Many thanks for your recent message regarding the practice of removing the lower leaves from sprout plants. I’ve certainly heard of this practice, but can’t shed any light on why it needs to be done in the midnight hour – perhaps you might want to consider moving allotments?!!
Lower leaves are often removed from the stem during autumn and winter to help improve air circulation, to allow the sprouts to fully develop and to lessen the likelihood of disease and rotting. Leaves are usually removed once they start to turn yellow and as the plant begins to reach maturity, but if you intend to try this method (during the day, preferably!), always make sure several of the healthy leaves at the top of the plant are left so it can continue feeding and growing.
Hopefully this helps and I’d probably also advise you not to approach anyone you see removing leaves at night!