Mulch vs Compost — Which One Does Your Garden Need?

Mulch and compost are both essential for healthy gardens, but they serve very different purposes. Using the wrong one can harm your plants.

What is Mulch?

Mulch is a protective layer spread on top of the soil. It does not mix with the soil. Its main purposes are:

• Retain soil moisture (reduces watering by up to 50%)
• Suppress weed growth
• Regulate soil temperature
• Prevent soil erosion
• Improve garden appearance

What is Compost?

Compost is decomposed organic matter that gets mixed INTO the soil. Its main purposes are:

• Add nutrients (nitrogen, phosphorus, potassium)
• Improve soil structure
• Support beneficial microorganisms
• Increase water retention in sandy soils
• Improve drainage in clay soils

When to Use Each

Use Mulch When:

You already have established plants and want to protect the soil. Apply 5-10cm thick layer in spring or fall.

Use Compost When:

You are preparing a new bed or replanting. Mix 2-5cm of compost into the top 15cm of existing soil.

How Much Do You Need?

For a 10 square meter area:

• Mulch (7cm thick): About 0.7 m³ = 280kg of wood mulch
• Compost (3cm thick, mixed in): About 0.3 m³ = 225kg of compost

Use our weight calculator to get exact amounts for your specific area.

Common Mistakes

• Using mulch as compost: Mulch does not break down fast enough to feed plants
• Piling mulch against tree trunks: This causes rot. Keep mulch 10cm away from stems
• Using fresh manure as mulch: It can burn plants. Let it age for 6 months first
• Too much compost: Can over-fertilize plants. Stick to 3-5cm mixed in