Get the ph of your soil tested by your county extension office. If you are acid, add whatever calcium bearing suppliment is recommended in your area. If its neutral or alkaline you may be fine on calcium. Your county extension office cań advise. Zucchini blossom end rot alerted me that I needed to supplement calcium. Bone meal is often recommended, but mineral. Or shell suppliments are cheaper or favored in some areas.
eta;oh u.k.... is there a local equivalent to the u.s. county agricultural extension service?