The city of Fort Collins is in north-central Colorado, just 30 miles from the Wyoming border. Our weather can hit the extremes. This summer we had stretches in the high 90s, with very low rainfall. Winter temperatures can drop below zero, and when there’s no snow cover, winds sweeping across our open sports fields make desiccation a major factor. So, fall field cleanup must not only achieve our current goals, but also look ahead to winterization strategies for the best possible conditions for the following spring.

This close-up view shows the aeration core distribution across the turf.

As sports turf crew chief, working under Parks Supervisor Mike Calhoon and Manager of Parks Bill Whirty, I coordinate the maintenance program for 40 soccer/multisport fields, one dedicated rugby field and 33 ball fields spread across 23 sites. Our parks system is split into four districts, each housing one community park and multiple neighborhood parks all incorporating some ball fields and/or turf fields. I also serve as crew chief for one of those districts, City Park, managing the multiuse park space, which includes a collegiate baseball field.

Each district has a satellite maintenance facility equipped with several groomers and four-wheel utility vehicles for infield maintenance, mowers, and small power and hand tools for general maintenance. The larger specialized equipment for field maintenance is based at my facility and transported to the various sites as needed. This includes the Toro Pro sprayer, VertiDrain deep-tine aerator, Ryan walk-behind aerator and sod cutter, AERA-vator with a seeding attachment, slit seeder, 60-inch rotavator, combo plane, 6-foot drum aerator, a Dakota topdresser and a fleet of six tractors of varying sizes to operate the implements.

Our fields are a heavy clay native soil, so compaction is always an issue. We aerate as frequently as possible during the season to combat that. I rotate play among the fields, moving lacrosse to different fields to reduce the wear, and resetting the field layout and goal placement on our soccer fields to preserve goalmouths. We do have the luxury of pulling a field out of play for renovation at any point during the playing season. Still, a major part of our field renovation takes place during field cleanup and winterization.


Hand raking to remove aeration cores also helps prepare the field for overseeding and topdressing.

For over 15 years, play has only been allowed on our fields from the third week in March to the first weekend in November. Knowing when the season ends is a real benefit in planning and carrying out our field cleanup program. Only four of us are available to organize the major tasks in my area, and we could be diverted from that for snow removal, so prioritizing is essential.

We’ve developed an assessment program that covers 10 main points on each field, such as bare areas, irrigation problems and drainage issues. Each rating category is assigned a number on a scale of 1 to 5. This rating is then put onto a report card, which determines the maintenance priority for that field. I’ll assess every field by the middle of the fall season. The evaluation takes several days, but with one person doing the assessment, the rating valuations are consistent.

The fields with the greatest needs become our top priority. I’ll adjust scheduling according to seasonal use, too. Our football program starts three weeks later than soccer in the fall, with play running until our final weekend in November. The baseball/softball fields will be the first used in the spring. Armed with this information, I can order supplies and develop a comprehensive plan that allows us to accomplish the most in the shortest time.

This before photo shows a field assigned top priority for extensive cleanup based on the field assessment procedure.

Cleanup and winterization

I’ll order the sod for any necessary repairs early, with the amount and delivery schedule specified according to field needs. We may do lip, arc and worn area sod repair on the baseball infields while the other sports are winding down. Large area resodding on the multisport fields will coincide with the end of play on that field.

We schedule the aerations between mid-October and Halloween. For fields with minimal wear, we’ll only aerate and overseed targeted worn areas, such as goalmouths, tackling it in one step using the AERA-vator with the seed attachment.

We’ll deep tine the larger field areas. We have only one VertiDrain and the process is time consuming, so we can only cover four to five fields each year. We’ll crosshatch those fields, making two passes going in two different directions, setting the angles to work around the sprinkler heads. We pull the plugs and allow them to remain on the surface.

We’ll broadcast seed at the rate of 5 to 7 pounds per 1,000 square feet using a sports mix that is a 70/30 blend of bluegrasses and perennial ryegrasses. We follow that with a .25-inch topdressing of 80 percent sand and 20 percent compost. For fields in rough shape we’re a little more aggressive, increasing the seeding rate to 8 to 10 pounds and the topdressing to .5 inch.

The same field during the cleanup and winterization process.

We use fertigation in our community parks with 50 to 60 acres of irrigated area. It’s a huge time saver, eliminating granular fertilization of those large spaces. Everything covered by that park’s irrigation system is fertilized, including the athletic fields. We use 275-gallon totes, starting with Nitro 30, an 85 percent slow-release methylene urea, at the rate of 3 ounces per 1,000 square feet. It takes an average of six weeks for the tank to run out. We’ll wait a week and then set up a second tote, using 18-3-6 with 50 percent slow-release nitrogen (N). This fertigation is timed to start in mid-May and last into late August. For the final tote, we use Pro-balance 15-2-15, also with 50 percent slow-release N, which takes us through the rest of the season.

