On our site we have a spare allotment its been empty for about 2 yrs or more ive been thinking about taking it over as its only £20 a year rent, to grow potatoes and courgettes sweet corn beans and soft fruit etc , which takes up space on the ones we,ve got ...things which sell good ... My partner and I have two... 75 ft by 25 ft roughly combined (£40 a year ) I retire in just over year so have been planning on making and selling jams and preserves at a local carboot which is held 100 meters away from the allotment site , Plus the cottage adjoining said we can put a honesty box table to sell any excess, along side their egg one .we are growing a lot fruit for this purpose which is taking up a lot of room on the ones we got now So planning to move a lot of the fruit over to the new one , So my question is what is the minimum years i need to leave as a crop rotation in the vege mentioned mainly the potatoes.?