Peach, tomato, and buckwheat were grown in sand cultures with varied amts. of F, ranging from 0 to 400 ppm. Data were recorded on the amt. of F in the substrate required to produce visible injury, length of time required for each plant to show external symptoms of F injury, characteristic pattern of injury, and the relation between the amt. of F in the substrate to that in the plant. No visible injury was produced by a concn. of F less than 10 ppm. Concns. of 200 and 400 ppm. killed the plants. Concns. of 25, 50, 100 ppm. produced moderate injury. The general pattern of injury was similar on all spp. consisting of a scorching of the foliage. In actively growing plants the tips of leaves were generally affected first. Fluorine accumulation in the plant tissues increased with an increase of F in the substrate. The amount of F in the leaves was significantly greater than that in the stems. Indications are that these effects may be modified by growth status, light and moisture relationships.