CalCarb is a readily available source of calcium and carbon dioxide. Calcium is critical to the health of your plant, contributing to the strength of cell membranes and regulation of nutrient use. Calcium is known to play a major role in the quality of many crops, including peppers, tomatoes, and watermelon. It is also able to reduce the effects of heat stress in plants. CalCarb foliar booster works great in both indoor and outdoor environments.