The first step to creating a garden is preparing the planting bed. After turning over the top layer of soil, amending it with nutrients or adding to its depth are potential steps in the process. If you're building a raised bed garden or planting in containers or pots, you'll be starting from scratch. Topsoil and garden soil are the two best suited for growing edible and flower gardens, starting and maintaining lawns, and planting trees and shrubs. Choosing the right soil for your project saves you time, labor and cost.
What Is Topsoil?
Topsoil is the uppermost layer of the earth's crust composed of clay, sand and silt. It consists of minerals broken down from different types of rock, wood, leaves and other organic materials. It is active with organisms, microorganisms and bacteria working to break down solids into nutrients that support all plant life.
What Is Garden Soil?
The ideal soil composition for gardens is loam consisting of 40 percent silt, 40 percent sand and 20 percent clay. Garden soil has acidity and alkalinity balanced for specific plant growth along with minerals and nutrients readily available to feed plants. Garden soil is topsoil amended with organic or inorganic fertilizers to support edible, ornamental and landscape plants.
Topsoil vs. Garden Soil
Topsoil is graded according to the degree it been processed along with any specialized organic material it contains. It may be screened or unscreened and contain higher percentages of sand or clay. Unscreened topsoil includes small rocks, sticks, woods chips and other organic solids. It does not contain inorganic fertilizers. Topsoil is sold in bulk by the cubic yard and cubic foot with a 40-pound bag ranging in price from $2 to $5.
Garden soil is a mixture of screened topsoil broken down into uniform particles and consistency with nutrients immediately available to plants. Color, particle size, and consistency differ according to source, but the end product is a ready to use, crumbly mix mostly free of solid material.
Garden soil may be labeled organic or include inorganic fertilizer, but it is not graded according to quality or type. It can be purchased by the cubic yard and is readily available at garden centers in bags at prices ranging from $2.50 to $15 per cubic foot.
Graded by type
No inorganic fertilizer
May include inorganic fertilizer
Includes organic material
Includes organic material
Clay, silt and sand percentages vary
Screened or unscreened
Particle size varies
Uniform particle size
$2 to $5 per cubic foot
$2.50 to $15 per cubic foot
When to Use Topsoil vs. Garden Soil
Good quality garden soil is more expensive than topsoil, although some specialty topsoils, like mushroom compost, can get pricey.
Standard topsoil mixtures are rated for specific landscaping projects such as planting lawns, trees and shrubs and flower gardens. It works well to fill in holes and level uneven lawns and can be added where existing topsoil levels are insufficient to support plant growth. When building a raised garden bed or growing a container garden, topsoil can be used as a lower layer with garden soil on top. Topsoil is practical and less costly for large garden projects that require cubic yards of soil.
Garden soil can be added to long-standing flower and vegetable gardens to replace nutrients plants have used up. This is a good choice for the top layer in raised beds and container gardening. It is already broken down to drain well and includes nutrients immediately available to plants.
When you turn over topsoil for a new flowerbed or vegetable garden, the existing topsoil layer is very likely to contain all the nutrients and minerals plants need to grow well. You may need to adjust the pH level or amend with some organic compost or mulch, but most topsoil is adequate for a first in-ground garden. If your layer of topsoil isn't deep enough, either a higher grade of topsoil or a layer of garden soil can be added.
Frequently Asked Questions
Is it possible to grow plants in topsoil?
Yes, you can grow plants in topsoil as long as the soil extends to the depth needed for the plants you want to grow and has the correct pH level.
Should you use garden soil or topsoil in a raised bed?
A good quality topsoil can be used as the bottom layer in a raised bed, but an 8-inch layer of garden soil on top provides superior drainage and nutrition for vegetable plants.
What goes down first, topsoil or garden soil?
Topsoil should go down first before adding garden soil to raised beds, container gardens, pots, and hanging baskets. Use topsoil to build depth before adding garden soil.