Ready, set, go. It is time to fertilize. I know you have felt like a bird dog on a point ready to flush, just waiting to get the word to start those spreaders. Now you have the command, so let it rip.
Your grass, shrubs and flowers will be oh so happy.
But first, let’s talk about what we are actually doing when we use fertilizers.
Fertilizing is a fairly simple process, but seems to get convoluted. There are some basics you need to know.
Every bag of fertilizer has three numbers on the front of the packaging. Those numbers are nitrogen, phosphorus and potassium (NPK), which we refer to as primary nutrients. Each of these numbers represents the percentage of those elements by weight that are in the bag.
A 10-pound bag of 20-5-20 would have 2 pounds of both nitrogen and potassium and 0.5 pound of phosphorus.
Nitrogen makes the leaves green and leafy. It is the element that is most responsible for plant growth.
Phosphorus is essential for moving energy in plants. It is usually needed more for helping transporting carbohydrates to flowers and fruit as well as moving that energy into the roots, bulbs or tubers. Phosphorus is needed, but not too much in turf.
Potassium is essential for photosynthesis. Simply put, potassium helps with respiration and water movement. This means it is the most important part for healthy root systems. And healthy roots equate to healthy plants.
What the numbers on a bag of fertilizer tell you
All fertilizers are going to have N, P and K listed on the front. But there is more.
Secondary nutrients are calcium, magnesium and sulfur. Plants need these elements (in smaller doses) for growth for a variety of reasons, but still aren’t considered primary elements. They occur naturally in the soil, but sometimes need supplementing.
Calcium is essential in preventing blossom end rot on tomatoes and peppers. I tell folks often to put out dolomitic lime to increase soil pH. The majority ingredients in dolomitic lime are calcium and magnesium, which will cover most secondary nutrients.
Then we have micronutrients. Boron, copper, iron, manganese, zinc, molybdenum and chlorine are all considered micronutrients and come in smaller doses.
Iron is important in maintenance of chlorophyll and if you have yellowing in your centipede grass, it is likely from an iron deficiency. So, we sometime use 15-0-15 centipede fertilizer with added iron.
How to tell which fertilizer is right for you
Pecans have a special need for zinc, so when you are fertilizing pecans, you would normally buy a 10-10-10 with zinc to help supplement.
I buy 16-4-8 with most secondary and micronutrients. Lesco has a good one and it pretty much does all the things I need it to. I use it on my lawn as well as my shrubs. The nitrogen level is medium to light, so my grass turns green and grows, but it doesn’t act like it is on jet fuel and grows 2 inches a week. I can only mow so much.
The phosphorus levels are small at 4%, but P sticks around in the soil a long time, so we don’t need to continually use higher levels of this primary element.
The potassium levels are a good percentage (8%) for supplementing the K in NPK. Potassium leaches quickly in the soil, so it is good to replenish regularly.
This 16-4-8 regiment has worked well for me, but it doesn’t have to be the go-to for all.
There are some good fertilizers out there if you are more fastidious than I am, so I don’t want to discount some of the products out there that are available. My unscientific, non-researched based, biased opinion on quality of fertilizers is if it cost more, it is probably a better product.
Fertilizers that are blended with coated pellets that are partially slow release and quick release nutrients are fantastic products. You can fertilize less often with quality product, but it does come at a cost. If you like to have an electric deep green Bermuda or zoysia lawn in the middle of summer and enjoy mowing two times a week in the hot July summers, add that higher nitrogen product to your lawn in the middle of June. It will look great, but you will be mowing a lot.
Fertilizing makes a big difference in the overall health of the plants. It can turn a stagnant, dull yard into a shiny and lively landscape.
This article originally appeared on Augusta Chronicle: Numbers on a fertilizer bag indicate which type is best for your lawn
