Calculate how many cubic yards and bags of mulch or garden soil you need for your landscaping beds.
A depth of 3 inches is optimal for weed prevention and soil moisture retention. Avoid piling mulch higher than 4 inches, and never pile mulch against tree trunks (known as a 'mulch volcano') as it rots the tree bark.
One cubic yard contains 27 cubic feet. Therefore, 1 cubic yard equals 13.5 bags of 2.0 cu ft mulch (round up to 14) or 18 bags of 1.5 cu ft mulch.
Organic bark and hardwood mulch decompose and should be refreshed annually with a 1-to-2-inch top layer. Cedar and cypress last slightly longer (up to 2 years) due to natural rot-resistant oils.