I grew yellow summer squash in a single square foot last year with no problem at a square along the outside edge of my raised bed. The fruit stay tucked near the stem and you should harvest them early. I'm going to try spaghetti squash (winter squash) on a corner square this year and just keep training outward. I'll have overflow but at least I wont need to give up another square just because the plant wants to stretch out a bit.

Thanks LoneCowboy,
Maybe I'll try to find a compact variety and let it hang over like you did with yours.

I've grown patty pan, sunburst, and black beauty zucchini for years and they certainly can be grown in 1square foot. I grow mine on those green t-posts. Works like a charm all the time.

Snibb,
Glad to know that you are able to grow it. Could you expand a little on what it means to grow on a t-post. Are you using those as your trellis frame, or in some other way. Also, I assume you have to do a decent amount of pruning?
Thanks!

I have used a small tomato cage. As the leaves grow, push them up thru the wire cage.

tbick...it's all on my blog in the photo gallery. I just saw about 3 or 4 pictures of what(and how to do it)I mean by a green t-post. It's not really a trellis system-it's just a lone t-post. Someone on this site had a set of several pictures they got from my site several years ago that also showed it. And no, I have absolutely no pruning to do. The only thing I do differently now is use velco instead of rope.

I usualy put it in the corner of the bed on the south east corner. I plant anything that needs evening shade north of it. I plant about 8 to 10 inches from the corner. While it does not give a whole lot more room. It does give more than if it were planted in the center.

I plant a row of 3-4 in a 1' strip on the end of a bed with a trellis immediately behind them to force them out over the cinder blocks and onto the ground. In my climate, 4 plants could overflow a dedicated 4x4 bed by end of season.

I'm growing bush and vine winter squashes in the back squares of my garden (3' x 6'). The plan is for them to overflow the sides and then the rest can have my whole 5' x 15' twine trellis. I do find in my climate (hot humid central florida) that it is absolutely necessary to make sure the squash or other curcubits have plenty of air circulation so the plants and fruit don't mildew or rot.
I can't speak to their performance yet, but the bush varieties I'm trying are Burpee's Butterbush (like a butternut) and Early Acorn Hybrid. Both are reputed to do well and spread no more than 3ft. We'll see! The vine type are a Spaghetti and a heirloom recreation called Lakota (similar to a hubbard).