follow label directions for waiting periods on new seedings.
As for a more drought tolerant grass to plant, there is no miracle grass. Kentucky bluegrass (KBG) and turf-type tall fescue are still the best cool season turfgrasses for Nebraska. If you are overseeding thin or bare areas, reseed with the same type of grass that is already there. Do select improved cultivars and purchase quality seed.
KBG and tall fescue can both be lower maintenance grasses that require less irrigation. The issue is not in the grass, but in the fact that most people manage these to be high maintenance grasses that require more inputs than necessary.
Buffalograss is a very low maintenance, drought tolerant grass. Established buffalograss will easily survive on average rainfall and with once a month or less mowing. However, it is a gray green not blue green in color and has a shorter season of growth. To establish it, one would need to start from scratch which can be expensive and time consuming. However, if a person is truly interested in saving water and using less gasoline, buffalograss can be worth it.
Kelly Feehan is an extension educator-horticulture with the University of Nebraska-Lincoln, Platte County Extension office. Reach her at (402) 563-4901 or by email at firstname.lastname@example.org.