Fertilizing can be tricky. Timing, formulation and frequency depend on a variety of factors, and getting it wrong can do more harm than good. Since we’re all stuck at home, let’s take a little extra time to learn about the care and feeding of our grass. Our lawns will be happier and more beautiful for it.
When to Fertilize
DON’T FERTILIZE TOO EARLY. The warm spring temperatures make it tempting to get out and work in the yard, but if you have warm season grass that goes dormant in the winter, don’t feed the grass until it fully greens-up. Wait until after April 15 when your lawn will be actively growing and able to absorb the nutrients.
Feeding grass at the wrong time wastes time and money, since dormant roots can’t absorb the nutrients. Also, fertilizing dormant grass feeds the weeds, giving them an opportunity to crowd out your grass.
Worst of all, fertilizing grass that’s just beginning to come out of dormancy boosts growth at a time when there is still potential for a killing frost. A hard spring frost poses much greater threat to a fertilized lawn, causing more severe damage and possibly even killing your grass. Your lawn has a better chance of surviving a late frost if you wait to fertilize until after April 15.
Know Your Grass
Before you fertilize, it’s important to identify what variety of grass is growing in your lawn. Warm season grasses, like Bermuda, zoysia and centipede, should be fertilized mid-April through August, whereas cool season grasses, like tall fescue, should be fed in March and again in October.
Also, fertility requirements differ by grass variety, affecting how much and how often you need to fertilize. Bermuda tends to need more nitrogen than zoysia, for example.
Know Your Soil
If you haven’t already tested your soil now is the time to do it. Your yard’s soil supports your grass with three major nutrients: nitrogen (N), phosphorus (P) and Potassium (K). Fertilizer packages are labeled with numbers that relate to those nutrients in that order, such as 16-4-8 or 10-10-10.
A soil test will tell you if your soil is high or low in these elements, as well as secondary nutrients like calcium and magnesium or micronutrients like manganese and zinc. In general, Georgia soils tend to be lower in potassium than phosphorus, so a 16-4-8 formulation is a safe bet in lieu of recommendations from a soil test.
More is not necessarily better. Improper fertilizing can cause a host of issues. Excess nitrogen leads to thatch accumulation in some varieties, for example. Imbalanced fertilizing can also lead to increased potential for disease or infestation and can even inhibit growth.
If you hire a company to fertilize your lawn, talk to them about their process. It should involve regular soil testing and a plan customized to your grass variety.
More Fertilizing Tips
- Avoid combination weed and feed products. To control weeds, it’s best to apply a pre-emergent herbicide in late winter, when the forsythia blooms, and again in the fall—which are not optimal times to fertilize.
- Use a mulching mower. Leaving mulched clippings on the yard can reduce your lawn’s need for fertilizer by up to half. Mulching mowers break grass clippings into tiny bits that drop to the soil surface where they become food for your lawn.
- Don’t overwater. Excess irrigation, especially of sandy soils, increases fertilizer requirements.
- Don’t fertilize wet grass. The fertilizer may cling to the wet blades and cause the grass to burn.
- Do water-in the fertilizer. Watering the grass after fertilizer application (or fertilizing just before a soaking rain) helps ensure the nutrients get to the grass’ roots.
- Use a broadcast spreader. You’ll get a more even application than if you try to fertilize by hand.