If you have had as much rain as we have, the yellowing and blooms falling off is probably due to too much water.

I had cucumbers that didn't look any better than the day I planted them about a month ago. I finally mulched heavily to try to block out some moisture and they are looking better - growing and blooming. Plus, here in the central part of Alabama, we haven't had real warm nights until recently and I think that has something to do with "growth".

Good luck. If they don't grow, there is always the Farmer's Market!
Mimi