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Fall Seeding Tips: Maximizing Your Turfgrass Investments

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From the home lawn to the biggest events under the brightest lights, getting grass seed to grow can seem frustratingly simple to unnecessarily complicated. From time to time, we interact with customers who experience turfgrass seed failure or simply do not see firsthand the experience they had hoped. We understand the frustration of our customers who do all the preparation required to repair a damaged turfgrass stand or establish a new lawn from seed, only to fall short of expected results. While there are many instances when mother nature or business structures don’t allow for the highest potential of seeding success, we hope we can provide some assistance and boil down the core factors for successfully establishing a beautiful, functional turfgrass stand. Whether utilized hands-on by turfgrass managers, to be used to aide in turfgrass business decision making, or even as a brief early-morning read gazing upon a field of lush, dew-laden grass blades with coffee in hand, we at Barenbrug USA hope these suggestions will help our end-users, who have already invested in our grass seed, get the most out of the grass seed they’re working hard to invest in.

Plant/Product Selection

Proper seed selection must be put first and foremost in turfgrass renovations and new seedings – even more so for turf areas that command a higher value once established. Utilizing the best genetics possible for establishment, durability, and recovery should be essential in the decision-making process, especially for a high trafficked turfgrass stand. Other turfgrass needs might require the best drought tolerance, shade tolerance, or disease resistance. Regional environments and the function the turfgrass will be serving will be the dominant plant selection criteria by species blends or mixtures. Microclimates, and more importantly, the customer’s individual needs, will guide plant/product selection closer to the end of the process.

While the cost of seed is always at the forefront of purchasing decisions, keep in mind the role of seeding rates among differing turfgrass species. While some species like Perennial ryegrass are often the quick go-to options due to their less expensive nature, it might cost more compared to a Kentucky bluegrass product that has one-third of the seeding rate. In this situation, the bluegrass might be on the same playing field if it is less than 3x the cost of the ryegrass. Keep in mind this does not consider traits like disease resistance or other factors that might sway into the favor of either turfgrass by providing added value, depending on the region of use. There can even be varietal differences between species in terms of added value that can sway plant selection.

Plant breeding is focused on the core needs of high use turfgrass areas. Quick establishment and aggressive growth are a few with the biggest focus. Other vital needs tend to be drought tolerance and disease resistance, and even for other low maintenance areas. For high performing turfgrass areas, aggressive growth to push stronger, deeper roots leads to quicker access to a greater area of nutrients and water, leading to enhanced establishment and general turfgrass performance. Overall, many new varieties are achieving excellent disease resistance in some significant areas, with many turfgrass breeders aiming for similar qualities. However, some varieties will still show differing characteristics that make them unique in the marketplace.

At Barenbrug USA, Barvette HGT probably the most fitting of that description. HGT is unique in that it is resistant to many diseases, is extraordinarily aggressive and traffic tolerant, and somehow also produces minimal amounts of thatch. With all the money-saving features of this plant, it does have a lighter color doesn’t necessarily hit the highest overall performance in national tests like the National Turfgrass Evaluation Program (NTEP) when compared to other elite bluegrasses like ‘Barserati.’ Taking note of your turfgrass needs and looking out for traits that can potentially reduce your overall maintenance budget will help in the decision-making process. Barenbrug Technical Experts or your local ATS Representatives are always able and willing to assist in narrowing down top performing options for catering to multiple needs in the turfgrass industries.

Seeding Window & Germination

While cool-season turfgrasses can be established in Spring and fall, fall is generally the ideal time to seed. In the Spring, cooler soil temperatures (below 50 degrees) will slow the germination and establishment process. Remember, soil warms up much slower than air temperatures! Also note that air temperatures over 85 degrees will be detrimental to germination and seedling survival, especially on cool-season grasses. It is often a good idea to aim for early to mid-September. At this point in the year, soil surface temperatures are still near peak levels from the summer heat and high sun angle, encouraging quick seed germination.

Meanwhile, cooler night temperatures reduce the heat stress on emerging seedlings and help them get a break from potentially stressful heat waves that sometimes cannot be predicted. Unfortunately, September can be one of the most high-use times of the year for sports fields, golf courses, and other outdoor recreational areas, which will then lead to opting to perform more invasive maintenance projects later in the year. Fields and golf courses often remain open daily, so creative practices are required to meet demand and improve overall turf quality.

When aiming for the ideal seeding window, there are no guarantees from one year to the next. Some years it seems like summer never comes in some parts of the U.S., and in others, Spring and Fall might become non-existent. In cool-humid areas like in Western Oregon and Washington, where much of the world’s grass seed is produced, heavy fall rains may come in October and prevent any heavy equipment mowing until the following Spring on softer clay soils. Always keep an eye on the extended forecasts surrounding your desired seeding window and note any existing conditions that may delay seeding further like herbicide applications, extreme rainfall events, or even elevated temperatures with very little precipitation. Using coated seed will improve the chance of seeding success in non-ideal conditions, which can be utilized as a strategy. However, extreme weather may still have significant impacts on germination.

