From P2P Food Lab
Arguments in favor
- Initial digging until good soil structure is obtained 
- Early morning or evening in spring or autumn. Dig when soil is evenly moist. Soil is too wet when it sticks to the spade. Soil is too dry when it cannot be penetrated by spade or when it crumbles in the palm or your hand. 
- Jeavons, J. (2012) "How To Grow More Vegetables", p. 19.
- Jeavons, J. (2012) "How To Grow More Vegetables", p. 18.