How much mulch do I need?
Multiply the bed area by the depth you want, keeping units consistent. For imperial: square feet times depth in inches, divided by 324, gives cubic yards. For metric: square metres times depth in centimetres, divided by 100, gives cubic metres. A 200 sq ft bed at 3 inches needs about 1.85 cubic yards. Always work in volume, since mulch is sold that way.
How deep should mulch be?
Two to three inches, or 5 to 8 cm, for most beds — enough to suppress weeds and hold moisture without suffocating roots. Go thinner around shallow-rooted plants and thicker only on paths. More is not better: deep mulch can stay waterlogged, encourage fungal problems, and in dry spells actually intercept light rain before it reaches the soil.
What is mulch volcano and why does it kill trees?
Piling mulch against a trunk, forming a cone. It traps moisture against the bark, invites rot and disease, encourages roots to grow into the mulch instead of the soil, and shelters rodents that gnaw the bark. Trees mulched this way often decline years later for reasons the owner never connects. Keep mulch clear of the trunk entirely — a doughnut, not a volcano.
How often should mulch be replaced?
Organic mulches such as bark, wood chip and straw break down and typically need topping up annually, though you usually add an inch rather than replacing the lot. Measure the existing depth first and top up to target — repeatedly adding a full layer each year is how beds end up six inches deep. Inorganic mulches like gravel do not decompose but do need weeding and occasional refreshing.
How do bags compare with bulk delivery?
A standard bag is typically 2 or 3 cubic feet, so a cubic yard is roughly 9 to 13 bags. Bulk is substantially cheaper per unit once you need more than about a cubic yard, and produces no plastic waste, but requires somewhere to tip it and the work of moving it. Bags win for small jobs and awkward access.
Does mulch type change the quantity or the outcome?
Not the volume calculation, but it changes performance. Fine mulches compact and can form a water-repellent crust; coarse chips drain freely but suppress weeds less well until thick. Fresh wood chip can temporarily draw nitrogen from the soil surface, so it suits paths better than vegetable beds. Cocoa mulch is toxic to dogs. Match the material to the bed and its occupants.