Tag Archives: soil testing

The Value of Soil Testing

A personal design is the first step to having a landscape and garden that enriches your life. After a high quality landscape installation, taking care of your plants is the key to a beautiful, long-lasting landscape. Soil testing is an important part of knowing how to feed your plants.

Why should I have my soil tested?

The soil test report gives you specific recommendations on the amount of fertilizer and lime (if needed) based on the type of plants. If the soil pH isn’t within the range of what your plants need, they won’t be able to absorb the nutrients in the soil and prosper. If they are under- or over-fertilized, the soil pH and fertility will also affect your plants’ health and their ability to resist pests and diseases. You can also save time and money by just using the amount of fertilizer and lime needed and also protect your plants and the environment.

In western North Carolina, our soils are naturally acid, which is a pH level below 7.0. Rhododendrons, mountain laurel, camellias, azaleas and blueberries thrive in the range of 4.8 to 5.5. Our cool season lawn grasses prefer alkaline soil around 6.0. That’s why lime is recommended to sweeten the soil. Other plants, such as many vegetables and some perennials, may also prefer alkaline soil. If you use plants that prefer alkaline soil, you probably will have to add lime to adjust the pH. Usually the optimum pH is between 5.5 and 7.5, since plant nutrients are reasonably available in that range.  Many vegetables, shrubs, annuals and perennials prefer a pH of 6 to 6.5. If you don’t know what pH your plants need, we can help.

Can’t I just apply lime and fertilizer without testing?

The risk of guessing how much lime and fertilizer is that you’ll apply too much of one thing and not enough of another. If you apply too much lime, you can raise the pH too high. It’s difficult, time consuming and results in more expense to lower the pH. Your plants may suffer as a result. The recommendation given in your soil test report should maintain the desired pH for 3 to 4 years for clay soil. Why not just do it right with a soil test?

How often should I have my soil tested?

Get a baseline test, preferably before planting. If you test before planting a new landscape, test it again the following year to see the effects of the amendments used in planting. Unless you have big nutrient deficiencies, require a big shift in your pH or have changed the soil in some way, have it tested every 2 to 4 years.

When should I take soil samples?

You can take samples anytime except for when the soil is very wet or has been limed or fertilized 6 to 8 weeks prior to desired testing. It’s also harder to take soil samples when the soil is really dry and hard.

If you send the samples to the state lab for testing, you may experience longer times for results from late fall through early spring, since this is the time that farmers send in their samples. Don’t let that deter you. If you need fast turn around, there are private labs.

Allow 2 to 3 months for lime to be incorporated into your soil and raise the pH.

If a plant foliage is discolored, you can also take soil samples for a problem diagnosis.

Can I do this myself?

Yes. Pick up the soil test boxes, instructions and forms from your local North Carolina Cooperative Extension office. The Asheville office is located at 94 Coxe Avenue. The materials and test results are currently free to North Carolina residents. You pay for mailing the samples.

If you prefer, we can provide this service for you for a nominal fee.

How should I use the soil test report?

The most useful parts of the soil test report are the recommended rates for lime and fertilizer. The report contains bar charts of the actual and optimum ranges for the pH, phosphorous and potassium. Refer to the last page for the rate of fertilizer. These recommendations are based on the needs of the plant group’s requirements.

There’s no need to be concerned with the “Additional Test Results” box.

Should I fertilize my trees?

In order to prevent damage to your trees from incorrect fertilization, it’s best to hire a certified arborist to determine the correct needs for your trees.