Both watermelons and cucumbers are in the same family called “Cucurbitaceaeâ€.
The growing needs of each are also quite similar, including the same overall amount of sunlight and space.
Watermelons and cucumbers need a lot of space for their vines to spread out; having something like a cage or a fence in the area where you are growing them can help to manage their size.
Both of these also need consistent moisture in the area where they are growing and it is must also be rich with all the right nutrients which will help them to flourish and grow to a size that is healthy.