Creative techniques for seeding in the fall to insure a durable field all year round.
The fall season is the most ideal time for cool season field cultivation and overseeding. Consistent rainfall and cool night temperatures help existing cool season grasses recover quickly, while higher soil temperatures created from the summer heat make an ideal time to get quick germination and growth on seed.
However, fall is also one of the most high traffic times of the year on many cool season fields. To avoid having to close fields completely, grass field managers are challenged to be creative and pro-active on fall field maintenance practices to meet the demands. Let’s re-examine some cultivation and overseeding approaches.
Fall is a wonderful time for cool season turfgrass to recover from summer stress and grow roots for fall and winter play. But black layer from constant watering, thatch from clipping and/or stressed or dying turfgrass and compacted soils from limited cultivation during summer limit what existing grass and new seed can do. Before overseeding and fertilization are considered in a fall maintenance program, cultivation should be Step #1.
De-compaction aeration: Soften the soil deep
Examples of Solutions:
- Deep tine aerator
- Soil wave aerator (ex. Imants Shockwave, Redexium VertiQuake)
- Soil air refresher (ex. Koro Recycling Dresser)
- Air2G2 blasting high pressure air
De-compaction aeration is softening the soil down below a 4” depth. De-compaction machines break up layering and hard soil. De-compaction allows for deeper rooting of existing turfgrass. It also allows better irrigation and rainfall infiltration and softens the entire field surface for safety and playability. Longer tines on a rapid tine type aerator do not de-compacted the soil. Use specific de-compaction equipment to reap the benefits.
Timing: De-compaction aeration should take place a minimum of 3x during the fall season (or as much as budget allows). A deep tine, soil wave machine or Air2G2 can be run the same day as a field event. Even if the field is under high traffic de-compaction aeration can take place. Soil air refreshing deep for de-compaction requires a 7- 10 day break and also can take place at the end of the fall season.
Surface aeration: Open up the surface
Examples of Solutions:
- Rapid tine aeration (Coring tines/ solid tines/ needle tines/ knife tines)
- Linear slicing (blades or solid slicing rollers)
- Soil refreshing aeration (KORO Recycling dresser)
Surface aeration has multiple positives in the fall. Surface aeration is any type of aeration that vents the surface (top 3-4”) for air, water infiltration and to soften the field for player safety. Using hollow tines to core aerate removes organic matter build up and/or sod layer and creates channels for air and topdressing (if it fits into the budget). Core aeration is labor intensive with the clean up of plugs, but the benefit outweighs challenge. Core aeration and solid tine aeration equally create holes for seed to fall into for seed to soil contact when overseeding. The more holes, the better! Slicing can open more surface area than most tine aeration methods to open the surface of the field as well and promote healthy plant growth.
Timing: The type of surface aeration used is to be dictated by the schedule of use. Core aeration could require a break of up to 5-7 days depending on a sand soil. On native soil, coring, solid tine aeration and/or slicing can take place with play on the field immediately after. Sand could need a 3-5 day break in order for the surface to become stable again before play. Soil air refreshing down to a 4” depth requires a 5-7 break to grow in the slices.
Examples of Solutions:
- Wide range of sizes and types of verticutting machines available
Verticutting is extremely effective in the fall, especially in conjunction with overseeding. Verticutting removes some thatch build up, opens up the black layer that can build during summer with heavy watering and will promoted Kentucky bluegrass density and durability. Like core aeration, the clean up from verticutting can be labor intensive. But just as with core aeration, the benefit outweighs the challenge.
Timing: Verticutting can take place w/ a 3-5 day break and in no effects stability or playability of a field. For practice a field could be verticut the same day as play.
Universe fraze mowing
Examples of Solutions:
- Universe Fraze Mowing (KORO Field Topmaker w/ Universe® rotor
The new cultivation technique of Universe fraze mowing has now proven to be a valuable practice. This is especially true in the fall on Kentucky bluegrass in combination with overseeding. Similar to verticutting, Universe fraze mowing promotes Kentucky bluegrass density and durability while removing thatch and organic buildups. But instead of removing 11-15% of material like verticutting, Universe fraze mowing removes up to 100% of the material to the desired depth. That depth is set above the growing point of the Kentucky bluegrass to allow re-generation. Universe fraze mowing also removes poa annua plants that are short rooted from summer stress, the poa annua seed bank on top of the field, and other weed seed that has accumulated. Universe fraze mowing also helps smooth the field surface.
Timing: The depth or aggressiveness of Universe fraze mowing varies depending on the window of time the field is off. A light Universe fraze mow cleans the very top of a field and can take place in a window of 10-14 days. Going more aggressive to remove more organic and poa annua can require up to 21-35 days, depending on the age of the field and the amount of prior maintenance.
