Q.Why Do My Container Cucumbers Suddenly Look So Bad?
For the very first time, I planted cucumbers this spring in a large container filled with new potting soil and was excited about it. If I put vegs out in the main garden, insects will devour them. For a while they looked fine. We have had a hot dry summer so far. All I could do was water faithfully every day or two with a sprinkling can. Recently their color began to look a bit yellowish, maybe from intense heat? Today we had a big heavy storm, breaking the droughtlike conditions. But now the plants have root exposure from the rain. I have leftover pot soil I can put around them. But is there anything else I can do? Thanks

Certified GKH Gardening Expert
This is a sign of overwatering. The soil does need to dry out completely down to 1/3 of the soil between watering. Even if the top is dry, it will be necessary to check down into the soil with a finger, or a moisture probe.
It might be the case that the plant withers away, since it is unable to get nutrients from the roots to the top of the plant. If this happens, you may have to replant. Otherwise, give it the best care possible to try and bring it back to health.
These aricles will help:
https://www.gardeningknowhow.com/edible/vegetables/cucumber/cucumbers-in-containers.htm