Mulch Calculator

At the recommended 3-inch depth, 100 sq ft needs about 25 cubic feet or roughly 0.9 cubic yards. That is about 13 standard 2-cubic-foot bags. One cubic yard covers approximately 108 sq ft at 3 inches deep.

Apply organic mulch (wood, bark) 2-4 inches deep. The standard recommendation is 3 inches. Less than 2 inches is too thin to suppress weeds effectively. More than 4 inches can suffocate plant roots and create moisture problems. For gravel and rock, 2-3 inches is typically sufficient.

Bulk mulch is significantly cheaper for larger projects. A cubic yard of bulk hardwood mulch costs $30-45 delivered, while the equivalent in bags (13.5 two-cubic-foot bags at $4 each) costs about $54. The break-even point is usually around 3 cubic yards. Below that, bags may be more practical despite the higher cost.

The best time to apply mulch is late spring after the soil has warmed. This helps retain moisture through summer. Fall mulching protects plant roots from winter freeze-thaw cycles. Avoid mulching too early in spring, as it can prevent the soil from warming and delay plant growth.

Organic mulch (wood, bark) decomposes and should be refreshed annually or bi-annually. You typically only need to add 1-2 inches on top of existing mulch. Rubber mulch, gravel, and rock are permanent and only need occasional topping off. Cedar mulch lasts longer than hardwood due to its natural oils.