Beats me!! :>) Sounds like it means an allotted parcel of gardening space.
]
1. The act of allotting: initiated the allotment of ration coupons. 2. Something allotted: had already used up their weekly allotment of flour. 3. A portion of military pay that is regularly deducted and set aside, as for the payee's dependents or for insurance.   

A