With the seemingly endless choice of fertilizers on the market today, how can you be sure you’re getting a good one?
Listed below are the characteristics of a good lawn fertilizer:
Particle size and uniformity
The size of the granules should not be too large. The average particle size of most fertilizers is 240 SGN (size guide number).
All the particles should also be uniform. This way they’ll spread evenly across the lawn and your spreader will have an easier go of it. This results in even feeding and a better application for any herbicide you may be using. If you’ve got experience spreading a “cheap” fertilizer, you know exactly why this is so important.
A good slow-release nitrogen source
Nitrogen is very important for a healthy, growing lawn. But your grass may use it up so quickly that you get a lot of growth for a week or two, and then nothing. You may have noticed that you had to mow about every third day after using a cheap fertilizer. That’s because these fertilizers have no slow-release nitrogen whatsoever.
A primary example would be the old 12-12-12 or 19-19-19 that you can buy at the farm store. You should never use these on your lawn if you want to benefit from extended feeding. These fertilizers will release right away and will be done feeding in a few short weeks, maybe even a few days. Plus they don’t spread as far across the lawn so you’ll have to use a lot more product, which will end up costing you more money.
Almost all decent fertilizers have some sort of slow-release nitrogen in the bag, albeit at different percentages. On most fertilizers, you’ll see one of the following two products:
SCU stands for “sulfur coated urea”. It is urea (nitrogen) coated first with sulfur, then a polymer sealant, and finally a conditioner.
It’s sort of like a peanut M&M. It’s urea (nitrogen) with a shell on it. This is a good product, but the coating can be damaged during shipping and handling. Also, it only takes a little heat and moisture to break it down. Therefore, it won’t feed your lawn for a very long time… maybe 6 weeks or so.
XCU is a polymer wax coating that outlasts sulfur coated urea (SCU). This will keep the nitrogen available to the grass plant for a little longer than SCU.
Stabilized nitrogen is the best you can get for your lawn. The more elite fertilizers have moved beyond SCU and XCU. You’ll find stabilized nitrogen with trade names such as UMAXX®, UFLEXX®, and REGAIN®. These products keep the nitrogen in the stable ammonium form and in the soil for more efficient use by your lawn. As a side benefit, they also reduce the leaching of nitrates that can contaminate groundwater.
UMAXX provides quick green-up for your lawn but continues to give it that nice green color for up to 12 weeks. It will perform well across many different soil conditions. There is very little nutrient leaching, runoff, or volatilization. In other words, it’s a good product for the environment.
UFLEXX is similar to UMAXX. It provides quick green-up for your lawn but will only last about 8 weeks. This is the cheaper option.
An Appropriate Fertilizer Ratio
The NPK (nitrogen, phosphorus, potash – the three numbers on the fertilizer bag) fertilizer ratio for turf grass is 4-1-2.
4 pounds of actual nitrogen per 1000 square feet of established lawn per season is required.
Nitrogen is the most important nutrient for lawns. Controlling nitrogen release reduces stress to grass plants, increases green color, and keeps nitrogen in the root zone longer. Timely applications provide the optimum green color.
Phosphorus aids in seed germination and turf recovery. A seed starter fertilizer analysis contains higher levels of phosphorus to get your lawn off to a great start. In an effort to keep the lakes and streams cleaner, most companies have removed the phosphorus from their fertilizers, except in their seed starter product.
Potash builds stronger roots for healthier plants and better winterization of grass plants.
As great as N, P, & K are, you should also look for a fertilizer that has a micronutrient package. Micronutrients are actually essential for plants as well as soil microbes. They make both the plant and the soil healthier, giving you greater results.
One other critical component
Soils are typically sulfur deficient. Sulfur is important for several reasons: it improves nitrogen utilization, it helps protect plants from disease, and it helps increase soil humus – with the result that your soil will hold water better. If the fertilizer you’re applying has “ammonium sulfate” in it, that’s the stuff you’re looking for. You can actually buy ammonium sulfate by itself, but often it comes as part of the components in a complete bag of lawn fertilizer.
What’s it all mean for you?
If you apply a quality fertilizer, you may have a bit more cost (per bag) in the product. However, you will also receive several benefits:
- You won’t have to mow excessive top growth.
- You will mow less often.
- Your grass will stay greener and healthier longer.
- You will get higher coverage out of the bag.
In the long run, you will have a better lawn, less labor, and less expense by buying a premium lawn fertilizer.