This is called blossom end rot and is caused by several problem. Too much water (heavy rains?) or too little water means inconsistent watering. Another cause is lack of calcium in the soil. Using a fertilizer like Osmocote with micro nutrients (this would include calcium) and keeping a consistent supply of water will help avoid this problem. There is plenty of time this growing season to add some fertilizer and be more careful about watering. Using a mulch on top of the soil will help as well. I think you will still have a great harvest this summer. Keep growing, Marianne Binetti