As the snow melts, particularly because many areas of the Prairies have had so much snow this winter, gardeners will have to be on the lookout for snow mould. This fungal disease can attack lawns during the period when the snow is melting and cause significant damage to the turf.
Gardeners should be observant as deep snowdrifts melt, particularly those that are the deepest and thus are taking the longest to melt as well as those in the shade or where the deep snow has been compacted. These areas are most at risk of being attacked by snow mould because often along the edges of such drifts there is gradually seepage from the drifts. Snow mould will appear in the form of white, grey or pinkish cotton-like mycelium that will cover the surface of the ground. The mould thrives in moist conditions when the temperatures range from 0 C to 7 C.
There are preventive measures that can be taken in the fall to help reduce the risk of snow mould. Nitrogen fertilizer should not be applied late in the summer as this will encourage lush growth, which will encourage the development of mould. The grass should go into the winter short – no longer than seven cm– so that it will not become matted and provide perfect habitat for the mould fungus spores. Before the snow arrives, any trash on the turf should be removed by raking and it isn’t a bad idea to give the grass a bit of a rake with a leaf rake to lessen matting and improve aeration before it goes into the winter.
In the spring, careful observance is important to spy snow mould infection early so that it can be better controlled. Rake and shovel the snow from large banks that are lingering to scatter it so that the snow melts more quickly. The enemies of snow mould are air, high temperatures and sunshine. Roughing up the areas with a leaf rake will help to dry them out, allow air and sunlight to penetrate the grass and discourage the fungus from getting established.
Snow mould, unless it is a severe infestation, usually does not completely kill the grass but it does set it back and often patches of lawn will take all summer to recover, even with a fair bit of pampering. If dead patches occur, the best thing is to reseed or to cut the dead patches out and replace them with some sod. Keeping the areas well watered and fertilized will assist in the recovery process. If the same areas are subjected to attacks of snow mould every year, one solution might be to replace the grass in those areas with a hardy Kentucky bluegrass, a type of grass that seems to have a high resistance to snow mould.
– Albert Parsons writes from Minnedosa, Manitoba