Once fall cultivation is addressed/planned overseeding should be addressed. Overseeding in conjunction with the cultivation can added effectiveness to both practices. When preparing to overseed consider a few different things:
New genetics in fescue, Kentucky bluegrass and ryegrass are changing what is possible for fields and overseeding. Fast germination, increased aggressiveness for spreading and filling in, stronger roots for establishment and quicker playability all exist. Also lowering demands for dark green color is being replaced with an appreciation for aggressiveness and durability unlike ever before. All lead to a new world for seeding. For an example, consult SportsTurf.com online (http://read.dmtmag.com/i/318924-june-2014/19) and read the June 2014 article by Ms. Julie Adamski about a Kentucky bluegrass field that went from seed to play in 35 days. That feat has provided an example and confidence for grass field managers exploring using new seed varieties.
Additionally, the genetic improvements now make fescue and ryegrass capable of existing on high traffic fields together, in with Kentucky bluegrass, or even on their own. No longer do grass field managers have to hold their breath during disease stress times with these varieties. Do your homework on what is available from the seed companies you have existing relationships with, but consider possibly branching outside those relationships as well to find what is working for others. Keep in mind with seed; the old proverb “you get what you pay for” is 100% true.
Seed to Soil Contact
When seeding, no matter the variety you select, seed to soil contact is important. Soil contact ensures the seed is
not sitting in the thatch layer or laying on top of the ground where it could dry out quickly or struggle to push roots down into the soil. There are a few different options for overseeding that will help promote seed to soil contact.
- Seeding in conjunction with cultivation: Seeding following core aeration, solid tine aeration, verticutting, or Universe fraze mowing can promote seed to soil contact. Aeration holes give the seed cavities to fall into the soil. This is effective especially for fields still in play during seeding as the crown of the plant grows below the surface where it is protected from cleats. Do not aerate too deep though if doing so to promote seed. Verticutting cleans some thatch out and creates linear channels for seed. Universe fraze mowing cleans the thatch completely from the top, but it still needs an additional cultivation to work the seed into the soil. Keep in mind that when seeding in conjunction with cultivation, the more surface area that is opened up, the better success seeding will have.
- Using a penetrating seeder: Several different seed application machines are available on the market. With a seeder, just as when cultivating for seed, the more surface area that is penetrated the better off the seed application will be.
- Seeding before heavy traffic: Our forefathers in grass field management have handed down this method through years of use. Applying seed to the high traffic areas of a field 1-2 days before a heavy use will allow play to create the seed to soil contact. An example would be seeding the center of a football field prior to play. Keep in mind that if using any clean up techniques following the heavy traffic, it could also pick up the seed. Follow the high traffic event with a deep irrigation cycle to settle in the seed to ensure success with this technique.
- Topdressing to cover seed: Topdressing with sand, compost, or even lightly with the field’s native soil will create seed to soil contact. Keep in mind that too much topdressing burying the seed can be a bad thing.
These are just a few ideas to help solve the complex challenge of fall cultivation and overseeding. Yes, there are many, many other ideas for meeting the challenge. Make sure to ask questions of your fellow grass field managers to create more possibilities to meet the challenge. Follow sports field managers around the world on social media to witness the creativity that others are using. Share your experiences equally for others to learn from your lessons to help build creativity and idea generation.
Consider the ideas above and how they can be implemented in these two challenging situations:
Case Study #1: In-season, high traffic football and soccer field on native soil with Kentucky bluegrass and fescue
This field manager has the ultimate challenge in order to get new seed established during the busy season of the year. This field will experience high traffic through the fall even through the time it goes dormant. If you were that manager, what would you do? Take 5 minutes to create a solution and share it with your colleagues on twitter to @BarenbrugUSA and @JeradRMinnick, hash tag #fallseeding. I will share some solutions via GrowingGreenGrass.Net to @BarenbrugUSA and @JeradRMinnick on Thursday September 3RD.
Case Study #2: End-of-season, high traffic in early spring through late summer baseball field on a sand soil with Kentucky bluegrass and ryegrass
This field manager may feel relief for the end of the season, but fall overseeding will be the catalyst for the field’s survival through a busy spring and summer. This field will be exposed to high traffic even before the grass breaks dormancy in the spring. If you were that manager, what would you do? Take 5 minutes to create a solution and share it with your colleagues on twitter to @BarenbrugUSA and @JeradRMinnick, hashtag #fallseeding. I will share some solutions via GrowingGreenGrass.Net to @BarenbrugUSA and @JeradRMinnick on Thursday September 3RD.
Jerad Minnick is an international natural grass advisor and educator. Follow him on Twitter at @JeradRMinnick and find more ideas at GrowingGreenGrass.Net.