Mulch, Soil, and Compost
How to use this table:
Step 1: Multiply length x width of area to be covered, to find total sq ft of area. Find the nearest number in the left column. To calculate space of round or triangular spaces, see page 2.
Step 2: Read across that line, to the column that displays the desired inches of mulch/soil/compost in its top row, to find the number of cubic yards of material needed.
Step 1: Area 50’ long x 20’ wide = 1000 square feet of area to cover.
Step 2: If desired depth = 3”, then 9 cubic yards of material is needed.
Note: 1 cubic yard = 27 cubic feet; 1 cubic yard = nine 3-cu-ft bags
Depth of Mulch/Soil/Compost in Inches
|50 ft2||¼ yd3||½ yd3||½ yd3||1 yd3||1+ yd3||2 yd3|
Common Mulches and Their Characteristics
|Bark chips; wood chips||Attractive; long-lasting; decompose slowly; hinder water and air movement if too deep; color varies by species and age of material.|
|Grass clippings||May contain weed seeds; must replenish frequently as clippings decompose; may mat down when wet.|
|Leaves||Contain trace elements; some mat down and hinder water movement; can be tilled in to add organic matter to soil.|
|Pine needles||Light-weight; decompose slowly; attractive.|
|Hay||May contain too many weed seeds to be useful as a mulch; sometimes used in food gardens.|
|Straw||Used primarily in food gardens; apply 6-8″ of loose straw mulch to control weeds.|
|Salt marsh hay||Usually weed-free; long-lasting; used primarily in food gardens; more available near coast.|
|Peat moss||Weed-free; may mat down and hinder water penetration; nonrenewable resource.|
|Compost||Short-term mulch; adds nutrients to soil when tilled in; variable product depending on what raw materials were used to make the compost.|
|Black plastic||Retains soil moisture; prevents most weeds; warms soil; used primarily in food gardens.|
|Clear plastic||Heats soil; weeds grow underneath, but not effective at killing all weed seeds in Maine.|
|Landscape fabric||Woven fabrics control weeds when laid under layer of bark; can hinder water/air movement.|
|Shredded paper||Decomposes in one season; use 6-8″ of loose shredded paper to control weeds; newspaper strips stick together if watered periodically.|
|Decorative stone||Permanent; heavy; does not always provide good weed control.|
From the GardenPro Answer Book; revised and updated by Lois Berg Stack, Ornamental Horticulture Specialist, University of Maine Cooperative Extension.