How Deep Should Topsoil Be for a Garden?

Garden soil should always be dark, crumbly and rich.

When you're starting a vegetable garden, you must start with the right list of ingredients. This begins with soil amendments.

Timing

Cornell University recommends that gardeners amend their soil the season before they begin their planting to give the nutrients time to disperse and sink in. Amend the garden in fall for an early spring planting.

Topsoil

The topsoil is the loose, crumbly layer of earth on top, where vegetables grow and take root. This level should always be rich and crumbly, rather than tight or clay-based.

Preparation

You should dig into at least 6 to 8 inches of soil when preparing the garden. This gives vegetables room for expansion and guarantees good drainage in the garden.

Amendments

You should add at least 3 inches of organic compost to this 6- to 8-inch layer of topsoil. Compost will increase drainage and richness in the soil to provide long-term plant nutrition.

References

• University of Illinois Extension: Illinois Vegetable Garden Guide: Step 5 -- Prepare and Care for Soil Properly
• University of Illinois Extension: Watch Your Garden Grow: Vegetable Gardening Basics
• Cornell University: Cornell Gardening Resources: Soil Basics
• Cornell University: Site and Soil