Keeping your lawn lush and green during the warmer months is easy. You fertilize it in spring. Perhaps, the second dose with a bit of weed killer, in summer.
But, it’s disheartening to see all that beautiful sod turn brown and crispy, in winter. The question always seems to be can you keep that from happening, and if so, how?
This article will answer these questions and more. I’ll cover why grass turns brown, even in temperate climates, and what you can do to keep your lawn’s root system healthy year-round, including the best winter lawn fertilizer.
Best Winter Fertilizers
Successful tips for maintaining both cool and warm-season lawns are just a quick read away. But, if you just need fast, reliable recommendations for the best winter lawn fertilizer, here are my top two picks. Extensive testing has shown these to work effectively on any type of grass.
Best Controlled Release
The Andersons PGF Complete 16-4-8 Fertilizer
Fortified with iron and other vital micronutrients, these slow-release granules provide complete nutrition and winter protection plus impressive results within 14 days.
Best Fertilizer Spray
Advanced Lawn Food Natural Liquid Fertilizer 16-4-8
A pre-mixed and easy-to-apply contains iron, nitrogen, organic seaweed, and fish emulsion for better color, foliage, and root growth.
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Why Winterize Your Lawn
Shorter days, with fewer hours of sunlight, will slow down grass growth. Just as it will for every other plant and tree, in your garden.
Older grass blades will actually die off during prolonged periods of cold weather. Resulting in lawns browning. This will occur with all grass types, without exception and regardless of your hardiness zone.
Why? In temperate climates, dormancy is a completely natural process for warm-season grass varieties. Lawns need “restorative sleep”, just like we do. And as gardeners, landscapers, and lawn-care professionals know, there’s no stopping nature.
In cold and severe-winter climates, lawns have no choice but to go dormant in order to survive. Especially when they get covered in thick layers of snow.
So, what can you do to make sure your lawn bounces back, in spring? By building up its tolerance against colder temperatures and diminished sunlight.
Providing the appropriate nutrients, in the right ratio (NPK), for your particular lawn and soil type, will reduce winter die-off and ensure that active roots remain healthy until spring.
Choosing Lawn Fertilizers for Winter
The first step in choosing the best winter fertilizer for your lawn is determining what type of grass you have.
- Is it a warm or cool-season type?
Warm-season grasses include Bermuda, Bahia, centipede, St. Augustine, and zoysia. Cold-season varieties include Kentucky bluegrass, perennial ryegrass, fine fescues, and tall fescues.
- When does it grow most robustly?
Cool-season grasses are most active in fall, after an extended period of warm temperatures and increased rainfall. Warm-season varieties grow vigorously, at a steady pace, from mid-spring to early fall.
- What happens to it in winter?
When temperatures remain below 45°F, cool-season grasses go completely dormant. Warm-season types go all but completely dormant, in winter, in order to conserve energy.
The second step is realizing that “winter fertilizing” your lawn is not something you actually do in winter. But rather, in fall.
The third step is to test your soil. This will dictate what nutrients are present and how much. Which will inform the best NPK ratio for your winter fertilizer and prevent burning or further lawn damage.
Winter Fertilizer N-P-K Ratio
Both warm and cool season types of grass utilize nitrogen more than other macronutrients. So, the best NPK for your lawn will naturally have a higher percentage of it. How high will be determined by the results of a quality soil test?
What is an NPK, exactly?
Every lawn fertilizer label displays a three-numbered formula that indicates the product’s proportions of nitrogen, phosphorus, and potassium.
For example, a 16-4-8 NPK has 16% nitrogen (N), 4% phosphorus (P) and 8% potassium (K). Every lawn type requires these three elements for optimal health. Just, perhaps, in different proportions.
In addition to these three vital elements, there will be secondary micronutrients and trace elements that work together, with the NPK, for effective lawn nourishment and winter protection.
Why Potassium Is Important
While nitrogen is the most utilized element, it can’t perform effectively without the aid of other macronutrients.
