Cucumber plants can in fact be overwatered and it will be important to look for signs overwatering so you can grow them properly. If the leaves on your cucumber plant start to turn yellow, this can be a sign that they are getting a little bit too much water. Eventually the leaves on this plant will become very brittle and at some point defoliate completely.
If one of these plants is overwatered, it can fail to yield any cucumbers at all, which is why it is so important to make sure that your cucumber plants are getting the proper amount of water on a regular basis. In the event that overwatering occurs, you will want to immediately switch to another method of watering, such as a drip irrigation system.