Good Morning Dawn, 

Thank you for contacting the U of M Extension Service. 

Please click on the following link from the U of M Extension Yard and Garden website about growing cucumbers: 

https://extension.umn.edu/vegetables/growing-cucumbers#disorders-3252212

This information states:

• The first blossoms often drop from the vines. This is not a problem, since the first flowers to appear on the vines are male. The female flowers, which open later, have a swelling at the base that forms the fruit, also known as the ovary. After bees pollinate these female flowers, the fruit develops.
• Poor fruit set could be due to not enough pollination. Cold, rainy, or cloudy weather can reduce pollination.

The poor fruit set is probably due to the cool and wet weather we've been having. No pollination. It appears your plant is in a pot on the deck. Maybe harder for the pollinators to find.

I would trim off the bad fruit and wait for more blooms and pollination. This should produce good fruit. 

Good Luck!