SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/433388
14 SportsTurf | December 2014 www.sportsturfonline.com Field Science Watering Seedlings are susceptible to desiccation, and the seedbed should not be allowed to dry. A newly seeded area will need to be irrigated two to four times daily depending on the weather. Water frequently enough to keep the top 0.5 to 1.0 inch moist, but avoid over-wa- tering and saturating the area. Once the seedlings are two inches high, gradually reduce the frequency of irrigation and water more deeply. After the turf has been mowed two or three times, deep and infrequent irrigation is most effective. MoWing Mowing will encourage the turf to fill in quickly. Mowing should begin when the first few seedlings are tall enough to mow. You may only mow 10% of the plants in the first mowing, 20-30% of the plants in the second mowing, and so on. Most wait too long to mow a newly seeded area, so mow early and often. Initially mow Kentucky bluegrass, perennial rye, and fine fescue at 1.5 inches and tall fescue at 2 inches. After the first three to four mowings, you can adjust your mower to the permanent mowing height which is 2 to 3.5 inches for Kentucky bluegrass, perennial rye, and fine fescue and 2.5 to 4 inches for tall fescue. As always, never remove more than 1/3 of the grass blade at any one mowing. Fertility New seedlings have poorly developed root systems and thus they cannot effectively absorb nutrients from the soil. Therefore, it is important to fertilize frequently after seeding to encourage establishment. Apply 0.75 to 1.0 lb N/1000 ft2 4 to 6 weeks after germination and again 8 to 10 weeks after germination. Assuming seeding in mid-August, these applications would be mid- to late September and again mid- to late October. Weed control There is little weed pressure in the fall so weed control may not be needed. Broadleaf weeds may become a problem in the fall, but these can be easily controlled with a broadleaf herbicide application in October or November, after the third or fourth mowing. Avoid using broadleaf herbicides in newly seeded areas until seedlings have been mowed at least three times. Quinclorac and carfentrazone are the only broadleaf herbicides that are safe to use on seedling turf. Annual grasses such as crabgrass can be easily controlled with preemergence herbicides applied in the spring. With dormant seedings or seedings made very late in fall where the area is not fully established by winter, avoid applying a preemergence herbicide in early spring because it may damage late-developing seedlings. In this case, consider using a postemergence crabgrass herbicide later in summer to control crabgrass. Do not use preemergence crabgrass controls (except siduron) at the same time as a spring seeding. As a general recommendation, delay use of these materials until new seedlings have been mowed four to eight times, depending on the herbicide. Check the herbicide label for exact recommendations. Siduron is the only preemergence herbicide that can be used at the time of seeding, but will only control crabgrass for only 3 or 4 weeks. Quinclorac can be used for postemergence control of summer annual grassy weeds in seedling turf with little risk to the desired seedlings. ■ Zac Reicher is now with the University of Nebraska-Lincoln's Department of Agronomy and Horticulture: Turfgrass Science; Cale Bigelow is Professor, Purdue University Department of Horticulture and Landscape Architecture; Aaron Patton is Associate Professor of Agronomy and Extension Specialist, Purdue University Department of Horticulture and Landscape Architecture; and Tom Voigt is Associate Professor and Turfgrass Extension Specialist, University of Illinois Department of Natural Resources and Environmental Sciences. See the Seed Calculator at www.turf.purdue.edu Avoid using broadleaf herbicides in newly seeded areas until seedlings have been mowed at least three times.