Listed below are several homemade sprays that I have used for years. I believe that my grandfather also used these and left the recipes in one of his gardening journals Seaweed Spray Seaweed spray is rich in nutrients and minerals. It provides protection from many fungal diseases and can be used to prevent damping-off. How to make Seaweed spray: Use 2/3 cup of kelp or seaweed concentrate to 1 gallon of water, spray. You can get kelp or seaweed...