Calcium Carbonate Based Products Help Prevent Sun Damage to Fruits and Veggies

Aug 12, 2017

Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. Although kaolin clay makes a great sunblock for your sensitive vegetables and fruits, many farmers prefer to use a product that’s easier to wash off. Calcium carbonate, the main component of agricultural lime that raises the pH of our soils, is also the main ingredient in several products that act to protect fruits and vegetables from sun scale. Unlike kaolin, which actually blocks the sun’s rays, calcium carbonate sprays form crystals that act like tiny mirrors and reflect the sun’s rays. Kaolin sprays, which coat the leaves and fruits with a white film, reduce photosynthesis to a greater degree than calcium carbonate applications and are much harder to wash off. For farmers, the choice may come down to total costs. Kaolin sprays are cheaper but the extra post-harvest washing may make them more expensive in the long run.