Cucumbers? I'm not sure how it would work with a plant that vines out like cucumbers, watermelon, and squash. Are you looking to sell your surplus or are you simply growing for yourself? Plants that grow tall like tomatoes will require a large water reservoir. I've seen it done and the plants and tomatoes looked great, but they were in large buckets of water which will take up space. Spinach, lettuce, and other squat plants would probably be super easy though.