What is the best source of calcium for plants?

Online Answer
GypsumGypsum: Gypsum is one of the best sources of calcium to plants and the safest option simply because it will not alter the soil ph levels. Chemically its calcium sulfate dehydrate. Its also called Lime sulfate. Gypsum is also used in clayey soils to remove soil compaction and improve soil drainage.
Related Questions 📌
Most farmers and gardeners resort to using gypsum to salvage Alkali soils. ... However, applying too much gypsum in the soil may also mean eliminating essential nutrients from the soils such as aluminum, iron, and manganese. Removal of these nutrients may lead to poor plant growth..