Kale and collard greens are both very nutritious, and one plant of either produces a lot of leaves. They can also be left outside all winter (unless you get rabbits). And while kale needs to be blanched if you decide to harvest and freeze the leaves, collard greens don't require blanching. Their leaves can also be laid flat, one atop the next, which means they don't take up much space in the freezer. Aphids and cabbage whites are both drawn to these plants, so I would suggest covering them with netting. The alternative, for aphids, is to wash them off with water as soon as you see them and repeat daily until they're gone. I've seen videos on YouTube that suggest a mild soap and water solution but don't listen to them. The soap strips the leaves of their natural coating and kills them. Found that out the hard way. Cabbage white caterpillars are ravenous and need to be hunted and squished, but netting will keep the butterflies from laying their eggs on the leaves.
I agree with the pole bean suggestion, especially if you can manage a half dozen plants. They are great producers. I've had shelves of my freezer jammed full of them, but I usually have a 10' row with plants spaced 6" apart.
You need a large container for tomatoes. One site I visit recommends a 5-gallon pot. There are low acid varieties. Roma tomatoes are one, and Ace 55 looks like a good one, although it's not something I've tried.
= new reply since forum marked as read