Homeowners often think that a fall fertilization application isn’t necessary because the turf will slow down in growth and go dormant for the winter season. But this isn’t the case at all!
Properly fertilizing your turf in late fall is the secret to having a great lawn in the coming year. This final application feeds the turf until it goes dormant, allowing it to store nutrient reserves for the winter.
Winterizer fertilizer helps the grass in the following ways:
Slow-release nitrogen will feed through the cooler months.
Phosphorus boosts the root system, so it is healthy and robust to go into winter, allowing it to take in available water and nutrients.
Potassium hardens grass from the top of the blade to the roots, helping to protect from freezing temperatures.
How you winterize your lawn varies depending upon which type of grass you have. Since cool-season and warm-season grasses have different growing habits, you prepare them for winter differently.
Cool-season grasses take in large amounts of nutrients in the fall to repair damage incurred over the summer and prepare for the winter. Up to 75% of the annual nitrogen uptake is in the fall. They store these nutrients to break dormancy in the spring.
Warm-season grasses only do not need large doses to prepare for a cold winter. They only need a dose of potassium. High applications of nitrogen trigger the grass to grow vegetatively instead of preparing for dormancy.
Cool-season grass protocol (using a winter lawn fertilizer):
First application in early fall at ½ – ¾ of a pound of nitrogen per 1000 sq. ft.
Second fall application in late October or early November at a pound of nitrogen per 1000 sq. ft.
Warm-season grass protocol:
Apply when the grass growth slows for the fall, but the roots are still active. The grass blades should still be green.
Choose a product high in potassium, such as a 4-3-20 or 0-0-18 (potash.
Up to 1 pound of potassium per 1000 sq. ft.
Regardless if you have warm-season or cool-season grasses, avoid using a spring fertilizer for the fall application. Spring fertilizer has too much nitrogen for warm-season grasses. The nitrogen levels are appropriate for cool-season grass types, but it is typically a quick-release formulation designed for quick green-up of grass as the season starts. You want a fertilizer with slow-release nitrogen to feed your grass as long as possible.
Which Types Of Fertilizer Are Best For Cold Weather
When the weather turns cold grasses nutritional needs change. In the fall, the changes begin as the lawn prepares itself for winter.
Typically, warm weather fertilizers are heavy on nitrogen (the first number on the label), to promote fast growth and strength. Winterizing fertilizers are heavy on potassium to strengthen and harden the roots.
Whereas nitrogen works from the top down, potassium works from the bottom up. Represented by the letter K on fertilizers labels, potassium will increase a cool season grasses tolerance to cold and stress.
Winter fertilizers will have a higher number for potassium on the label (the third number present). Typically applied after the first cold spell, winter fertilizers are most effective in late autumn.
Cool season grasses are well suited to late fall fertilization because cooler weather is a peak growing time for them. Application of potassium will help fortify them for the winter to come.
Winterizing fertilizers are formulated with cool season grasses in mind. Because they do not go dormant early, cool season grasses will need continuing nutrients well into the fall months, commonly their peak growing season.
As the seasons progress and the weather and soil temperatures get cooler, grasses need less nitrogen and more potassium. This is to be kept in mind when choosing a winterizing fertilizer.
Often the most beneficial thing to do to a lawn, winter fertilization is ideal because it helps the turf fortify itself for winter as it continues to grow. If only feeding a lawn once a year, the more balanced winter fertilizer is a superior choice. It promotes a more stable grow cycle than nitrogen heavy fertilizers and is a more balance diet so to speak.
The potassium found in winter fertilizers will help keep the root system strong during the colder months which will in turn allow the grass to recover more quickly come spring.
It should be remembered that winterizing fertilizers are not to be used on warm season grasses the same way. A warm season grass should be encouraged to go dormant during the winter months, applying fertilizer prior to dormancy will prohibit it from occurring and promote growth instead. This leaves the grass awake and more susceptible to the cold and other stresses it will endure during the winter.
For a warm seasons grass the best strategy is allow the grass to go dormant and fertilize in the spring with a nitrogen based fertilizer.
Lawns that are fed regularly throughout the year also do not need to be winterized as heavily as the weather turns.