Get the dirt on your dirt (soil)

Down here in USDA hardiness zone 8b, we’re counting down the days until our last frost date. Those of us with home gardening addictions took advantage of those ‘snow days’ in January to flip dreamy-eyed through seed catalogs* Punxsutawney Phil’s predictions be damned! Gardening time is almost here. Readers in hardiness zones with lower numbers have a bit more time to dream before getting out the garden gloves.

As much as you may want to hit the ground planting on your last frost date, you should make an effort to get to know your soil. The aboveground plant parts typically get all of the attention. They are beautiful and delicious. They photosynthesize! However, the glory of the shoots depends on the roots. Their hidden labor is often taken for granted, but in most cases the roots make up half of the size of the aboveground plant. The root system is constantly growing to increase the capacity of the plant to take up required nutrients from the soil. Because healthy roots are the foundation of healthy productive plants, it’s important that the roots of the plants you care about have the proper environment for growth and development.

Soil profile, USDA via Wikipedia

So, if you want healthy plants (from productive tomatoes to beautiful flower beds), then you should care about your soil. No, not all soil is the same. There are differences in type, texture, pH, and nutrient content. Different plants have different needs when it comes to these factors. Gardeners can add specific fertilizers, compost and other amendments to tailor their soil for their plants. As with all of biology and chemistry, it’s all about staying within an optimum range- too much of something can be just as bad as too little. Smart gardeners know better than to just start dumping every possible fertilizer and ‘plant food’ available at their local gardening center into their flower beds and garden plots. It can get expensive and be completely unnecessary.

Soil texture via Wikipedia

Now, if you are staring at your tilled garden plot or cleared flower bed and the only description you can give your soil is ‘brown,’ don’t despair. You don’t personally have to know the difference between clay and silty loam. The secret to getting the dirt on your soil is having it tested by a lab that specializes in soil testing. As professional or exotic as this may sound to you, it’s actually easier than you think. Contact your local extension agent to for details on the nearest testing facility near you. There’s probably a testing lab in one of the agriculture departments of the university closest to you. If you live in Baton Rouge, the Soil Lab at LSU will be more than happy to do the analysis for you for about $10 per sample. Check out the links below for more information on how to collect samples. If you don’t drive in to LSU every day, you can get a mail-in kit (contact your local extension agent or check your local garden center) that includes instructions, a form, and sample bag in a prepaid** priority mail box. Include on the form the types of plants you would like to grow (flowers, vegetables, etc.) and when your results are mailed to you, the soil lab will give you recommendations for fertilizer amounts and amendments to add for the best results. Soil testing is something that you should think about doing well in advance of planting so that you still have plenty of time to prepare your soil with any necessary amendments. If your green thumb is itching to get to work, then take a soil sample and get it tested to get the dirt on your soil.


*OK that was a bit overly nostalgic. This is 2014 and most of that dreaming and seed-ordering were done on-line.

**Postage included in the cost of the analysis.

References and Links:

LSU AgCenter horticulture Hints for Spring 2014:

Some great links from the Colorado State Master Gardener curriculum:


Plant nutrition:

Intro to soils:

Soil tests:


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