Maintenance practices such as fertilizing, watering, and mowing improve the lawn’s health and make the grass lusher. Fertilizing is essential to give a lawn the needed nutrients for a healthy and strong root system. However, you only get a healthy lawn if you fertilize at the correct time. Improper fertilizing destroys the grass and makes the ground inhabitable to microorganisms.
While fertilizing is undeniably effective, timing also matters. Fertilizing every two weeks would be overkill. Only the proper fertilizing schedule will give you the lawn you want.
Here I’ll explore the fertilizing requirements of different turfs to know when and how much to feed your lawn to make your grass thrive.
Can I fertilize my lawn every 2 weeks?
It is not advisable to fertilize your lawn every two weeks. Bi-monthly fertilization of your lawn can have the following effects:
- Overfeeding: Overfeeding makes the grass grow robust, making it more susceptible to diseases
- Burning the grass: Excess fertilizers also saturate the soil with salts, thus burning grass foliages
- Increased environmental pollution: Overfertilizing also leads to chemicals leaching to the environment. Excess fertilizer leaks to water tables and contaminates water sources.
- Wasting money on unnecessary fertilizer purchases.
How many times should you fertilize your lawn?
You should fertilize your lawn thrice every year when the grass is actively growing.
The best time to fertilize cool-season grasses like Kentucky bluegrass is early fall but early summer for warm-season ones like Bermudagrass.
Before adding fertilizers to the soil, perform a soil analysis to determine the nutrients in the ground, deficient nutrients, and the soil pH.
The fertilizing schedules depend on soil type, geographical location, lawn health, and turf performance. Also, pay attention to gradual climatic changes to plan your fertilization schedules.
We’ll look at the specific schedules of the different turf grasses.
Note: Ensure you match the grass to the fertilizer ratio. The ratio is denoted as NPK(Nitrogen Phosphorus Potassium)
Kentucky bluegrass requires 2 to 3 lbs of nitrogen fertilizer per 1000 square feet of lawn annually.
Apply 0.75 to 1.00lbs of nitrogen fertilizer per 1000 square feet during the first application in the fall. A slow-release fertilizer is recommended to feed the grass longer. If a soil test showed low phosphorus or potassium levels, add phosphorus and potassium-rich fertilizer.
Reapply 0.75 to 1lb nitrogen per 1000 square in September every year.
Tall fescue grass requires 3 to 4 lbs of nitrogen fertilizer per 1000 square feet annually. Apply 1 lbs of nitrogen fertilizer in September, and if need be, reapply in November. A nitrogen fertilizer with an NPK ratio of 4-1-2 is suitable.
Apply 1 lbs of nitrogen fertilizer from December through February. Beyond March, don’t add nitrogen fertilizer until the next growing season in September.
Other fescues, such as red fescue, need 2 to 3 lbs of nitrogen per 1000 square feet applied annually in April, September, and October.
Perennial and annual Ryegrasses are grown to provide winter color to dormant warm-season grasses in the transition zones. They make a lawn stay green throughout the year.
When the grasses are actively growing, they require once or twice fertilizer application to maintain their green color. Apply 1.5lbs of 16-4-8 or 15-0-15 nitrogen fertilizer per 1000 square feet. In mid-winter, add another 1.5lbs of nitrogen per 1000 square feet of lawn to retain their green color.
Bluegrass requires 3 to 4 lbs of nitrogen fertilizer per 1000 square feet annually. The first application is made in April, the second in September, and the third in October.
However, high-quality bluegrass needs up to 5lbs of nitrogen per year.
Bermudagrass is a warm-season grass that actively grows in summer. It produces dense, thick lawns.
Bermuda grass requires 2 to 4lbs of 16-0-8 NPK nitrogen fertilizer per 1000 square feet in summer. We don’t recommend fertilizing in January through April (spring). The first frost would damage the lawn. But, coastal lawns with bermudagrass can be fertilized in Spring if there’s no frost predicted.
