My tomato plants look good but no blossoms or tomatoes, My cukumbers look good with lots of bloosoms but no cukes, What is up?

Cukes tend to produce quicker then tomatoes, that could be the issue. As far as the flowers but no cukes, could be lack of pollinators. Have you tried to do some by hand?

Many tomato varieties need cool nights in order to set fruit. Depending on where you live that may be the problem.

There are sprays you can get at some nurseries that will help that problem