Ok, I'm considering an allotment(I know its a nightmare to get on sites).
How much work are they and how productive can they be if you're clueless?
Had one, sometimes two, allotment plots for years. (And miss them desperately.)
Three years in, they can be
VERY productive - keeping a family cheaply virtually self-sufficient in seasonal veg and soft fruit, with plenty of glut surplus for the freezer, friends, neighbours, or the compost heap. Three years in, you've worked out what grows well on your patch, your rotation is working, and the soil is in rude health.
By then it's pretty cheap to run, and more than pays for itself. By then the labour follows a pretty predictable seasonal rhythm; mostly months of regular tasks of tick-over maintenance, with short periods of very intense labour.
It's not so much the amount of work that is difficult, but the regularity - for 2-3 years I kept
TWO full-size plots going successfully. A Sunday spent on the plots, with one or two extra evenings a week at times of sowing, harvesting, and preparation.
But - there's a catch in all that.
. Three years in.
AFTER an enormous investment in clearing wilderness and making it fertile. THAT'S the bugger. Get past that, and an allotment is an addictive dawdle. Hmm, correction - it's addictive, and you THINK it's a dawdle, because you've internalised the rhythm, and it's a wonderful satisfaction.
The only reason I know that, is that (at the time) the council would only allow new tenants a half-plot. When that was working well, they'd let you the other half. A good way to start - get the satisfaction of a working half plot, and build on your success.