In a winter fertilizer, potassium content will be higher than in those formulated for spring and summer applications.
Potassium gives your grass the strength and endurance it needs to resist cold temperatures and limited sunlight. In warm climates, this includes fighting off pests and disease while dormant.
During the warmer months, grasses produce food through photosynthesis. Which is fueled by increased exposure to sunlight. In low-light months, potassium helps warm-season grasses make up the difference by boosting photosynthesis productivity.
Controlled Release Lawn Fertilizer
Controlled release options dispense their contents at a slow and steady pace, ensuring that nutrients are always available. There are a number of perks that come with this application method:
- Grass blades grow at a similar rate, giving your lawn a consistent look.
- Roots grow stronger and healthier when they receive and process nutrients at a slower pace.
- A slower pace promotes increased resistance to disease, pests, and environmental stresses.
- Fertilizer burn is far less likely.
- Less risk of soil and water source contamination.
For you, they free up time. Allowing you the chance to enjoy the transition of seasons, without worry. The only caveat is that because these work slower, you may have to apply them a bit earlier.
Lawn Fertilizer Spray
If time is of the essence, then a liquid fertilizer may be the best winter fertilizer for your lawn. Nutrients move quickly, through the soil to the roots, for a more immediate effect.
Some sprays even come pre-mixed with a built-in hose attachment, allowing for even distribution with less risk of over-applying.
Pre-mixed or not, liquid options are often the most economical. All with the added benefit of being absorbed through blades, as well as the roots. This works really well when a quick correction in nutrients needs to be made right before the first really cold night hits.
Liquids are also easily blended with other nutrients, like kelp and fish emulsion, if the one you choose doesn’t include them.
Chelated Iron Supplement
If you see a yellowish haze spreading across your lawn, as it rouses from winter dormancy, this may be due to an iron deficiency. Lawns use iron to make green chlorophyll cells, which are critical to photosynthesis.
Without iron, grass will begin to yellow. This is especially true in newly-sprouted grass seedlings and new sod. Chelated iron is specially formulated to allow for optimum absorption.
Un-chelated iron isn’t of many benefits to lawns because it naturally rusts when exposed to water and oxygen. If rust is allowed to build up over time, it may lead to iron toxicity in the soil.
Adding chelated iron in autumn is far more beneficial because it’s made with a protective barrier against water and oxygen, preventing rust.
Avoiding Fertilizer Burn on Grass
Preventing fertilizer burn on your lawn starts with following the package instructions carefully. This is typically more common with liquid fertilizers than granular ones.
But, if accidental over-application happens, there are some things you can do to avert catastrophe.
Fertilizer burn happens when high concentrations of fertilizer salts draw too much moisture from your lawn’s root system. These salts dry out the roots, causing the plant to yellow, wilt, or die.
To negate any negative effects, water the overapplied area until it’s fully soaked. Repeat this process every day, for one week, to flush out all the excessive mineral salts.
This may result in a bit of yellowing but when relieved of those dehydrating minerals, your lawn will soon bounce back.
Best Lawn Fertilizers for Spring Reviews
To determine the best choices for both cool and warm season types of grass, I’ve conducted some extensive testing. The results of which I’d like to share with you.
These include specific product details and the pros and cons of each to allow you an informed decision. Below, are the five that came out on top, as the best winter fertilizers for lawns. Based on performance, versatility, and ease of use.
Pros
- Works within 14 days of application
- Provides nutrients for up to 8 weeks
- Large coverage area
Cons
- Needs a broadcaster
Fortified with iron and other vital micronutrients, these slow-release granules showed impressive results in sloped areas of my lawn within 14 days and then continued to release nutrients for a further 8 weeks.
This fertilizer is suitable for both cool and warm-season types of grass, but for best results, you’ll need a broadcast spreader if you have a large lawn,
It’s the range of coverage that this fertilizer provides that is a bonus here. A 40-pound bag of these super-fine particle granules can deliver twice the amount of fertilizer per square foot compared to other brands. And in addition, I noticed the difference in the uniformity of the distribution.
