Garden Makeover: How Much Soil, Mulch, and Gravel You Need

Garden renovations get budgeted badly because they mix materials that are measured differently: soil by settled volume, mulch by coverage depth, and gravel by compacted layer. This guide splits an example garden into 3 zones, calculates each one, and builds the shopping list — the same process works at any size.

The example garden, by zones

Zone A — Planting beds	10 m² (110 sq ft) receiving 10 cm (4 in) of improved soil
Zone B — Mulch cover	The same 10 m², with 5 cm (2 in) of mulch on top
Zone C — Gravel path	6 m² (a 60 cm × 10 m path) with 7 cm compacted

Zone A — The soil (buy the settling, don't regret it)

Volume: 10 × 0.10 = 1 m³. Freshly placed soil settles 15–20% with the first waterings, so buy 1.15–1.2 m³. From ~1 m³ up, quote bulk delivery (by the m³ or yd³) as well as bags: 1.2 m³ equals 24 fifty-liter bags, and bulk usually costs much less per liter. If the beds are for vegetables, remember the mix: half topsoil, 30% compost, 20% aerating material — the soil calculator gives you the total volume and this ratio turns it into a shopping list.

Zone B — The mulch (the layer that saves watering)

Volume: 10 × 0.05 = 0.5 m³ = 500 liters → 11 fifty-liter bags with a 10% margin. Choose the type by zone: bark for ornamental beds (lasts 2–3 years), straw for the vegetable garden (one season). Apply it after planting and a good watering, and leave 8–10 cm clear around every trunk. Budget the top-up too: ~30% of the volume each year. → Mulch calculator

Zone C — The gravel path

Volume: 6 × 0.07 = 0.42 m³; with 15% compaction, ~0.5 m³ (about 800 kg of decorative pea gravel). Dig 8–10 cm, lay geotextile fabric (6 m² + overlaps = 7 m²), contain the edges with edging or stone, and compact in two passes. Without geotextile, half your gravel will be inside the soil within two seasons. → Gravel calculator

Shopping list and work order

Improved soil	1.2 m³ (bulk, or 24 × 50 L bags)
Mulch	11 × 50 L bags
Decorative gravel	0.5 m³ (~800 kg) + 7 m² geotextile

Recommended order: the path first (it's the dirty work that tramples everything), then the beds and their soil, a settling watering, planting, and mulch last. One weekend for the path and another for beds and planting is a realistic pace at this size.