Samples of alfalfa (Grimm variety) were obtained from 7 Michigan soil types at 4 stages of growth for the 1st crop and at 3 stages for the 2nd. Samples were analyzed for Ca and Mg in tissue and expressed juice of leaves and stems, for moisture content of tissue, and specific gravity of juice. Variations in these characteristics were determined for alfalfa from one soil type at different hours of the day. At one stage of growth the proportion of stems and leaves on the different soil types was ascertained. In addition the amounts of Ca and Mg incorporated in the woody tissue as distinguished from those in the plant sap were determined by a special formula. Soil type influenced very noticeably the Ca content, sandy loam soils giving the largest, and light sandy soils giving the least, amounts in the plants; soil texture bore no uniform relationship to the Mg content. The concentration of Ca increased in the tissue and expressed juice of 1st and 2nd growth plants as the season advanced, but the increase was much slower in the 2nd crop, indicating perhaps that the plants were obtaining Ca with greater difficulty. Mg increased with age in the 1st crop, but decreased in the 2nd crop. Soil type influenced the amounts of Ca and Mg in the woody tissue of the plants and also the specific gravity of the expressed juice; Ca and Mg were important cations in determining sp.gr. The characteristics studied varied noticeably at different hours of the day, being usually least constant between 8 and 12.