One other factor in establishing the beginning or potential end to the seeding window is the germination time of the grass species being used. Turfgrass breeding aims at reducing the required time to germinate seed within each species, but there is an even larger difference between each species. Germination refers to the time it takes for a seed to sprout, producing both a grass blade and small root. This period also varies with air and soil temperature, moisture, and soil type. Under ideal conditions, ryegrass will typically appear within 5-10 days, tall and fine fescue within 8-14 days, and bluegrass around 21 days. It will take a few more weeks past germination to fill into greater degrees, and more aggressive types can fill out in that amount of time. HGT has even been seen to return to full play after sports field renovations including fraze mowing and reseeding. Using more aggressive types of grasses is advantageous to high-end facilities by being able to return to business at a much quicker rate.

Site Preparation

Whether seeding or sodding, successful establishment is closely tied to site preparation prior to seeding or lawn installation. Taking shortcuts during soil prep will often come back to haunt the user in the form of chronic turf problems, such as compaction, uneven surfaces, poor uniformity of water retention, water runoff, weeds, disease, and the dreaded case of poor germination. These will all require added inputs and time to get growth back on track or to previous levels of quality.

Eliminating weed problems existing on the site is an essential first step. Even when weeds are not visually present, virtually all soils contain dormant weed seeds that, when exposed to sunlight, moisture, and warming soil temps, will quickly germinate. Whenever soil is disturbed, tilled, loosened, or raked to plant, these dormant weed seeds are exposed to the mentioned ideal growing conditions. Most weeds present in a new turfgrass area are from existing soils, newly added topsoil, or brought in by wind, equipment, or other means. It is recommended that once the seedbed is prepared (see next paragraph), the area be irrigated to purposefully germinate existing weed seeds, prior to seeding of the desired turfgrass. Once germinated, these newly sprouted weeds can be quickly and easily controlled. Once controlled, lightly loosen the top half-inch of soil for planting grass seed. DO NOT use a pre-emergent weed control prior to planting, as this may undoubtedly cause damage or failure of your grass seed to germinate.

Soil testing is also suggested before establishment. Check with your local Cooperative Extension Office on sampling techniques and where your local soil lab is located. Soil testing provides vital information such as soil pH, the availability of nutrients including nitrogen (N), phosphorus (P) and potassium (K), micronutrients, salinity, etc. Be sure to request soil improvement recommendations along with the results. Soil pH levels are very important, with pH best between 6 and the low 7’s. To lower the pH and make the soil more acidic, add elemental sulfur. To raise soil pH and make more alkaline, add lime. Use these materials only when a soil test indicates a need and apply the recommended amount. Incorporate these materials into the existing soil, approximately 3-4” deep. 4-6” inches or more of well-prepared soil is suggested.

When preparing the soil, it is essential to establish a favorable final grade. Rough grading should include removal of any sizeable rocks or other debris, such as construction debris. Eliminate low spots or raised areas. Final slopes should be 1-2% away from buildings (one to two feet drop per 100 feet of run) to assure good surface drainage. At sidewalk/patio edges, the grade should be approximately 1” below hard surface.

In other situations, plant debris from excess stem growth and outside sources can accumulate on the surface to create thatch and organic build-up. This accumulation hurts playability among other critical agronomic concerns such as increased fungal incidence, habitat for pests, and decreased water percolation. Thatch removal before overseeding is an excellent time to clean this accumulation in preparation for incoming seed. It typically doesn’t need to be fully renovated or incorporated into the subsoil profile, but rather a removal of the accumulated material. This will create a seed bed and support quick re-establishment. Examples of organic management techniques may include verticutting, spring tine harrowing, brushing, and fraze mowing.

Seeding Prepared Areas and General Concepts

When it comes time to broadcast seed on the bed of lightly loosened soil, there are a few things to keep in mind. First, you’ll want to know the seeding rate you’re aiming for. To hit that number accurately, you’ll want to calibrate your spreader of choice, and with years of experience, you already know what you want to hit. As new varieties are bred, they have the chance to vary in seed size, inherently altering seeding rates by very small margins. In some cases, some varieties end up being sizably different than the others within a species. In Turf Blue HGT, a component mixture of over 30% Barvette HGT by weight takes up almost 50% of the bag by seed count due to its lower seed size and increased seed count. In the overall blend of Turf Blue HGT, these differences aren’t substantial enough to alter the seeding rates. Further trialing is being done to assess whether this unique trait of HGT can translate into lower seeding rates with similar establishment performance, which may ultimately save our end users more money.

Another concern regarding seeding rates involves using pure live seed (PLS) as the standard for the ideal rate. PLS is calculated simply by multiplying the seed’s germination percentage and total purity, which is located on the seed tag, typically on the lower side of the front or bag of the seed bag. With a purity of 98% and germination rating of 85%, you’d be looking at a PLS of 83.3%. As you can see, the PLS score is identical to the germination rating since the purity is so high. When purity drops, you lose PLS to inert matter, other crop seed, or even other weed seeds. From there, you will divide 100 by the PLS score (100/83.3) to get 1.2 pounds of seed per 1 pound of recommended seeding rate. At 2-3 pounds required per thousand square feet for Kentucky bluegrass, you’d be looking to put out between 2.4-3.6 pounds per thousand.

