While most calcium is found in the leaves, petioles, crown and roots, the small amount that does get into the fruit is critical in terms of berry structure and shelf life.
Although the inner fruit and distal parts of the fruit contain little calcium, the relatively high concentrations found in the fruit margins are particularly important in terms of fruit quality.
Trials show that calcium increases fruit firmness and prolongs keeping quality.
However, excessive rates of calcium at the expense of other cations can reduce fruit firmness and shelf life. For this reason it is important to keep calcium applications in balance with other cations such as potassium and magnesium.
Calcium also helps to reduce levels of mold on fruit post-harvest. This calcium can also be applied pre-harvest as a foliar application.
Ca reduces albinism, maintaining fruit coloration through increasing anthocyanin levels during maturity.
Silicon also has an effect on fruit quality, through improving firmness and there are indications that can also improve disease tolerance. Applications of silicon can improve shelf life. The key benefit of silicon in this respect is its role in reinforcing the cell wall.