Snow Mold
Snow mold is a fungal disease of turf that develops mainly under long-lasting snow cover and damages greens and fairways.
Snow mold, also referred to as snow mold disease, is one of the most feared turf diseases on golf courses. The fungus thrives in cool, damp conditions, typically under a snow cover that lies on unfrozen ground for weeks. Two types are known: red snow mold, which forms reddish to brown patches, and gray snow mold with light gray, circular spots. Both can kill the turf, especially on closely mown surfaces. Greens are most at risk because of their delicate turf.
As a golfer you see the snow mold in spring once the snow is gone: circular, dead patches on the green that make the putt unpredictable. The greenkeepers then work with aeration, reseeding and topdressing to regenerate the surfaces. This can take weeks until the patches have fully grown in again. During this time many courses have special local rules in place, such as preferred lies on affected areas.
A common misconception: snow mold does not come from the snow itself but from the fungus in the soil. Snow is only the shelter under which the fungus spreads. Long snow covers without proper frost are the risk, not the snow as such. The accusation that "the course is poorly maintained" also falls short. Even optimally maintained facilities can be affected in a hard winter. Patience in spring is part of the golf year, because the regeneration of the turf cannot be accelerated.
FAQ
How do I recognize snow mold on the course?
You see it in spring after the snow melts as circular, dead patches on greens and fairways. The red variety forms reddish-brown patches, the gray one light gray, almost whitish areas. On the green these patches make the putt unpredictable because the ball skips over them or breaks off them.
Why is there often a special rule on the course with snow mold?
Because the damaged surfaces first have to regenerate and any further contact delays the healing. Many facilities therefore allow preferred lies on affected areas so that you can move your ball from the diseased spot onto healthy turf. The current rules are usually posted on the notice board or stated on the scorecard.
Is snow mold a sign of poor course maintenance?
No, the fungus sits in the soil and only needs the right shelter: a long snow cover on unfrozen, damp ground. Even optimally maintained facilities can be affected after a hard winter. Regeneration through aeration, reseeding and topdressing takes weeks and cannot be accelerated.