Ohio State’s turfgrass specialist and SportsTurf magazine “Q and A” columnist Pamela Sherratt says start preparing now for the rains you know are coming next spring.
Q: How can we prepare our school fields for spring rains and avoid cancelled games?
A: You can start preparing for that now. Take some time over winter to walk the fields and identify areas with standing water or poor surface levels. Do the same with skinned areas on baseball and softball fields. Take pictures and keep records of where those areas are and set priorities at to which areas get renovated first when the weather breaks.
This pro-active approach is the first step to making sure your fields are resilient.
Resiliency is a word I’ve heard a lot recently in regard to climate change and how we must be prepared for adverse weather conditions. Climatologists are predicting that dry areas of the country will get drier and wet areas will get wetter. They are also predicting that USDA Hardiness Zone maps will move northwest as temperatures increase and we’ll be dealing with plants and pests previously only seen in southern states. In central Ohio, we have certainly seen an increase in the intensity and frequency or rain, leading to floods and saturated soils. Given that we typically get excessive rainfall in spring and fall in the northern states already, we can surmise that wet conditions are going to continue, and probably get worse. Rain events that happened every 50 years may just well be something we witness each year and we should start planning now on what that means for our industry and how we can create playing surfaces that can handle rainfall events. The answer to that of course is drainage, which must be our focus moving forward.
The most important factor in providing athletes with a durable field that drains is surface grade. In essence, fields that are not graded, or have low spots, will hold water. So while there are many ways to improve field drainage, like aeration, topdressing or drainpipe installation, I’m going to focus on surface grade because that’s what ultimately dictates where the water goes.
In regard to baseball and softball skins, skinned infields should be laser graded every 2-3 years and this should be a standard line item in the maintenance budget. The goal is to create a 0.25 to 0.5 inch slope from the pitcher’s mound to the outfield. Any less of a slope and the water won’t move, any more of a slope and the water will take soil material with it and dump it into the edges, causing lip problems. Even with great surface grades, a heavy rain before a game can cause issues on skinned areas, so here are some extra tips:
Before each game, fill in low spots—use infield mix that matches the existing soil mix, add 20% soil conditioner to it, and tamp it down to make sure it’s firm and not going to move. Before it rains, if you have tarps, cover the pitcher’s mound and home plate. If puddles do form, remove the water with cups, sponges, soaker pillows or pumps. It is also possible to create a siphon with a hosepipe. Lightly rake the wet area to create ridges in the soil. This increases the surface area and allows it to dry out faster. If you use a drying agent to soak up moisture, keep in mind that drying agents are typically finer graded than soil conditioners and should be removed from the infield after they have done their job. Never brush water off the infield, over-work the soil mix, rake too much, or ever use cat litter or corncobs as drying agents.
In regard to natural grass athletic fields, drainage can be improved by maximizing surface drainage (run-off) via a laser-graded crown. A crowned field means that the grade of the surface slopes from the center down to all four sides of the field, allowing water to run off the playing surface. The average crown on an athletic field ranges from 1% to 2%, depending on which sport is being played, with soccer and field hockey generally requiring a lower crown height. Many professional regulations do not specify or prefer a crown on soccer fields, but those guidelines are typically based on sand-engineered fields, not native soil. The National Federation of State High School Associations recommends a slope of ¼ inch per foot from the center of the field to each sideline for football fields and a minimum of 1 to 1.5% percent slope on native soil soccer fields. On soccer fields with underground drainage, they recommend the slope should be no less than 1% slope. Under no circumstances should a native soil field be flat.
In conjunction with a graded crown, interceptor drains are used to capture surface runoff that occurs due to the slope of the field. Interceptor drains are placed in areas that receive the most runoff, and as far outside of the field of play as possible to limit potential injuries. Interceptor drains give the surface water a place to go, rather than just sitting on the perimeter of the field.
Skinned infields should be laser graded every 2-3 years and native soil fields should have a crown or slope that moves water from the surface to an interceptor drain. Proper grading is the cornerstone of ensuring that fields can shed water and host games.