Garden News: Now’s the ideal time to test your soil

If you’re waiting for spring to start planting your garden — especially a vegetable garden — now is the ideal time to take soil samples, says LSU AgCenter horticulturist Kiki Fontenot.

If you have more than one garden or have areas of your landscape that you reserve for different uses — vegetables, flowers, ornamentals or lawn — test each separately.

This will let you know how to best treat the soil for the particular type of plants you want to grow.

To take a soil sample, collect soil from six places in your garden, each about 6 inches deep. Mix these six samples in a bucket, and then remove about a pint or a sandwich bagful of soil. Send the sample to the Soils Testing and Plant Analysis Lab on the LSU campus.

You can find forms and more information online at or at an AgCenter office. Many local garden nurseries have soil boxes that contain the necessary forms. Cost for the test is $10.

The soils lab will provide recommendations to match your soil to your intended plants. Allow at least two weeks for your results to be sent back to you. Wait until you get your results before you apply fertilizer.

These results are very important because they will give you tons of information, Fontenot says.

The two most important results are your pH, which ideally for most vegetable crops should be between 5.5 and 7.0, and the levels of nitrogen, phosphorus and potassium (N-P-K) you’ll need to add to the garden to achieve optimum yields.

“Just guessing won’t help your plants,” she says. “Too much or too little fertilizer is detrimental to the crop.”

The money you’ll spend on a soil sample is invaluable to the success of your garden. Soil testing only needs to be done every two to three years in a home garden.

Upcoming events

The LSU AgCenter and the St. Tammany Master Gardener Association will hold the 2014 Northshore Garden Show and Plant Sale March 14-15 at the St. Tammany Fairgrounds in Covington. Gates will be open from 9 a.m. to 6 p.m. on March 14 and from 9 a.m. to 4 p.m. on March 15. Admission is $5 for adults.

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