Posted: 27/09/2014 at 21:03
Hi, Mozey, welcome to the forum.
You have my sympathy if you have chickweed on your allotment, although it's shallow rooted and can be pulled-up easily, it's still very persistent.
Unless you intend to planting on the ground you intend to dig, I would leave it and winter dig it, anytime after next month. This involves just turning the soil and leaving it rough for the frosts & elements to break down.