My cucumber plants have not produced much yet. The first of the two "Mini Munch" plants has given me three fruits so far, but the first of the "Diva" has yet to be picked. Whilst tying-in the plant I found this very anaemic-looking cucumber nestled amongst the lower leaves:
In this next photo you can see the cucumber right at the bottom, just above the rim of the container.
The four plants in the container have got quite big now, and the cucumber in question had been concealed by the big leaves, so presumably it didn't get enough light. Normally "Diva" has dark green skin.
I have removed a couple of leaves, and rearranged some others, to let some more light in, so maybe this fruit will green-up over the next couple of days? We'll see.