Actually, scallions are probably the most space efficient veggies I have planted.
You can get so many of them in a small area, but they do need to be started early.
Try some green beans. If they are bush variety, start a couple seeds every 2 - 3 weeks.m It will give you a constant harvest. Pole beans which can climb up a trellis nicely, produce almost continuously. They are nice because they, too, are very space efficient.
We did pole beans last year. I’ll put some in again.
Thanks.
L
I grew some Tokyo Turnips this year. They take up very little space, slightly more than carrots but are super easy to grow and can give you something to harvest in as little as a month or up to two months for larger turnips. They also like cold weather. The tops can be eaten as greens too. I just pulled a half dozen 2 inch diameter turnips yesterday and I started the seeds almost two months ago. I could have pulled some at 1 inch a couple of weeks ago.
For a 30 day harvest, my soil would have to be better as would my seed starting ability but this was my first year starting thing from seed. I don’t count that one time I tried to start a few tomato plants on the window sill.