The answers may differ depending on who you ask.
Here are some people who may have influenced your opinion up to this point: Lawn fertilizer manufacturers, wholesalers, hardware stores, lawn care companies, television and magazine ads, and last but not least your neighbor who gets 5 fertilizer treatments a year, every year.
So going down this list of people is it no wonder many people put too much lawn fertilizer on their lawns. Everyone that has helped educate and form many peoples opinion are making a living selling the merits of the more lawn fertilizing the better, and they have succeeded in many cases. (Yes, we are still talking about lawn fertilizers not Prescription Drugs)
There are however many articles from educational sources who firmly believe in less not more. Most of us however would not come into contact with these people or heard their views. Researchers in the University Horticultural Fields as well as those that study Organic Horticultural methods will tell you that less is better. Many will say that if you only fertilize once a year that it be in the fall.
So what makes up the fall fertilizer: the two major components that make up fall fertilizer are Phosphorus and Potassium.
Phosphorus helps develop strong root growth.
Potassium helps the grass to become resistant to disease, withstand stress during periods of drought and allows for the chemical process that helps develop strong new roots that are will be used to absorb water and nutrients.
A major component of lawn fertilizer of course is Nitrogen used to make our lawns nice and green and help develop healthy thick, long grass blades. Nitrogen is used as a larger percentage in spring and summer fertilizer. In fall fertilizer Potassium and phosphorus is more prominent. The percentages change from brand to brand.
I like to think of it as the potassium and phosphorous being the essential minerals and vitamins while the nitrogen is the steroids.
In order for a lawn care company to exist they have to make money (we can all relate to this). In order to make money they currently set up their annual service as treatments. The more treatments they can provide the more money they can charge.(makes sense, nothing wrong with that). Most sell customers on 5 fertilizer treatments. Over the years I have witnessed the amount of fertilizer that is distributed over people’s lawn in the summer time, and in many many cases very little is going on the lawn. They zip around the yard throwing a little bit of fertilizer around and then grab the weed spray for another treatment that day, maybe the most important treatment to many people.
During dry spells in the summer it is recommended that fertilizer be sprinkled with water or applied prior to rain in order for the fertilizer to not burn the lawn.
Well I figure if they are not putting too much on, probably nothing much going to burn the lawn. So not to worry about watering or the rain and remember, the second treatment that day is the weed spray, that is the one you are really paying (and praying) for, and you don’t want to wash that away.
So as long as you are getting your fertilizer in the fall and another shot of some in the spring you should be ok. Even better if you are mulching your grass as well.
The little bit extra fertilizer in the summer when the lawn is already under stress form the heat is not causing too much damage. Make sure you are not putting too much down, it really should be watered in. The lawn care companies still need to charge in order to stay in business and not loose money applying the more expensive weed control.
When the fertilizer with the larger component of nitrogen is spread on your lawn in the spring it will kick start your lawn into getting thick and green and you will have lots of fun cutting your thick spring lawn. That’s why I go easy on the spring fertilizer for my own lawn. The thick roots your lawn has developed will be able to absorb much nutrients to help the lawn look very healthy.
If you are mulching your lawn on a weekly basis it replaces having to fertilize your lawn too often. It will be receiving more than enough essential micro-nutrients from the organic matter of the decomposed grass clippings to keep your lawn healthy.
The key of course is having a proper mulching mower.
Over the years we have used a mulching mower for our lawn customers and when we were finished each week you could not see any of the clippings. If however you are cutting the lawn when it is too high, your poor lawn mower will never be up to the task. Sometimes as well that hearty spring lawn will be difficult to get thru, especially if there has been lots of rain. Unless you have time to go over it slowly with narrow cuts or or cutting it twice maybe a few bagging in the early spring may get your thru with out too much pain to your mower.
There may not be any right answer to how much lawn fertilizer you should apply, just get some down on a regular basis. The stronger your lawn the better off you are to help smother and block out the weeds.