Depends on what you mean by "low maintenance"
Whatever you plant, there's not a lot to do until its ready for harvesting. Some things are long term eg leeks, brussels etc over several months and others can be short term - radishes in 3-4 weeks time.
I find that all jobs take time - from digging over soil, digging in manure & compost, sowing (if at home to plant out - takes longer than you think, and then there's the aftercare while germinating), planting out and even the harvesting itself is a job and half, not to mention what to do with the produce if you have more than you need at the time (storage, preserving, freezing etc)
Then there's pest control (netting, picking off caterpillars etc that somehow got inside the netting :roll: , slugs, snails and more slugs :evil: )
Other crop protection might also be needed - watch out for late frosts, so you might need to erect a cloche or throw some fleece over, high winds so maybe some wind breaks/screen, and then there's the early frosts to watch out for, when crops are not quite ready but we suddenly have a nice warm sunny day, followed by clear skies & the first frost of the season :evil:
Feeding - I have to confess that I rarely give my plants extra feeding and rely heavily on earlier soil prepraration to carry them through their growing season. This is not a decision I made - more of a forgetting until it's too late. However, some people seem to go a bit overboard on this, preparing all sorts of concoctions which I have not found necessary.
Weeding & plot maintenance - they are my biggest jobs and I can spend more time titivating the plot up than actual gardening (but I'm working on this with lots of weed suppressing stuff :idea: ) Just be aware of your allotment rules and how much you can get away with - some have become savage just to turf people off to cut down on waiting lists if their plot has a weed out of place, or too much plastic, carpet or cardboard for their liking.
IF we get a hot, dry summer (ahem) :roll: you will need to ensure the plants have water (by sorting out some water conservation ideas such as mulching, or physically watering from water butts or hosepipe if it is allowed - and remember you would not be alone, so might have to queue for the standpipe) When the soil is really dry, I can spend up to 2-3 hours in one session giving everything a really good drenching and find it's still not enough.
Ideally I would love to spend all my time on the plots but employment pays the bills, so I realistically only have the weekends shared with housework, shopping & other things. In summer, I can snuck down early in the morning for about an hour before work. Most people prefer late afternoons & evenings but I'm an early bird. An average 10-15 hours in summer, and probably 4-7 hours in winter (when I do most of my digging & plot preparation, weather permitting of course
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Late spring/early summer seems to be my busiest time when its all happening at once (I actually find it stressful trying to juggle everything), followed by late summer when most things I grow are ready for harvesting and have to be dealt with.