I have many cucumber vines, lots and lots of yellow flowers, and only one cucumber. I have caged my cucumbers to train them to grow upward and not spread out so far. They are in a planting box and inside a greenhouse. I water thoroughly every other day and run fans to keep the heat at bay. Plants look good but I do have a lot of yellowed and wilted leaves on the bottom sides of the plants. Am I overwatering?
Yellowing leaves can indicate a watering issue, to much or to little. It also may be a temperature issue. To hot of temperatures can stress the plant.
If the temperatures are above 85 degrees you may need to water twice a day. You need to actually feel the soil, it should be moist but not soggy.
Make sure the container is well draining.
Here are a few links for you to refresh you on the care requirements.