clintj wrote:
I got my TPSL report back and it stated that my lawn fertilizer recommendation would be as follows (lbs/1000 sq.ft.) 2.00 S, 4.25 N, 0.00 P2O5, 5.73 K2O. Are these numbers typical for a fairly new organic lawncare program? I have an approximate 10K sq. ft. yard and these numbers seem quite high. I know a 20lb/1000 sq. ft of dry molasses wouldn’t even touch these numbers. By my calculations I would need 17.7 bags per year of an organic fertilizer with a nitrogen rating of 6 to get my full 4.25lb of N within the year. 6% of 40lb bag = 2.4lb N 42.5lb of N required for my 10k yard. 42.5/ 2.4 = 17.7 bags!
The reason dry molasses wouldn't touch those numbers is that dry molasses is not a fertilizer. Organic products that have no protein source are not fertilizers. SCIENCE ALERT: THE FOLLOWING GETS A LITTLE SCIENCY...Molasses is sugar, not protein. Sugar is made up of carbon, hydrogen, and oxygen molecules. Protein is made of amino acids which have nitrogen. All animal life, including soil microbes, needs protein. When the microbes get protein, they create a byproduct which happens to be plant food. For mammals the byproduct is urine with urea, an excellent fertilizer. For birds the byproduct is uric acid which also fertilizes. For fish the byproduct is ammonia, another fertilizer. The final byproducts of blood, skin, hair, and feathers all are extremely high in nitrogen. That's the way Mother Nature designed it billions of years ago. Sugar, especially molasses, is not an important source of nitrogen.
The best reason to have a soil test is to understand the micronutrients in your soil. Sure the macro nutrients, NPK, are going to be low (usually). Normal organic fertilizers will deal with that. Sometimes it is necessary to adjust the chemistry of the soil to allow the microbes to thrive. These adjustments are usually made with chemicals, not organics. Those chemicals include lime, sulfur, Epsom salts, borax, and some others. Your soil apparently is alkaline - hence the recommendation for sulfur. I can tell you that your alkaline soil is several hundred feet deep and no amount of sulfur will ever dissolve all that limestone. As long as there is a quarter inch of limestone, your soil will have a pH of 8. Your best approach there is to simply grow plants adapted to high pH soils. Fortunately southern grasses like bermuda and St Augustine do well in our soil.
So I'm going to suggest you ignore the soil test results for N, P, and K and look more closely at the micro nutrients. If you did not get that test, then I would suggest getting another test if you really want to know. I would also suggest a different laboratory. TPSL was my favorite test lab before K Chandler passed away. Since then they have floundered and come back a little different. Now the best test lab in the country is Logan Labs in Ohio. Why? You can read their results much better than TPSL. The standard test at Logan Labs is $12 and will give you all the micros. TPSL cannot touch that same test for that price.
Here is a photo of a test of alfalfa pellets as a fertilizer. The alfalfa was applied in mid May, 2011 and the picture was taken in mid June. Note the improved color, density, and growth. This is what you should expect from organic fertilizer.
A 50-pound bag of alfalfa cost $12 last season. It was the cheapest source of protein on the market. The application rate is 20 pounds per 1,000 square feet. Of course you can apply it as often as your wallet will let you. One member on another forum applied soybean meal and milorganite at a rate of 50 pounds per 1,000 square feet, EVERY WEEK, all season long, with no ill effects.