Soil pH, beds, fertilizer key to landscape success

By: By LSU AgCenter Horticulturists Dan Gill, Kyle Huffstickler and Allen Owings
The LSU AgCenter has been promoting research-based best management practices in the home landscape for several years to inform residents on how to properly manage their landscape plants. Many problems associated with landscape plants can be overcome easily if proper practices are maintained.

Inadequate preparation of landscape beds frequently tops the list of problems with ornamental plants. But home gardeners also need to be more aware of soil pH and related issues in addition to how to use fertilizer properly.

Improper bed preparation leads to many of the problems with home landscape plants in Louisiana. With high annual rainfall and poorly drained native soils around much of the state, proper bed building is critical. Even with dry weather patterns these days, Louisiana still receives considerable rainfall.

We need to make raised beds — normally 6-8 inches high. Anything that can be done to improve internal drainage of soil and help with aeration and oxygen exchange in the root zone will aid in landscape success.

Raised beds help overcome root rot and related disease issues. Make sure your beds are adequately prepared before planting to help avoid problems later.

Soil testing is an important tool in home landscapes. We often see problems with ornamental plants due to improper pH. Most of the ornamental plants grown in Louisiana prefer a soil pH of 5.5-6.5. And some of our common landscape plants actually prefer soil pH in the lower end of this range. Examples include azaleas, gardenias, petunias, blueberries and vinca (or periwinkle).

Now is a good time to take soil samples and have them analyzed by the LSU AgCenter’s Soil Testing and Plant Analysis Lab in Baton Rouge for $10 per sample. You can find more information online at

Soil pH is raised by adding lime and lowered by adding sulfur, but these additions should always be based on the results of a soil test.

Proper fertilization is one of the key factors to be considered in combination with managing soil pH. It is helpful to know if your native soil has low, medium or high levels of fertility.

Do you tend to fertilize less than recommended or more than recommended? What are the fertility requirements of the different ornamental plants you grow?

The answers to these questions need to be considered to properly employ sustainable management practices in a residential landscape. Many times newer landscape beds need more fertilizer than older beds.

Spring is the generally accepted “best time of the year” to fertilize the vast majority of established ornamental plants, and it is better to broadcast fertilizer uniformly over a bed than to treat individual plants. So getting your soil tested now will put you in a position to get started on time next spring.

Preparing a landscape bed, checking and monitoring soil pH and correctly applying fertilizer go a long way in home landscape success. Consider all of these as you return to your landscape activities after a long, hot summer.

Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (La. 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to or

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