One of the last steps before getting to watch grass grow involves putting the seed out and ensuring good seed to soil contact. For more uniform seeding patterns, split the seeding rate in half and make two passes in different directions. In the name of uniformity, Barenbrug’s Yellow Jacket seed enhancement is colored bright yellow for easily visible skips, or the affirmation that you have no skips because skips are annoying. Areas being seeded from bare soil can simply be seeded evenly by your preferred method (broadcast, drop, etc.) and gently incorporated into the loose soil no more than 0.25” to 0.5” depending on the species. Making sure the seed is buried will protect your investment from unfortunate events such as heavy rain, wind, super-strong ants, and birds that seem never to get full. Once applied and incorporated, move your focus on to irrigation practices, and plan for a follow-up fertilizer roughly one month later, amounts and frequencies depending on the ensuing management level.

Seeding High Use Areas

Seeding a high use area can pose challenges such as moisture regulation and damage from traffic, especially when closing and suspending play is not an option. Depending on the equipment, seeding can occur in the middle of play, but the strategy then adapts to turfgrass conversion through interseeding, rather than starting from scratch. This strategy may be difficult to see results fast. Still, aggressive varieties and well-timed seeding can speed up the transition, or simply provide a benefit throughout the high use periods by adding elements of recovery.

The premier equipment to be used for seeding into existing turfgrass is a slit seeder. This type of equipment is used across the world from golf courses to sports fields, of which regularly seed into existing stands of turfgrass to increase diversity and fill the soil seed bank with desired plant species. Seedlings germinate while buried under the soil, adding a layer of protection from traffic and other stresses that are common to occur. This is often the best option for seeding high-use areas and is typically done in multiple directions for best coverage.

Slit seeders provide the greatest seed to soil contact, but if they aren’t available, then the next best option should be whichever method can maximize soil contact above any other factor. Limited seed to soil contact will enable seeds to dry out much easier, increasing the chance of seed mortality. Many field managers spread seed with broadcast spreaders and allow the players to “cleat it in.” This strategy can work on sand-based fields, but for the majority (soil-based fields), play can cause the soil to re-compact and lock up, decreasing seed survival. The best practices accompanying broadcast seeding involve surface aeration machines to create holes for the seed to fall in to, followed by sand topdressing. When seeding in established turfgrass areas with adequate cover, it is recommended to reduce seeding rates by half.

Getting good seed-to-soil contact is critical for germination to prevent the seed from drying out. Seed coating technology has improved to aid in providing more constant moisture, fungicide, soil surfactants, and even fertilizer, all in one package. Seed coating will improve germination, but ultimately poor seed-to-soil contact can have very detrimental effects. It should also be noted that seed coating technology results in 50% of the amount of seed per pound, as the other half is devoted to coating ingredients. We don’t recommend the doubling of the seeding rate due to trials that show similar or improved establishment over six months to a year after seeding when compared to uncoated seed. Not only are more of the coated seeds further along in development as time progresses, but more seeds survive through drought and disease stress, shrinking the gap between 50% seed. Obviously, for those that are seeding in extremely low-stress environments will have more raw seeds survive than in stressful environments. Still, a strategy among coating seeds in the turfgrass and other seed industries is to pass along some of the cost savings back to the end-user, which is a common question. “Why is coated seed less expensive?”

Irrigation Tips for Seeding

One of the single most frequent reasons for seedling mortality across all turfgrass industries is related to proper irrigation and early moisture management. The very first time that water contacts grass seed, the seed takes in the moisture and begins a process within the germination cycle, called imbibition. If at any time from the first wetting of the seed the seedlings dry out, the seed will die. No amount of attention or watering will revive dead seed, and much of the hard work will have been wasted. Thus a light watering 3-4 times per day is necessary to assure maximum sprouting.

Once the seedlings are approximately 1” tall, watering should be reduced to 2-3 times per day, depending on weather conditions. As mentioned, incorporating seed into the soil will improve seed to soil contact and help retain moisture. Another option is to apply and/or incorporate products that will help conserve moisture and enhance germination, such as mulches, peat moss, and more. Whatever product you select, it must be ‘weed-free’! Once your grass is established, your turfgrass must be watered regularly, especially through hot, dry summer months.

“Drought tolerant” or “drought-resistant” grasses are more tolerant or resistant to drought, but ONLY when fully established. While the turfgrass is establishing, regular irrigation is critical, but be careful not to oversaturate the soil, or seedling diseases may take hold. If high moisture and humidity are unavoidable for long periods and can be planned for, Yellow Jacket coating can be built with a fungicide to protect against seedling diseases, further protecting the investment.

Micah Gould
Market Development Manager
Barenbrug Professional Divisions