When we began preparing previously undisturbed, grassy areas conversion to new raised beds, we found that a “hula hoe” is best for easily undercutting the weeds and simultaneously loosening the soil. This helps create an ideal seedbed with minimum effort. Grasses and weeds are excised with minimal soil removal, and can then be added to the compost pile.
Today we found that one if the most important things to be aware of with double digging is that walking on the beds compacts the soil and undoes much of the good work. Fellow gardeners and visitors should be reminded to stay out of beds which have been prepared with double digging, and when planning the layout of the garden, we should make sure that garden paths are wide enough for people, carts and wheelbarrows to pass freely between the beds. It's also important to avoid placing heavy objects in a double dug bed; bags of soil amendments such as lime should be placed in a garden path while they are in use so that they do not compress the soil in a double dug bed. Ultimately, Good soil management creates a favorable environment for healthy root growth. Double digging reverses combats high soil strength that can inhibit the penetration of roots, resulting in poor plant growth. Excess soil strength can occur as a result of repeated exposure to foot and wheel traffic or naturally as soil with high clay or low organic matter hardens in droughty conditions, a process called ‘age-hardening’ or ‘hard-setting.’
(Corn roots in compacted (left) and non-compacted (right) heavy
clay soil from an experiment in Australia. Roots were not able to penetrate
the compacted layer so growth was stunted.)