Just before applying your calcium spray towards your plants, you should definitely dilute it in water (non-chlorinated). include it into a spray bottle then apply it to the root zone. Applying it to foliage won’t automatically get the job done. It is usually caused by a lack of calcium availability https://cristianlevmg.tribunablog.com/the-2-minute-rule-for-calcium-nitrate-fertilizer-manufacturing-process-43894002