Correct Fertilizer Ratio?
I received this question to my personal email today from Barbara Card of Amesbury, Mass., and I think it’s a good one to answer so everyone can see:
“I know organic fertilizers are the way to go, and I’m hearing that a lot of landscape companies are using organic fertilizers because they cost less, but I’m on a Conservation Commission here in Massachusetts and am trying to be very specific about the ratios of phosphorus to nitrogen to whatever else is in lawn fertilzers. What is the best ratio, and mix, and are all organics balanced correctly?”
MY ANSWER: Great question and one that’s impossible to answer without a soil test.
I can tell you that from a pure uptake analysis, grass uses nitrogen, calcium, potassium and phosphorus in that order and that most packaged fertilizers contain too much phosphorus and not enough calcium in their ratios.
Good organic fertilizers generally cost more than chemical fertilizers. If an organic fertilizer is really inexpensive, you need to understand if is a) truly organic, b) if is made from human biosolids or c) some other low grade waste product.
Folks who are really focusing on addressing specific soil needs will often apply bulk nutrients that are often less expensive. If you review these earlier posts, you’ll find that information: www.safelawns.org/blog/index.php/2009/07/natural-fertilizers-part-i/ and www.safelawns.org/blog/index.php/2009/07/natural-fertilizer-part-ii/.