Q.Armenian cucumbers turn yellow before ripening
I planted Armenian cucumbers in my greenhouse and have tied them up to a string to grow up instead of along the ground. It has lots of blossoms and some small cucumbers forming. The plant looks healthy and is vigorous in its growth but most of the cucumbers get to be about an inch to 2 inches long and they turn yellow, shrivel and fall off. I have had some get quite long, about 6 ot 7 inches, but are only about as big around as a pencil and then turn yellow and die. What is the problem?

The cucumbers might be shriveling because they have not been properly pollinated. Here is an article that will tell you how to hand pollinate your cucumbers:
https://www.gardeningknowhow.com/edible/vegetables/cucumber/hand-pollinating-cucumbers.htm
Happy gardening!