Apply nitrogen to Bermudagrass in May through August( Summer). The first application is in early May when the grass greens up. Add ½ to 1lb of actual nitrogen per 1000 square feet and another ½ to 1 lbs in mid-summer(June to July) when the grass is in peak growth. Add a phosphorus-rich fertilizer if a soil test indicates a low phosphorus level
In late summer, before August, apply ½ to 1 lbs of nitrogen. Add a potassium-rich fertilizer with a 15-0-15 NPK ratio to help the grass withstand diseases and cold in the coming winter months.
Don’t apply nitrogen fertilizer from September through December as the grass is dormant. Meanwhile, add lime to raise low soil pH and potassium-rich fertilizer to increase winter hardiness.
Zoysia grass produces low-growing, dense turf and is grown in the USA’s southern and transition states.
It thrives in summer and needs 2 to 3 lbs of 15-0-15, 15-0-10, or 15-0-5 nitrogen fertilizer annually. No nitrogen fertilizer should be applied in spring (January through April). In early summer (early May), the grass requires ½ to 1lbs of nitrogen per 1000 square feet.
Apply ½ to 1 lbs of actual nitrogen per 1000 square feet in June or July (mid-summer) and another exact measurement in late summer. Potassium-rich fertilizer is suitable to help the grass withstand diseases and cold in the following winter months.
Don’t apply fertilizer to zoysiagrass in winter (September through December). However, potassium can improve the grass’s cold hardiness and diseases.
7. St. Augustinegrass
St Augustine grass thrives in the southern states. It is arguably the best cold-tolerant warm-season grass for a lawn.
St Augustine needs approximately 2 to 4 lbs of nitrogen annually to keep it healthy. It doesn’t need any nitrogen fertilizer In spring (January through April).
St Augustine grass grows actively in summer, which is the period when most fertilizer should be applied. In early summer (early May), after the grass greens, add ½ to 1 lbs of nitrogen per 1000 square feet of the lawn. The second application is expected in mid-summer (June through July) when the grass is at the peak of its growth. If soil tests call for an addition, add lime and sulfur to correct soil pH.
Add another ½ lbs to 1 lb of nitrogen per 1000 square feet in late summer. Potassium-rich fertilizer is recommended to help the grass withstand the cold and diseases in the coming winter month.
Potassium-rich fertilizer is needed in September through December to help the grass withstand cold and diseases in winter.
Overall, warm-season grasses have similar fertilizing schedules.
The table below summarizes the fertilizer needs of the different grasses.
|Grass-type||Total nitrogen needed yearly|
|Kentucky bluegrass||2 to 3 lbs|
|Tall fescue||3 to 4 lbs|
|Red fescue||2 to 3 lbs|
|Bluegrass||3 to 4 lbs|
|Bermudagrass||2 to 4 lbs|
|Zoysiagrass||2 to 3 lbs|
|St. Augustine||2 to 4 lbs|
Should I fertilize my lawn before or after mowing?
Fertilize your lawn after mowing to make the fertilizer penetrate the short grass and contact the soil quickly for absorption. You also give the yard enough time to use the fertilizer instead of disrupting it with mowing immediately after fertilization.
How often is too often to fertilize the lawn?
Reapplying slow-release fertilizers before six or eight weeks elapse while reapplying fast-release fertilizers before four weeks monthly is excessive and unnecessary and can damage your lawn.
If you want to keep feeding your lawn after the first application, reapply slow-release fertilizers after eight weeks and fast release after four weeks.
When should I fertilize a new lawn?
The right time to fertilize a new lawn is six weeks after the seed sprouts. At this time, you want to feed your lawn with the right amounts of nitrogen, phosphorus, and potassium, so it grows green, healthy, and lush.
A starter fertilizer rich in these nutrients is the best fit to grow the roots of the grass vigorously and profoundly to support the healthy development of the lawn.
- Clemson Cooperative University: Tall Fescue Maintenance Calendar.
- University of Missouri: Cool-Season Grasses: Lawn Maintenance Calendar.