Hope people don't mind me digging up threads... I had the same question and this thread was first on Google. I think I'll stick around too, this forum looks very interesting. So far looking up what squash will grow on a trellis, it seems any squash will. I intend to have some on the ground while others climb, so I'd rather the climbers do so on their own. I know Cucumber and Watermelon plants have tendrils from growing them on a trellis, but I don't know about others. If anyone grows squash this year, could you post which ones have tendrils? Funny space was mentioned. I don't have much space (4x8 cinder block raised bed) so I grew 5 plants in a 4x4 area of different types with 3 seeds per mound w/o thinning them as a test because I use to do it a little more spread out in Nevada. The watermelon grew up the trellis and grew a green golf ball, the cucumber also grew up a trellis but produced a lot of fruit, the straight-neck & zucchini turned into bushes turning out a lot of zucchini and a few straight-neck, and the pumpkin produced no fruit. Learned that watermelon and pumpkin need their space, but cucumbers need very little space with a trellis. Zucchini have a tendency to outgrow the competition and leaving multiple plants per hill let me leave one to grow a big zucchini while the other 2 grew small ones ( I shred big zucchini for bread and cake ). I had corn in among the squash and on the other side and in the cinder blocks I had sunflowers, peas, tons of lettuce & spinach & carrots, a huge tomato plant and a new artichoke. All except the corn grew well. It's amazing what can grow in such a little area. BTW sunflowers have huge roots and will take all the dirt out of a cinder block, but they make a great trellis for peas.

Last year I grew three cukes on a 4' wide trellis, and had more than we could eat fresh, give away and pickle. For your 4x4' zucchini bed, I think you could do 2-3 plants if you give them room to sprawl beyond the borders of the bed. I'd think hard about doing more than 1 or 2 unless you've got multiple varieties, though because they are so prolific. I don't have much experience with melons, but I think it depends on your variety. I'd imagine that large-fruited melons with long vines would need more space per plant, whereas some melons grow 1-lb fruits and only 3-5 foot vines, so you could get away with closer spacing on those.

I somewhat agree with lazygardens in that the Armenian Cuke is the best for this area and also the taste. As he knows the Armenian is actually a cantaloupe with a bland taste for a melon, but tasty as a cucumber and oh so crunchy. I do not have issues with the heat getting to my cukes as long as I pick them. Near the end of the season I have more problems with aphids instead. If you want a pickling cumcumber I would go with SR58. There are others of course. I plant either straight 8s or straight 9s for an eating cucumber. You can also plant cucumbers in August and get a fall crop, but it will not be much of a harvest and the cucumbers will be much smaller. I did not feel that it was worth my time, but I had to try it once just like I did with a fall crop of beans. Lazygardens is on the money on the trellis and the squash. Let the squash run on the ground. I find myself that the zukes do best in this heat verses the other types of squash. I mean you can grow them all, but the zukes just do better in the heat. Whatever you do please do everything from seed. Then you know what you are getting.

I raise them on cattle panels, it works great. I don't do that arch thing, I just have them on their sides, with 3 t-posts per 16 ft panel holding them up, and wired on. They're surprisingly stable. I've done kabocha, butternut, and some of the smaller Asian squashes, maybe up to 8 lbs? Never had one fall off. One thing to watch, though, is if the fruits start to grow in side the panel holes - move them out quickly, or you'll never get them out. The further apart you put the panels, the better - 4 ft apart would be the minimum, 6 foot better. I the squash vines every 3 feet.