I can’t buy Greenland, but I can buy a green lawn.

“It’s Not Easy Being Green” – Kermit the Frog

Does grass need fertilizer? This question has caused me some inner turmoil for some time. Are we just unnecessarily dumping nutrients into the soil for no good reason? Do we have to have the greenest lawn on the block year round? Why do plants grow all by themselves in a forrest setting? Why does it appear that grass grows and is healthy under trees with little to no attention?
My daughter and I would often have this debate. She would make a statement like, “Why do homes and lawns need to appear neat and tidy? Why not let everything grow naturally with no management?” In her mind, a lawn that was composed of each weed variety in sand was perfectly fine. For some people, a green weed lawn is perfectly fine. Some weeds look very similar to our cultivated grasses. Furthermore, in the Summer when the rains come, pastures of Bahia are green and pretty. My neighbor has a lawn of perennial peanut that looks nice and sometimes I am envious.
I will cover some alternatives to traditional lawns later but I want to stop for a moment and recap my goal in writing this material for you. My goal has always been to help you have a nice looking lawn with minimal amounts of trouble and negative environmental impacts. I enjoy clean water as much as anyone else and that is the purpose of this blog, to help the average homeowner have a nice looking, green and healthy lawn all while having little to no negative environmental impact.
Therefore, it is my conviction that while at one time the Earth was naturally perfect, at this time, weeds, disease, pests, etc are a real and present reality. Our job as stewards of the Creation is to manage those factors that work against aesthetic beauty to create a beautiful place that is enjoyable to inhabit. This requires work and effort. And I believe we can have a nice place to live that is nice to look at without sacrificing reasonable environmental concerns.
So what is the key to having a nice looking lawn that we can enjoy and not unnecessarily polluting the environment? A reasonable expectation of a healthy lawn. Its really that simple. If you want your lawn to look like a golf course, be prepared to treat it like a full time job with many chemical and nutritional inputs. If you tremble at the thought of any imperfection whatsoever in your lawn, then you will spend most of your time disappointed and contributing to environmental hazard.
So if we can be content with a healthy, green lawn that looks nice, how do we get there? Once you get your irrigation system dialed in, then you should develop a fertilization plan. Fertilizer is useless without proper irrigation.

Choosing the Best Fertilizer

For a healthy Florida lawn, you must start with a quality slow release fertilizer. You typically will not find a good slow release fertilizer at a so-called “box store” but rather at some specialty shop. In Florida, each county has an extension of the University of Florida which can aid you in finding a place to buy quality fertilizer.
There are 3 big numbers on a legal fertilizer label that is sold in Florida. These three numbers represent the three macronutritents, NPK, or Nitrogen, Phosphorous, and Potassium. For example, a bag of 15-0-15 will have 15 unit of Nitrogen, 0 units of Phosphorous, and 15 units of Potassium. Each unit represents the percentage of that nutrient in the fertilizer bag. In other words, 15 units of Nitrogen would be equal to 15% of Nitrogen product in each bag, or 7.5# per 50# bag.
Ideally, you want a balanced fertilizer such as 15-0-15. Some situations allow for the addition of Phosphorous. In that situation, a 15-2-15 or similar is fine. Other turf blends are 16-0-8, 20-0-10, and 24-0-11. These are just a few examples of many possibilities. If you can find a blend that is labeled for 5-6 months, you will surely see a higher first number, Nitrogen, as you need more Nitrogen to last 5-6 months. I generally recommend a 25-2-10 or 25-0-10 that is about 90% slow release for up to 5 months. I like this blend since it will release small amounts of Nitrogen over a longer period of time, rather than just dumping high amounts of Nitrogen that is leached through the soil or lost to volitization in the atmosphere.
Why so much slow release? The reason is simple. All the problems you face in caring for your lawn and usually traced to three things: improper mowing height, improper fertilization, and improper irrigation. If you can resolve these three issues, most of the problems would simply go away. You would have less pest, disease, and weed pressure. Therefore, it is my recommendation, that the homeowner and professional alike should use a 4-5 month slow release Nitrogen product.

Fertilizer timing

Nitrogen is the driving force behind a green lawn. Many think that iron makes lawns green but this not the case. Iron is an important part of chlorophyll production, as is Magnesium, but these are parts to the equation. Nitrogen is needed in much more larger amounts compared to iron. Think of the largest whale compared to a small compact car and that will give you an idea of the ratio.

If you can find a good, quality, slow release nitrogen product that will last 5-6 months then put that down on your lawn 2-3 times a year. Products like Osmocote or Nutricote are very slow to release Nitrogen. You will need to put these sources of Nitrogen on your lawn in heavy amounts in order to get enough Nitrogen or “N” to last. The product may claim 6 months, but generally this is based on year round 70F temperatures so here in Florida it may last 3-4 months.

If you cannot find a product like Osmocote or Nutricote then a traditional fertilizer blend with at least 75% slow release Nitrogen is your second best option. You can generally find these at specialty ag or landscape supply stores. You can expect these products to slowly release N for about 2-3 months, but only in small amounts.

A slow release form of Nitrogen will not give you an immediate “pop” of green. But that is fine. It is much less likely to leach N into the water. The idea is to slowly release N so the turf can use what it needs when available rather than dumping high amounts of N that is leached through the soil and into the water in sandy soil.

The other parts of fertilizer will be addressed at another time.

Fertilizer application rate

Generally speaking, if you have St Augustine grass, you should apply 1 pound of Nitrogen per 1000 square feet per application (granular). How do you do that? It involves some simple math. Lets take a regular bag of fertilizer like 15-0-15. The first number represents the percentage of Nitrogen in the bag. So a 15-0-15 blend will have 15% Nitrogen. Then you just need to divide 100 by 15 to get the number of pounds of N you want per 1000 square feet. 100 divided by 15 = 6.67. Therefore you need 6.67# of 15-0-15 fertilizer to get 1# of Nitrogen per 1000 square feet.

Grab your properly calibrated spreader and apply the 15-0-15. It is recommended that St Augustine get 4-6# of Nitrogen per 1000 square feet per year. Using this formula and applying at this rate should give you green. It may not be the darkest green, but it will be green. If you struggle with the math, a simple thing to remember is that you can divide the first number of the fertilizer bag label by 2 to get the approximate square footage of coverage. For example, a bag of 15-0-15 should cover about 7500 square feet. 15 divided by 2 = 7.5 x 1000 = 7500. My lawn is about 4000 square feet so one bag will allow me to apply the proper amount 2x.

Its not easy being green, but it is not that complicated either. Get a bag of quality fertilizer, calibrate your spreader to achieve 1# of Nitrogen per 1000, and apply the fertilizer 4-6 times per year. Do this only after you have your irrigation system working properly. An alternative is to hire me to do this for you.