Why Fertilizer Particle Size Matters

What “SGN” Means, and Why It’s Important For Your Turf

There’s a lot of information on a bag of LebanonTurf fertilizers, including extensive ingredients and instructions. In particular, there’s one acronym that may be unfamiliar to some users: SGN. It stands for “size guide number”, and as our own Chris Gray sums it up, “the higher the number, the bigger the particle.”

That’s simple enough to understand, but it begs the question: why does it matter to you and your turf? Let’s look at some variables and determine how smaller and larger particles play a role.

Height of Grass

If you’re tightly mowing at a low height—like on a putting green—small particles are crucial. There isn’t a lot of room on a putting green or grass tennis court for the particles to work their way down into the canopy of the turf and to the soil, so the smaller the particle, the better the performance. It’s also much easier to water in the fertilizer after you apply it.

If you’re mowing at a taller height—like a golf course rough or a typical residential lawn, larger particles make more sense since they have more room to get down into the turf.

Gray puts it simply, “The higher the grass height is, the larger the particle you can use.”

Amount of Activity

If you’re managing a golf course or a sports field, the playing schedule can also dictate the size of particle you should use. If you apply fertilizers with larger particles before, say, a soccer match, the particles may not have time to fully embed themselves in the turf. That can lead to clumps of fertilizer on cleats or on the soccer ball itself.

The same goes for golf courses, especially on key playing surfaces like greens. Medium-to-large particles applied right before an important tournament can cause playability issues. In these cases, if your turf has heavy activity in its future, smaller particles are best.

Even Distribution of Fertilizer

Consistency is key when fertilizing turf, especially when your professional reputation depends on it. That means when it comes to applying fertilizer, you need uniform coverage. Gray explains, “The smaller you get in particle sizes, the better you get in particle displacement. So as you’re putting it down, you’re going to cover an area better with smaller particles than you are with bigger particles.

Herbicide combination products, like many of LebanonTurf’s ProScape fertilizers, also benefit from smaller particles because you get better distribution. The smaller particles tend to stay on the leaf of the blade, so they can more directly release the herbicide that kills weeds.

Cost of Product

Most of the “benefits” so far lean in favor of smaller particles (depending on the application), but those benefits do come with a cost. Since fertilizers with smaller particles are more difficult and expensive to manufacture, they’re naturally more expensive for the end user.

So how do you decide?

“It really depends on what your budget is and what your maintenance goals are,” says Gray. If you have a tighter budget, not a lot of traffic, or less of a need for immaculate consistency and playability, larger particles can work very well on your turf. If you need that perfect performance and laser consistency, smaller particle fertilizer is the way to go.

When you’re buying the product in stores, you can often tell the particle size by feeling the product through the bag. However, if you’re working with a LebanonTurf sales rep, all you have to do is mention your need for a particular range of SGN, and they’ll help you get the right product.


For more information about LebanonTurf, our products or how to improve the quality of your turf, visit our website.