Hi- it is not necessary to apply calcium or any other nutrient every two weeks around tomato plants. Most Maryland soils have adequate calcium levels. But to reduce the risk of blossom-end rot, we recommend mixing 1/8 cup to 1/4 cup of gypsum (calcium sulfate) into the soil of each planting hole and watering plants regularly when rainfall is lacking. The calcium in gypsum is relatively fast-acting and won't raise or lower soil pH. You could apply the gypsum to the soil around your plants now.  We don't recommend using antacid tablets or milk of magnesia to fertilize plants.

We suggest that you have your soil tested sometime in the fall to get baseline information on soil pH, nutrient, and organic matter levels. 
Soil testing information
Vegetable fertilizing information
Jon