Effects of a Wet Spring
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Effects of wet spring on turf
With the well-above average rainfall this spring, questions are starting to arise about the short and long term effects on lawn, golf and sports turf:
Rooting-Though no official records are kept, rooting tends to be shallow and limited on water-logged soils because of a lack of oxygen. Effects of a wet spring like this spring are compounded with heavy clay soils, compaction, and poor drainage. Adding to this is the short- and long-term stress from too infrequent mowing around rains. No visible effects are seen now, but look out for quickly drought-stressed turf if weather dries up in the near future. Since most of our root growth in cool-season grasses occurs in April and May, plants cannot "make up" for poor spring root growth with extra root growth in the summer. Thus poor rooting from wet springs will plague a turf throughout the summer requiring above average irrigation and increasing susceptibility to root-feeding grubs and root infecting diseases like summer patch.
Fertilization - excess growth and maybe some potential leaching of the applied nitrogen may force increased N rates in the May and June applications and potentially the fall applications also. Red thread or dollar spot in lawns, roughs, and sports fields are sure signs that extra nitrogen is required.
Diseases – Mushrooms growing in wet areas can be easily handled with mowing or raking. Visible diseases working now in the warm, humid weather include red thread and dollar spot that can be managed with increased nitrogen on many areas and combined with fungicides on high value areas like golf courses and athletic fields. More insidious diseases active in wet springs include take-all on younger bentgrass and summer patch on Kentucky or annual bluegrass. Since root systems are likely compromised as discussed earlier, symptoms from root-infecting diseases show up as soils dry and can persist throughout the summer. Applications of labeled DMI or QoI fungicides now on areas perennially infected with take-all or summer patch should help minimize future damage.
Insects – Wet spring probably won't affect our turf insects much, though we wouldn't notice it anyway as we're swatting at all the mosquitos.
Weeds – Preemergence herbicides do not leach and so I would not expect decreased control. The DNA herbicides (pendimethalin and prodiamine) tend to break down a little faster in anaerobic (water-logged) soils than in dry soils, but it is difficult to predict the ultimate effect of that. More importantly, quickly thinning turf as weather inevitably dries out this summer will create perfect conditions for late-germinating crabgrass, yellow nutsedge, and/or summer annuals like spurge, oxalis, etc.
Mushrooms growing in wet areas in lawns are not cause for concern and can be easily controlled with raking or mowing.
My rule of thumb is never eat anything that grows in your turf though!
Zac Reicher, Professor/Turfgrass Extension Specialist
Rick Latin, Turfgrass Pathologist