Just be aware of the fact that this is no overnight project. This condition is very common on tomatoes and peppers. It is not the result of a disease or pest but is caused by a calcium deficiency. The condition is also common when the water content in the soil varies wildly. Blossom end rot can occur in soils that have plenty of calcium, but some times the plant itself is not all that efficient at getting it out of the soil or transporting it fast enough to meet the requirements of rapidly developing fruits.
Some varieties are more prone to the condition than others.
The paste type tomatoes are particularly susceptible. To combat this condition, try using a foliar calcium spray such a Monterey Chemical Foli-Cal. This product has soluble calcium that can be absorbed directly into the leaves or fruit. If the soil has limited calcium availability, use gypsum at the time of planting. Lime can be blended into the soil but only if the soil has been tested indicating acidity.