The Lone Cuke

So I have a small pot garden in the backyard.  I planted tomatoes, green beans and cucumbers.  The tomatoes and green beans grew just fine.  The cucumber, on the other hand, is a strange story.  The plant has grown like crazy....all over the place....up and down the fence.  But every day I look and there are no cucumbers.  Until today!  Finally, one cucumber.  Just one!  Look at this plant!  Why are there not tons of cucumbers on this plant?!  Any gardeners out there want to give me any advice?  Mistie, I know you're a gardener...what did I do wrong?  The only thing I can think of is that I put too many plants in one pot.  I should have only put in one plant, but the box came with like 4 and I didn't want to plant them all in separate pots.  Call me lazy. :)  Oh well, I guess we will enjoy this one cucumber.  It better taste super good!!!