Hello Casper,

Thank you for your seeing that these areas aren't used by tractors. They're used by a motorized plow at most.
I did what I believed was best. 
The definition of an Allotment on the wiki seems to be quite ambiguous. The portuguese wiki is more suggestive of the tag applying on urban vegetable gardens as it describes the scope as "hortas urbanas" which translates as urban vegetable gardens.
I guess the tag documentation should be further developed and clarified in my opinion. There can also be different portuguese standards at play. I will inquiry the Portuguese telegram group about this.
The allotment description seems to include the scenario where a family owns or rents the plot to grow their food, which seems to be the case of these plots adjacent to the houses. On the other hand it seems to fail to embrace the access tag that should be used to define if the allotment is for private use or communal. But again, an allotment doesn't seem to include the case for private land use.
It's confusing and in my opinion it would make sense to propose a landuse=vegetable_garden which encompasses both realities to coexist.
I'm okay with adopting leisure=garden as suggested but keep in mind these areas aren't used as leisure and I'll also hear what the portuguese community has to say.

Take care
Emanuel