On occasion, we’ll supplement the fertigation with spot applications of fertilizer, consisting of 50 percent dehydrated poultry waste and 50 percent UFLEXX. Wetting agents are used if we see signs of drought or other turf stress.

As the budget allows, I’ll apply soil amendments on some of our fields to keep the soil structure intact and feed the microbes. I’m using two organic products: Restore Plus, which adds humates and manganese; and Companion, a root stimulator with amino acids. I mix them together and apply them every four to six weeks, directing the applications to specific fields. These products are compatible with multiple other products so I can tank mix nearly any material, such as iron or chelated calcium for our field with a recurring salt issue, saving the time of multiple applications. I rotate the amendment applications annually, selecting those fields that have issues, as well as the fields we constantly need to baby. By conditioning the soil, we also make the abundant phosphorus tied up in our soils accessible to the turf.

Part of our winterization is fertilization of all of our sports fields between the last week of October and mid-November with a granular 24-0-12 with 12 percent sulfur. We use quick-release N, at the rate of 1 pound per 1,000 square feet, following the recommendations of Dr. Tony Koski. This allows the grass plants to absorb the N during active growth to build up carbohydrates for the spring, as well as absorb the potassium for improved winter hardiness.

We keep mowing our fields at 3 inches with rotary mowers as long as the turf keeps growing. When we stop cutting, we’ll continue to irrigate any fields that are covered by fertigation until the tanks run out. At sites with late-season play, we need to keep the water going to serve the restrooms as well as irrigate the fields. We’re on weather alert at these sites, insulating certain piping along the restroom walls or putting heaters in the ceilings to prevent freezing. We’ll keep these irrigation systems going only as required to support field usage.

The same field following grow-in after completion of the cleanup and winterization process.

Collegiate baseball field

The exception to this process is our collegiate-level baseball field, home of the Colorado State University baseball team and the Fort Collins Foxes wooden bat summer league. Play on this field begins in mid-February, so the cleanup and winterization need to be geared for that early start.

We converted an existing field for collegiate play, excavating an all skinned infield and resetting the dimensions to install an 80/20 USGA sand and organic compost infield rootzone, with regulation mound, home plate and stabilized infield mix. We retained the native soil outfield, but redid the entire irrigation system with a closed system specific to that field. The sodded infield was harvested from a sand-based sod farm consisting of about 85 percent sand and a different organic content, so there have been some interface issues.

We baby this field, walking the infield to apply divot mix after each use. We aerate the infield with bayonet tines, using a Toro ProCore every three weeks, and pull and harvest cores every spring and fall. We overseed with 100 percent fast-germinating bluegrass. We topdress with USGA sand to match the soil profile. We aerate the outfield less frequently, timing it when the teams are away and dragging in those cores. We’ll do the cleanup and winterization aeration in both the infield and outfield around Halloween.

We use a liquid organic fertilizer combination of Restore Plus and Companion throughout the season at four-week intervals on the infield and less frequently on the outfield. We’ll use this same combination along with K-Builder 7-2-21 for one last application for winterization prior to the first week in November. We will supplement fertilization with granular applications as conditions dictate.

We mow with a Toro Groundsmaster 3505-D triplex rotary mower, keeping both the infield and outfield at 1.75 inches. We’ll gradually allow the turf to reach a 2-inch height and tarp the infield with a grow blanket on the first week in November. We’ll continually monitor the weather and keep the irrigation system going, hopefully into mid-November, unless we get snow cover. If needed during one of our dry winters, we’ll open up our quick coupler zone for hand watering through the cover and then winterize that zone again.

The only other field we tarp is the soccer field that has salt issues. We keep it growing as late into the season as we can and then cover the entire area, 110 feet by 60 feet. We’ll leave the tarps in place on both fields throughout the winter. We don’t treat for snow mold prior to tarping. We’ve only had gray snow mold once, two years ago when snows lingered until mid-March. It hit all the classic spots, but we dealt with it after it appeared and had minimal damage and no disruption of field use.

I’ll assess the condition of each field as we work through spring pre-play preparations, making notes on conditions that I’ll take into consideration during the evaluations for the next cleanup and winterization process.

Roger Daigle, CSFM, is City Park/sports turf crew chief for the city of Fort Collins, Colo.