What is that White Stuff on the Squash Plants?

Some of you may have seen me spraying a white liquid on our squash plants in the fieldon Friday. This product is an organically certified protectorant called Surround. The primary ingredient is Kaolin clay, which is a natural material also found in many cosmetic products. Emma described Surround as sunscreen for the plants, which is a great description. It leaves a white film on the plants which has multiple, safe benefits. We primarily use it because it is a physical deterrent for insects that like to land on the plants and suck the juices from the leaves, simultaneously infecting the plants with a bacterium that causes the plants to wilt. Surround also helps keep plants stay cool by reflecting the sun. Heat stress can be a problem for young, sensitive plants, especially when we plant them in the black plastic mulch. Surround can reduce temperatures on the leaves 10-15 degrees F. Lastly, it is actually a sunscreen, protecting delicate leaves from the intensity of the sun. The film eventually washes off in the rain. While we sprayed it on plants that aren’t old enough to be producing squash, if there were squash on the plants it is safe to eat the squash on the same day as spraying, after simply rinsing them.