Ice Accumulation Danger

In Chicago, there has been ice cover on areas of turf for a couple of weeks which is causing concern for superintendents. One of the main reasons for concern is that ice accumulation on turf grass for prolonged periods can lead to terminal levels of carbon dioxide.

The ice cover creates an impermeable barrier, eventually trapping high levels of carbon dioxide from exiting the turf canopy. Simultaneously, this decreases the levels of oxygen for the plant.  If ice coverage is prolonged (30+ days), the buildup of carbon dioxide becomes too great for some plants to survive, specifically poa annua.

How can ice accumulation and lethal levels of carbon dioxide be prevented? Avoiding prolonged, non-porous buildup of ice sheeting is a good start. Non-porous, clear ice acts as a magnifying glass. Therefore, the turf will start respiring and building up gases beneath the impermeable sheet. Porous ice is cloudy, which helps prevent the infiltration of sunlight.  No sunlight means reduced gas buildup. If you are dealing with non-porous sheets of ice, you may need to remove them. The best way to remove ice without damaging turf is by melting it. There are multiple materials you can choose to aid in melting ice:  black sand, dark, organic fertilizers and even sunflower seeds. If the ice is more porous, gases are still able to be exchanged, leading to a significantly reduced chance of turf damage. If turf damage is experienced after the ice has finally melted, aggressive tactics will likely be needed in order to speed up recovery, especially on greens. Some tactics include increasing fertility, high amounts of over-seeding, and increasing the canopy/soil temperature to promote germination and growth. Environmental conditions often make it impossible to start seed in early Spring, in which case sodding may be the only option.