What Kind Of Dirt To Buy For Garden

Garden soil, on the other hand, tends be made up of topsoil and a mixture of other materials and nutrients (compost and fertilizer) designed for specific types of plants. It tends to be more expensive than topsoil. In general, use potting soil for container gardening, garden soil for planting in flower or vegetable beds (you have to mix it with existing soil), and topsoil for larger projects or if your lawn or garden is in need of greater soil volume (for instance, if there's been soil erosion from strong winds or heavy rains).

Q: How do you add topsoil?

One good reason you may need to buy topsoil: to replace soil lost to erosion. Photograph by Matthew Williams, from Hardscaping \10\1: Erosion Control. — Above: One good reason you may need to buy topsoil: to replace soil lost to erosion. Photograph by Matthew Williams, from Hardscaping 101: Erosion Control.

A: Ideally, you should till the soil that's already in your garden (especially if it's compacted) and add a 3-inch layer of blended topsoil, tilling it all together again to create a 6-inch-deep surface layer; this will best mimic real topsoil. "You do not want to simply lay a three-inch layer on the surface of a soil and attempt to plant into that layer," advises Dr. Murphy. "Creation of artificial layers almost inevitably creates drainage problems. Roots may proliferate in that layer and never grow deeper into the mineral layer." Spring or fall, when rains keep soil moist and encourage biological activity and decomposition, are the best times to add topsoil.

Q: Do you need to add anything else to store-bought topsoil?

Above: See more at Walled Gardens: An Organic and Picturesque Plot at Old-Lands in Wales. Photograph by Britt Willoughby Dyer.

A: "Probably not compost, since most blended topsoils and bagged topsoils already have or are composed of compost," says Dr. Murphy. As for fertilizers, you'll need to have your soil tested to find out what nutrients your soil could use more of.

Q: Is it necessary to buy topsoil at all?

Above: Amending your existing topsoil with compost is a more sustainable and better option than hauling in store-bought topsoil. Photograph by Jim Powell, from Composting: Are You Obsessed?

A: If you simply need to increase soil volume—whether it's to replace soil that has eroded or to even out property or to create a garden from scratch—then yes, buying topsoil is an inexpensive way to do it. But if you're interested in encouraging a healthier, more fertile topsoil, according to Dr. Murphy, amending what you have with compost is preferable to buying topsoil. "The more we can re-create natural topsoils, the less fertilizer input is needed—and long-term sustainability can be achieved. For example, it has been shown that very old lawns require less fertilizers and less irrigation," she says. "In most cases, improve what you have with soil amendments, unless you specifically need greater soil volume."

Do you have a question about your first garden? (Or your second or third or fourth garden)? Let us know what they are in comments section below, and I'll try to answer them in upcoming installments of Your First Garden. In the meantime, find more beginner gardening lessons here:

Landscaping Ideas: 11 Design Mistakes to Avoid
Landscaping 101: How to Deadhead Flowers
Houseplants 101: How to Propagate Plants