Tip burn on young leaves of celery, lettuce and cabbage. Death of terminal buds and root tips. Abnormal dark green appearance of leaves. Premature shedding of blossoms and buds. Because it is dissolved in the soil solution, gypsum readily migrates into the lower depths in the soil.
Most western soils contain abundant calcium, but as very insoluble calcium carbonate.
Where pH is 7 or more, the limestone is insoluble and the calcium it contains is not available to plant roots. Again, the calcium in applied gypsum is immediately available. The other component of gypsum, sulfate, supplies plants with sulfur, which is essential to protein synthesis. Sulfur is a constituent of the amino acids cystine, methionine and cysteine. It is also essential for nodule formation on legume roots, and for the characteristic odors of plants such as garlic and onions.