The best time to make late fall applications of lawn fertilizer is typically in November or the very beginning of December when the grass stops actively growing or has slowed down to the point of not needing to be mowed.
The November application also provides for early spring green-up without excessive top growth. Simply put: a beautiful green lawn with less mowing. But applications of fertilizer in late winter or early spring are converted directly to top growth. You'll get the same green appearance but it will require more mowing.
When To Fertilizer Your Lawn in the Fall. The best time to apply your last fertilizer application is between August 15 and October 1. Ideally, your last lawn feeding should take place six to eight weeks before the average first frost in your area.
Don't fertilize when it's winter or early spring
The ideal temperature to fertilize your lawn is 50-70 degrees Fahrenheit. Any lower than this, your lawn will struggle to maintain nutrients.
Don't apply winterizer too late—Generally, winter fertilizer should be applied in November or earlier, depending on your climate. Try to avoid applying in early December, as the nutrients within the formula may not take hold in time to protect the grass from the harsh conditions.
A complete fertilizer with a high ratio of both nitrogen and potassium is essential for enhanced rooting, cold hardiness, disease resistance, and wear tolerance. An ideal fall fertilizer blend has a nitrogen to phosphorus to potassium (N:P:K) ratio of 24-4-12 with isobutylidene diurea (IBDU).
A complete fertilizer with a high ratio of both nitrogen (N) and potassium (K) is essential for root growth, winter hardiness and disease resistance. An ideal fall fertilizer blend will have a nitrogen to phosphorous to potassium (N:P:K) ratio of 24-4-12.
Applying fertilizer in the wrong season can cause increased tender new growth that can be damaged, especially if applied in cold weather in late fall or in winter. So it is best to stop fertilizing during dormant seasons. Additionally, in zones that can be in danger of a late freeze, it's best to wait until mid-spring.
Winterizer Fertilizer
Winterizer helps the roots of the grass absorb and store nutrients. The roots continue to grow until the ground eventually freezes. These nutrients are stored and ready to go, so when spring comes around, your lawn hits the ground running.
The good news about rain or snow is that both are very good for your fertilization treatment. Fertilizer needs to reach the root system and it needs to mix with water. The fertilizer breaks down with either rain or snow. Now the fertilizer will begin to feed the root system and green up the lawn.
This means the temperature can't be below freezing, so the task is typically handled sometime in early November in most places in the north. If you live in a warmer area, however, December can be a great time to fertilize your lawn.
Fertilizing in the fall helps plants be hardier when the temperatures drop. We also recommend applying fertilizer in the late fall, toward the end of October or early November. This application will catalyze one last frenzy of root growth and really give your plants some staying power through the cold months.
Although some fertilizers benefit from slightly moist grass, if your lawn is too wet, it will fail to properly absorb the nutrients. This includes both granular and liquid fertilizer products. You should avoid applying foliar fertilizer to wet grass because it could lead to nutrient burn.
Although grass does not stop growing in winter, it grows so slowly when temperatures go below 40 degrees Fahrenheit that mowing your lawn between November and March isn't necessary (scroll down to see the step you must follow if you need to mow your lawn during winter).
Fertilizing a dormant lawn will not harm it. However, the turfgrass may not receive the full benefit of the fertilizer application. If the granular fertilizer remains on the soil surface because of a lack of rain, some of the material may actually volatilize into the air.
Apply Milorganite between mid-October and Thanksgiving but before the ground freezes.
Don't let the term fool you. Winter fertilizers are applied in the fall in preparation for winter weather. A winter fertilizer, aka fall fertilizer (whatever you want to call it, really), is a great way to feed your lawn one last time before you put it to bed for the year.
Best Fertilizer for Cool-Season Turfgrass
Nitrogen is probably all your lawn needs. N-P-K are the letters you'll see on fertilizer labels and they stand for the key nutrients: Nitrogen (N), phosphorus (P), and potassium (K).
For cool season lawns the important macronutrient heading into winter is nitrogen (the first number on your fertilizer label). A little Potassium is good too (the third number). For warm season lawns you want little to no nitrogen and mostly just potassium (the third number).
Ideally, you'll want to mow and rake before fertilizing, so that excess lawn waste is removed and the fertilizer will have an easier time reaching the soil.
During the growing season from spring through fall, your lawn, whether established or newly seeded, will perform best when fed four times, with each feeding applied 2 to 3 months apart.
If a granular fertilizer remains on the soil surface because of a lack of rain, some of the material may actually volatilize into the air. It probably would be best to wait until the weather pattern changes (hopefully soon) and it begins to rain before fertilizing the lawn.
Fertilizer should not be applied to already frozen ground since it will not do any good to the lawn. Worse still, the unabsorbed nitrogen and nutrients will likely leach back into the water system. The best time to apply winterizer is in late fall, about three weeks before the ground is frozen.
November fertilization is one of the most important yearly applications to a bluegrass or tall fescue lawn. An application of a high, quick release nitrogen fertilizer will pay big dividends next spring.
As a general rule, warm-season grasses will need four times per annum feeding. Apply the first dose when you see new growth starting - this should be done around March/April time frame for most areas with mild winters which helps their young leaves grow healthier faster than if they were left untreated all season long.