The lab that Howard recommends can be found here:http://www.dirtdoctor.com/Soil-Testing-Lab_vq2119.htm
Texas Plant & Soil Lab
5115 W. Monte Cristo Rd.
Edinburg, Texas 78541
Phone Number: 956-383-0739
And here is discussion
about the lab and what they do that is so different from home kits and other labs around the area. And on that page, it says:
TPS&L uses the Carbon Dioxide (CO2) Extraction Method which is accurate for any soil type. This method duplicates the natural extraction method used by plants in the ground. Plant roots excrete CO2 in combination with soil moisture to form a weak carbonic acid that solubilizes nutrients for root uptake. Accurate soil testing which duplicates the plant's actual nutrient extraction method is essential for helping achieve maximum production potential from crops.
The Natural Organic Warehouse (NOW) offers Test Packages from Texas Plant & Soil Lab which includes recommendations and solutions to maximize production, beauty and profit for those doing commercial growing. Once the test results are completed, NOW can help with product recommendations ranging from a single product up to a comprehensive, long term program. Order your test kit today or call 888.998.9669 for more information.
You can ask that they send a copy of the results to Howard and he'll be able to tell you more about what the results mean and what you can, if needed, do about it.