So, fertilizing a lawn in fall is possible, but warm season grasses are best fertilized when they first come out of their dormant period and begin to produce fresh green growth, in other words, in spring. However, in warm southern regions, where there is no natural rest period, aim to fertilize in April.
Don't fertilize when it's winter or early spring
Your lawn needs an extended period to recover from the cold weather. Fertilizing in this season may cause your lawn to become weak and sickly. The ideal temperature to fertilize your lawn is 50-70 degrees Fahrenheit.
For cool-season grasses, that means in spring and/or fall. Warm-season grasses respond best when fertilized in late spring and/or early summer. Ideally, you shouldn't fertilize the lawn until the ground is consistently at least 55 degrees Fahrenheit.
Generally speaking, you should fertilize your lawn at least twice a year to ensure good overall health and keep your grass looking its greenest. But if you fertilize at the wrong time or over-treat your lawn, you could encourage weed growth, or possibly burn the grass.
The best time to fertilize your lawn is when the grass is actively growing, and for cool-season grasses, that's when temperatures are 60 to 70 degrees F. For warm-season grasses, active growth will usually happen when temperatures are between 75 and 85 degrees F.
Mowing and fertilization are essential aspects of lawn care during your grass's growing season, and the time to do both can sometimes overlap. Although it's tempting to mow and fertilize on the same day to save time, it's far better to mow a few days before fertilizing.
We recommend waiting 24 hours after fertilizing to water your lawn, which will give the fertilizer time to settle. After the 24 hours are up, it's important to give it a good soak—not just a quick spritz with your hose—to activate the fertilizer and help the critical nutrients absorb into the soil.
If the lawn is adequately watered and you're still getting yellow, brown, or rust colored grass, it's time to fertilize. #2: Your grass grows very slowly. Depending on the type of grass you have in your lawn, you should expect between half an inch to several inches of growth each week.
You can usually apply most non-liquid granular fertilizers to wet grass, but not saturated ground. If there are ponds or heavy rain, it's best to wait until the ground processes the water before applying any type of fertilizer. If there's light rain, it's okay to spread dry granular fertilizer.
To avoid over-fertilizing, applying a fertilizer every two weeks is not recommended. Fertilizing as often as every two weeks will likely lead to problems such as lawn burn, excessive grass growth, as well as polluted water that can lead to toxic algae growth.
Ideal Time to Fertilize
Applying fertilizer (and water) in the afternoon will cause the moisture in the soil that is preventing the lawn from burning to evaporate as the sun beats down on the lawn. It's also important for grass to dry out slightly before the nighttime temperatures.
The late afternoon or early evening is the best time of day to fertilize your lawn. With that said, you should never fertilize if there is direct hot sunlight on your lawn. This can lead to burning.
Not only is fall fertilizer the most important feeding for the cold season, but it's also essential for a great spring lawn as well. Fertilizing in the fall gives your grass a head start for next spring by causing an earlier spring green-up.
For cool-season grasses, that means in spring and/or fall. Warm-season grasses respond best when fertilized in late spring and/or early summer. Ideally, you shouldn't fertilize the lawn until the ground is consistently at least 55 degrees Fahrenheit.
Warm-Season Grasses
Just as cool-season grasses, they are usually fertilized twice a year, but the timing is slightly different. The first fertilizer application should be about six weeks after the last spring frost when the grass has turned green, and you have already mowed it at least twice.
But those turf roots are still hungry. Fertilize in the fall and you give those roots nutrients to grow nice and deep now, with some leftover for a healthy start — and thicker grass — next spring. Bonus Pro Tip: Always opt for granular lawn fertilizer.
Watering after fertilizing washes the fertilizer off of the grass blades and into the soil, where it can get to work nourishing your lawn. It's also important because if fertilizer sits too long without being watered in, it can burn the grass.
Rain, or watering-in too early, is fine for the grass, but it washes the product off the weed leaves, so the weed killer can't do its job. To be safe, it's best to apply the fertilizer when the weather is sure to be dry for a day or more. Then, simply water-in with sprinklers after 24 hours.
Ideally, you should fertilize your lawn with the right Scotts® Turf Builder® lawn food for your grass type 4 times a year: in early spring, late spring, summer, and fall. Feedings should be spaced 6 to 8 weeks apart. To save you time, you can choose products that conquer all of your lawn issues in one fell swoop.
Depending on the type, fertilizer can last for years in storage. Liquid fertilizers can last upwards of 10 years, and granular fertilizer has no finite expiration date. It isn't just the chemical makeup of these products that affects their longevity – proper storage is key.
The top setting for most mowers gives a cutting height between 3.25 and 4 inches. This is best for your lawn, but at a setting of 4 inches you may sometimes see some “laying-over” of turf blades that some people find undesirable. For this reason, some people prefer to mow at 3 or 3.5 inches.
Fast-release synthetic lawn fertilizers work within 24 to 48 hours after application. Slow-release fertilizers work more slowly, but they are less risky to use. Synthetic slow-release products work in 2 to 5 days, while organic slow-release versions work in 2 to 6 weeks.
Applying fertilizer at the same time you seed your lawn is not a recommended idea.