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/621615
16 SportsTurf | January 2016 www.sportsturfonline.com FIELD SCIENCE Park says grade soil when wet, and that lime, organic mat- ter, and nutrients should be incorporated via tillage prior to seeding. "Tilled soils should be firm at the surface but just loose enough to allow good seed-to-soil contact. When overseeding into existing turf (including very poor/thin turf cover) core cultivate and reincorporate cores to create a seed- bed at the surface." Pamela Sherratt, sports turf specialist at Ohio State University, says slit seeding is ideal. "Disturbing soils in the spring by tilling creates a nightmare with weeds, so it should be avoided." A blanket recommendation is difficult for when to water. Too much or too little will delay or sometimes destroy a new seeding. Insure proper moisture by monitoring soil condi- tions. "Most people do not keep the seedbed wet enough during the first few weeks," says Fowler. "If they can, I want the soil surface to be continually damp for the first 2 weeks. After that, reduce frequency of irrigation but increase inten- sity. Start off with a little often and end with lots infrequently. The trick it how you get from a to b." The first mowing of newly germinated seed should be done with care. Says Jakubowski, "The seedlings will be at a tender stage and severe scalping should be avoided. If the grass is to be maintained at 2 inches, let the grasses reach a 3-inch height, then mow." If possible, avoid sharp turns on the newly grown grass and make sure the soil is not too moist, because wheel and foot traffic can create a compacted surface area. This can make it difficult for younger grasses to break through the surface. For shorter mowing heights, 1 inch for example, the first cutting could be at 2 inches then gradually reduced after each subsequent cutting. Fowler believes that "under normal conditions" a new seed- ing should be mowed following the "one-third rule," i.e., never remove more than one-third of the plant tissue in a single mow- ing. Allowing the new seedlings to grow to 3-4 inches before the first mowing won't hurt as long as the rule is followed. Desired final height can be achieved after the plants have had some time to mature. "I find most people wait too long. I'd suggest mow- ing as soon as the leaf blades reach the mower, even if they aren't removing much plant tissue. Mowing signals the plant to start tillering and the new seeding will fill in much quicker." Sherratt says to apply starter fertilizer with seed then again 3-4 weeks after, based on soil test results. "Only a couple of pre-emergents will be useful at time of seeding. Tenacity and siduron are both pretty good." Post-emergent herbicides could be used after about the third mowing. If weed pressures aren't too severe, holding off until the fifth or sixth mowing would help reduce any potential setbacks caused by herbicide applications. Fertilizer should contain phosphorus to speed up the ger- mination and establishment. A typical starter fertilizer with a 1-2-1 ratio is best at 1 pound phosphorus pentoxide per 1,000 square feet. Do not use a pre-emergent herbicide with the fertilizer, as doing so will impede germination of new seeds. Also, if weed pressure is a concern during grow-in, follow the herbicide label for proper timing. Jakubowski says a starter fertilizer, such as a 12-25-10 with water soluble sources of nitrogen applied at 5-7 pounds of product per 1,000 square feet will be an effective nutrient source. "If a soil test revealed a deficiency in phosphorus, an application of a product like 18-46-0 would be useful. Subsequent fertilizer applications of water soluble sources of nitrogen applied at a rate of 0.25 to 0.5 pounds of nitrogen per 1,000 square feet every 2 weeks for the first couple of months would be recommended to ensure effective growth and fill-in. "Avoid using common pre-emergent herbicides like pendimethaline or prodiamine before the seeding pro- cess, as chemistries like these will prevent your grass seed as well as your target summer annuals. On areas with grass cover, the active ingredient siduron can be applied before seedling application. On bare ground, mesotrione can be applied before seeding as an effective tool to help prevent summer annuals as soils warm. Be sure to follow the labeled instructions for any of these herbicides during establishment." Rolling to level and press seed into soil. Seeding and topdressing.