One of the most obvious manifestations of calcium deficiency in strawberry is “tip burn” of the rapidly growing new leaves in the center of the plant.  Some varieties tend to manifest this symptom more than others.  

Calcium is an important structural of component of cell walls and cell membranes in plants.  A deficiency of calcium in the plant leads to a general collapse of membrane and cell wall structure, and the resulting leakage of polyphenols concludes with necrosis in the affected areas.  Since there is broken down and dead tissue in these areas, microbial infection frequently results, but this is a secondary effect.

The scientific literature says that in strawberry, leaves containing less than 0.9 percent calcium are deficient, with a significant percentage of plants showing tip burn symptoms.   Furthermore, calcium sufficiency is said to be in the area of 1.5% of dry leaf tissue.

Calcium deficiency in plants is not necessarily a direct result of a lack of calcium in the soil and as such might not easily be addressed simply by increasing the amount of calcium fertilizer applied.  Calcium is moved from the roots to the rest of the plant via evapotranspiration by the water conducting elements of the plant, also known as the xylem.  If there is a lot of evapotranspiration, such as on a hot, dry day, calcium will be moved from the roots and up through the plant.  Conversely, lengthy spells of cool, humid (read fog) weather will not facilitate evapotranspiration and subsequently calcium movement can be restricted.  Plant organs such as the fruit and developing leaves do not transpire as much as a fully mature, expanded leaf, and therefore would tend to be the first to express calcium deficiency.