Honestly I've been trying to sq ft garden for years- came across my old plans on graph paper the other day, & oh, my

. Let's just say 'going by the book' was not terribly realistic.
Squash & corn are two plants that just take up humungous space. I've tried trellising & end up with vines that pull down anything I use- and last year had a huge metal structure. Heavy stuff that bent pipes like they were q-tips. (I had tromboncini rampicante zucchini take over the neighbor's elm tree on its way up & out! It is embarassing to have the neighbors ask why there is what appears to be zucchini 30 ft up in their tree!)
I'm growing sprawlers as sprawlers from now on, & devoting an entire bed to corn. Everytime I try to keep stuff in its own little sq ft, even soi-disant well-behaved vegetables like broccoli, everything goes mad, gets in each others space, & becomes impossible to care for properly. I may have to grow fewer varieties of veggies, & have more of some than I'd necessarily need, but it is just too much to care for, all mingly & companion-y. If I need to bt my cabbage, I just want to load up the cabbage, not pick & wiggle through 40 ft of beds trying to find them hiding under the cucumbers.
(Don't get me wrong, I'll still stake & grow some stuff vertically, but after watching 5 israeli honeydews fall from the vine & split, even supported in nets, I'm letting them do their thing on the ground. Woodlice are not as bad as dropping on a ripe melon!)
I feel like such a failure- the illustrations are so pretty, the 'three sisters' (corn, squash, beans), etc, so romantic a notion- it's what my goal was. But c'est la vie, I gotta do what works.