Wonder how much good stuff you need?
To find how much you need, just multiply the container's length x width x depth (e.g. basket, bed, garden, lawn). Remember to keep it all in the same unit. For instance if your bed is only 6'', use 0.5 ft! There are 27 cu ft in a cubic yard, and 1000 L in a cubic meter.
Here is a great tool to help you with volume calculations: