This is the worst year I have ever seen for cucumbers.
You can simply compare the two photos below, between my cucumbers on June 19th 2018 and June 19th 2020 to see how bad this year is.
This is how my cucumber plants looked on June 19th, 2018:
And this is how my cucumber plants look on June 19th, 2020:
What the heck happened?
We had a very cold dry May (rumored to be the coldest, driest in record). And that cold weather continued into June. Cucumbers like warm weather, and they never got it. And some cucumber plants could not take it all, and simply died.
So…. I may not have many cucumbers this year.
To mitigate, I have been planting tomatoes where the cucumbers died. In fact, my tomatoes are doing so well this year, I have been able to cut off large stalks and got them to root well enough for transplanting, they should give a good tomato harvest themselves this year despite the delay in their planting.