By Pam Sherratt
The official date for turf renovation in the Midwest is August 15th to September 15th. These dates offer the best opportunity for timely rains, warm soils, little weed competition and enough time for the new grass to get established before the first frost.
On athletic fields, there are several heavily-worn areas that will need constant over-seeding between now and the end of the playing season. Those areas include soccer goal mouths, sidelines, entry and exits points and between the hash marks on American football fields.
The “quickest” grass is perennial ryegrass (Lolium perenne), which can germinate in 3 days and provide ground cover in as little as four weeks. Perennial ryegrass should be applied each week to worn areas at a rate of 8-10 lbs per 1,000 sq.ft. (40-50 g/M2). During hot and humid weather, the seed can be coated in a fungicide (apron-treated) to prevent diseases like pythium, but with night-time temperatures in the low to mid 60’s (16-18C) right now, seedling disease may not be an issue.
Kentucky bluegrass (Poa pratensis) and tall fescue (Festuca arundinacea) take about 7-10 days to germinate and are much slower at providing ground cover. Their establishment speed can be enhanced somewhat by pre-germinating the seed by soaking it in water for 48-72 hours. A standard seed rate for K. bluegrass is 2-3 lbs. per 1,000 sq.ft (10-15 g/M2), with tall fescue seeded at the same rate as perennial ryegrass.
On heavily-traffiked areas it is best to broadcast seed by hand or spreader, as slit-seeders will cause mechanical damage to the playing surface. Seed can be applied prior to each game, with the expectation that the athlete’s cleats will press the seed into the soil surface. All other areas of the field that are not as heavily worn will benefit from slit-seeding, whereby the seed is placed into the soil giving good seed”soil contact.
All newly renovated areas can be encouraged and nursed along by:
- Applications of starter fertilizer applied at seeding and every 2 weeks thereafter at 0.5 lbs nitrogen per 1,000 sq.ft.
- Timely syringing, to keep seed moist until it has germinated, and then irrigation to maintain growth and recovery.
- The use of growth blankets in high-wear areas. The growth blankets are particularly useful once temperatures start to fall.
- Keeping traffic off the renovating areas, if possible.
- Using artificial light racks.
If grass cover is completely lost and the goals cannot be relocated or the field cannot be rotated, the bare soil in that area should be lightly rolled prior to games to provide stability. A topdressing of sand can also help to keep quagmire conditions from developing. An ideal solution would be to thick-cut sod those areas so that athletes continue to have ground cover to play on for the remainder of the playing season.