This time of year it seems you wake up every morning to a lawn full of dew, or what you think is dew. Interestingly enough, much of what you are seeing is most likely guttation water. Dew forms when condensation occurs and moisture will form somewhat evenly on the leaf surface. You can see in the first picture the thin layer of moisture on the entire leaf surface from dew. Guttation water is the larger droplets of xylem sap that the plant omits from the water glands, or hydathodes near the tips of the leaves. These droplets are much larger than dew. These droplets are very obviously different from the thin layer of dew you can see on the leaf surface in the pictures below.
These pictures were taken around 6am a few days ago in my front yard. No irrigation was applied that morning as that would have washed off the guttation water.
So why do we care? Scientists have found that guttation water contains different organic and inorganic compounds, including sugars and other proteins. These compounds are a food source for disease pathogens and can therefore have an affect on the severity of disease in your lawn. All lawns have different pressures but if you have a lawn that historically has had issues with different diseases you may want to consider running a very light (several minutes per zone) irrigation period on the mornings that you had not planned on watering. We are not looking to actually give the turf any water on these days, just wash off the guttation water and spread it out so it dries faster. This watering cycle can be applied around 6am. Any golfer with an early morning tee time will generally see the grounds crew busy rolling or dragging the moisture on the greens and tee boxes. Yes, this is partly to spread out the moisture for better ball roll, but they are mainly doing this to help prevent disease on their greens and tee boxes. So, if you are fighting disease, the next time you plan to skip a watering cycle maybe instead consider a real quick cycle to rid yourself of the guttation water.
Any questions or concerns? Please email office@myturfllc.com or call us at 616-813-3135.
Jason Kregel