Mulch is sold two ways, and the price difference between them is bigger than most people expect. Bulk mulch is measured in cubic yards and delivered loose. Bagged mulch comes in 2 cubic foot bags at the garden center. Since a cubic yard holds 27 cubic feet, one yard of bulk equals about 14 bags — and bulk is usually less than half the price per cubic foot once you pass two or three yards.
How deep should mulch be?
Three inches is the working standard. That is deep enough to block most weed seeds from germinating and to slow water loss from the soil, without smothering roots.
Use two inches when you are topping up a bed that still has good mulch underneath. Use four inches on paths where people walk, because foot traffic packs it down fast.
Going deeper than four inches is a common mistake. Thick mulch holds water against stems and can starve roots of air. It also wastes money — the difference between three and five inches on a 400 square foot bed is nearly two and a half cubic yards.
Keep mulch off the trunk
Piling mulch against a tree trunk — the shape people call a mulch volcano — traps moisture against the bark and invites rot and pests. Pull mulch back two to three inches from the trunk so the root flare is visible. The mulch ring should look like a donut, not a cone.
Bulk or bags?
Bags make sense for small jobs, under about one cubic yard, or when you have no way to store a loose pile. They are clean, easy to carry, and you buy exactly what you need.
Past two cubic yards, bulk wins on price and on your back. One cubic yard is roughly 14 bags to open, empty and dispose of.
One thing to check before ordering bulk: where the truck can dump it. You will be moving it by wheelbarrow from wherever the pile lands.
What it weighs
Dry bark mulch runs around 500 to 600 pounds per cubic yard, which is light as landscape materials go. Fresh or rain-soaked mulch can reach 800 pounds.
That matters if you are hauling it yourself. A half-ton pickup should not carry much more than one cubic yard of wet mulch, even though the bed looks like it could hold two.
When to spread it
Late spring, after the soil has warmed, is the usual timing. Mulching too early in the season keeps the ground cold and slows plants down.
Most organic mulch breaks down enough to need topping up once a year. Shredded hardwood lasts longer than fine bark; dyed mulch holds its color about one season.