Someone recently mentioned to me that I hadn't written a good old fashioned meteorology post in a while. So, here's a fun topic for you, one that you can show off to your kids if you can catch it at the right time. I'm taking a bit of stretch here, since this topic overflows into biology, which was never my strong suit.
While many of you in the northern United States have been struggling with record snowfall and record cold temperatures this winter, along the Gulf Coast of Florida we have seen quite a bit of rain. In fact, most Nor'easters form near where I live, and in their infancy the systems will dump quite a bit of rain here.
When the excess rain saturates the ground, plant life will adapt accordingly. One of the ways some plants will adapt to the excess available moisture is through a process known as guttation. I know, a funny word, right?
Guttation occurs when a plant has turned off its transpiration processes, usually at night, so excess moisture cannot evaporate from the surface of the leaf. Instead, root pressure will cause the moisture (along with other chemicals and sugars indigenous to the plant, known as xylem) to get pushed out through the leaf edges. Because of the tapering at the top of a blade of uncut grass, a larger droplet often forms at the very tip.
Guttation is not dew. Dew is atmospheric moisture condensing on colder surfaces, and is pure water. Guttation is moisture secreted from within the plant itself, and contains xylem sap.
I have seen guttation year-round -- so long as the air temperature is above freezing -- in every state I have lived in during my adult life*. It's more likely to occur during a period of excess rains, such that soil is saturated. The large droplets on the tips of the blades occur most often on uncut grass, so that first growth in the spring before the first mowing-of-the-lawn is a good time to look for it. If you're near a wild field or meadow, that's a good place also. It happens most often at night, so you'd need to catch it close to sunrise. The moisture will evaporate quickly once the sun hits the surface.
*If you're wondering, that would be Pennsylvania, Louisiana, Ohio, North Carolina, Nebraska, and Florida.
These pictures were taken on February 8, 2013 in Navarre, Florida. I had to lie in my yard with my camera's telephoto lens on manual focus. We had heavy rain the previous day. This was the same day the northeastern U.S. started to experience the "Blizzard of 2013" (February 8-9, 2013).
