cardboard as a mulch when digging a new area

Question

I have been told to use cardboard during the double digging process and was wondering if you have any information…..so digging a new, untouched previous area covered in general grass….remove grass first then put sods to one side then dig to a spade depth and put soil to one side….a trench has been created so then fork over the bottom of the trench….THEN put sods back into the trench but overturned so that the grass is facing down….then put cardboard down on top of sods…..finally cover with both soil and soil conditioner taken from a second area that has been dug over previously……can you tell me how correct is this method, have a missed something, or is it totally incorrect….hope you can help

Answer 1

Usually the cardboard is used to smother the grass without digging the grass out first. If you remove the grass manually, you don't need the cardboard. Or you can kill the grass with an herbicide. Once the grass is removed you can "double dig" by making 10 inch trenches, removing the dirt and filling the previous dug trench. Do that all across the bed, filling the last trench with the soil from the first trench. Here is more information:
https://www.gardeningknowhow.com/special/starting/how-to-build-a-flower-bed-starting-a-flower-bed-from-scratch.htm

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/double-digging-soil.htm