Boron is crucial in cell membrane integrity, sugar movement through the plant, as well as the plants reproductive functions. Boron is one of the most commonly deficient nutrients in soil tests and tissue tests that we see throughout the season. Boron can be toxic placed on or near the seed. For this reason it is suggested to put it in row starters or sidedress applications. 10% Boron will mix well with UAN, 10-34-0, and ammonium thiosulfate.