For most of us, when it's time to fertilize our lawns we head off to the local lawn care and garden shop and begin looking at all the different fertilizer types. While browsing the bags and looking at the labels something immediately stands out. Every bag of lawn fertilizer has a similar number of markings on them, while the numbers are often different they often look something like 10: 2: 2. So what are these mysterious numbers and what do they mean?
What Do The Numbers On Fertilizer Bags Actually Mean
The numbers are the ratio values of the major nutrients which are included in all fertilizers. In order, these major elements are Nitrogen: Phosphorous: Potassium. These ratios are required by law to be put in a clear view for the customer to see and to compare with other fertilizer products. So our fictitious fertilizer example mentioned above with a ratio of 10: 2: 2 would actually equate to 10 parts Nitrogen, 2 parts Phosphorous, and 2 parts Potassium.
So now that that's sorted out, the next question often brought up is "why don't all the numbers add up?". Adding up all the parts of our fertilizer above clearly shows a total of 14 parts - or 14%. Leaving another 84 parts or 84% of the product unaccounted for. The answer is that the rest of the fertilizer is made up of fillers and sometimes minor nutrients.
Fillers In Fertilizers
Firstly, not all of the extra fertilizer material is filler, with good quality fertilizers they will contain several minor nutrients, often called Trace Elements. For good lawn care and to gain the greatest results fertilizer it's always best to purchase a fertilizer that contains Minor Nutrients as well. While they are often only present in tiny amounts, these Trace Elements are equally essential to maintain healthy grass. These Minor Nutrients are often things like Iron, Manganese, and many other essential items we'll discuss in another article.
Fillers are put into lawn fertilizers for a very simple reason, they are there to dilute the main ingredients and to bulk them up. This is done with the end-user in mind and allows for a much safer application of fertilizer to the lawn. Without fillers, fertilizers would become extremely potent, and if they weren't applied correctly and precisely then the risk of damage to the lawn would be extremely high.
The results of bad application would be different patches of dark green grass while other areas are light green or yellow. This would follow any inconsistent application of the fertilizer where the heavy application would produce dark green patches and areas which missed out on getting enough fertilizer would produce a much lighter color.
Finally, any extreme excess of un-filled fertilizer put onto a lawn would also have the potential to severely damage or even kill a lawn if applied too heavily.
So the fillers really are there for a good reason, as an important safeguard for everyone who applies them, both homeowners and professionals alike.