My tomato plants are growing and flowering but when the flowers fall, there are no little tomatoes. This has been a common question all month, and there is a reason that tomatoes are not bearing normally this spring.
Tomatoes are very sensitive to night temperatures.
They will flower, but will not begin to pollinate and set fruit until nights approach the high 60s. We have experiences many nights during April where temperatures dropped into the 40s and 50s. Even though this is not cold enough to seriously harm the stems and leaves, such temperatures result in tiny aborted fruit. On a more positive note, plants have had time to become strong and develop a larger size. This might allow them to set and mature heavier than normal crops later.