Turf loves slightly acidic soil
Your lawn loves low nitrogen (N), low phosphorus (P), and low potassium (K) fertilizer. It also likes organic fertilizer or urea-based fertilizers, not nitrate-based fertilizers. Why? Well, let’s look at the nature of lawns, especially warm-season grasses like St. Augustine, Bermuda, and Zoysia.
These grasses prefer slightly acidic soil or a 6.0 to 7.0 on the pH scale. When soil becomes too alkaline (chemists call this “base”), all sorts of things start to happen. The grass roots weaken, and each plant becomes more susceptible to disease and infection. And that’s how your lawn speaks to you if you use the wrong fertilizer. So how do you find out what’s the pH of your lawn? It’s simple. Get a soil test done. It’s inexpensive (a basic soil test costs about $15) and reliable.
Almost all, if not all, of the land grant colleges, have soil testing laboratories. All you need to do is print out a form from their website, take a sample of your soil and send it to them. You’ll get a full report back in about two weeks.
If you’re not too familiar with soil science, you may want to check with your county or parish extension agent, who can interpret it for you. It’s a heck of a lot less expensive than having lawn diseases and lawn pests decimate your lawn, and then you have to spend money to repair the damage.
Here are web addresses for each of the state agricultural universities along the Gulf Coast:
Louisiana State University Soil Testing and Plant Analysis Lab
Mississippi State University Soil Testing
Texas A&M Soil, Water, and Forage Testing Lab
Auburn University Soil Testing Laboratory
University of Florida Extension Soil Testing Laboratory
Nitrates vs. Urea vs. Organics
There are several other pieces of information that you may want to consider before you fertilize your lawn. The nitrogen in fertilizers comes in several different forms: 1. Nitrate-based, 2. Urea-Based, and 3. Organic-based. I said before that lawns do not like nitrate-based fertilizers. Nitrate-based fertilizer can help the soil become more alkaline, which is not beneficial to turfgrass. Nitrates also wash out of the soil and into our streams and rivers, harming plants and wildlife.
Urea-based synthetics and organic fertilizers do not have that quality and can help keep the soil at a stable pH level. However, I actively promote organic fertilizer because it is slow release, stays in the ground longer,
Organic fertilizers don’t create a crust on the soil, as do synthesized fertilizers. This lack of “crust” allows water to flow into the grass roots. They also do not leach out as quickly and have a longer life in the soil. Since most synthesized fertilizers have a lot of sodium, which is harmful to the beneficial microbes that live in the ground, organics may be the better choice. However, things like raw manure are also high in salts. Make sure that if you put manure down, it has been thoroughly composted.