How To Use Set up your broadcast spreader the flow lever is switched off and the hopper is filled with the correct amount of product for your lawn size. Set the distribution rate number.
Place the spreader three feet from your lawn’s edge. Dispense fertilizer around the perimeter first and then row-by-row. Overlap each layer of fertilizer by 6-12 inches. Water well after application.
Pros
- Quick and easy to use
- Fast-acting formula
Cons
- Other options might provide a more even coverage
This faster-acting option offers the same high-nitrogen and sufficient phosphorus and potassium support as my top pick and is suitable for all established grass types.
The main difference, however, is that this lawn fertilizer is a liquid feed as opposed to granules and has a different application method. I’ve placed it second on my list because I know that some gardeners prioritize convenience and speed and so a pre-mixed formula in a bottle that features a hose attachment is just the ticket.
I applied this on samples of St. Augustine and perennial ryegrass just two weeks before the first frost. In spring, both samples greened up beautifully, with thicker, healthier roots. These results were well worth the wait.
How To Use Attach the bottle to your garden hose using the twist screw end. Water pressure needs to be at 50% before you flick the switch to release the fertilizer.
For the most effective coverage spray around the perimeter first and then row-by-row until the entire lawn has been treated.
Pros
- High nitrogen to improve greening and growth
- Contains post-emergent weed killer
- Protects against cold weather
Cons
- May cause fertilizer burn if over applied
This winterizing fertilizer, from Scotts, pulls double-duty with an added weed-eliminator, covering a full 50 weed varieties. I got to put this to good use on a fescue lawn where the previous summer had seen large swathes of clover build up.
By applying these slow-releasing granules in September, most of the clover (except a few stubborn patches) had disappeared, allowing the fescue to grow into those spaces for a beautifully consistent appearance.
How To Use Use a broadcast spreader by filling the hopper with weed and feed granules – enough to cover your entire lawn area. Select the required distribution rate.
Place the spreader three feet from the edge of your lawn distributing evenly row-by-row and beginning at the perimeter. Overlap each fertilizer application by 6-12 inches. Water well once you have completed the application.
Pros
- Improves greening and root growth
- Suitable for warm season grasses
- Reduces the amount of browning
Cons
- Should be used as part of a 4-part lawn care program
This “winter survival” slow-release selection is aptly named and perfectly formulated for cold, dry, winter climates with little-to-no snowfall to protect lawns.
The lack of phosphorus prevented forced growth on my test samples during dormancy. While the increased potassium drastically improved photosynthesis processes with limited sunlight. These two, together, resulted in far less seasonal browning and vigorous spring growth.
Johnson and Green have an impressive portfolio and recommend using this fall fertilizer as part of an annual 4-part lawn care program. It’s effective but it can work out expensive.
How to Use Fill up the hopper of your broadcast spreader with the desired amount of granules. Switch to the correct spreader setting.
Starting at the outside edge of your lawn, work inwards and ensure a 6-12 inch overlap. Water well after application.
Pros
- Offers slow-release nutrients for up to 16 weeks
- High nitrogen means less browning over winter
- Protects against winter extremes
Cons
- Excessive use can lead to over-fertilization
This 32-0-10 NPK also eliminates forced winter growth, in cold, dry climates, with the bonus of added iron. This, plus higher nitrogen, increases proper nutrient availability and absorption, for lawns in poor soil.
A much stronger root system, that’s more resistant to winter stresses, results from just one fall application of these controlled-release granules. Lasting for 16 weeks and supporting cold-season grasses during their fall growth spurt. Come spring, you’ll see far less yellowing, improved soil fertility, and more lush, green growth.
How To Use: Fill a Lawn drop broadcast spreader by adding the desired amount of granules to the hopper. Select the required distribution rate.
Place the spreader near the edge of your lawn. Distribute evenly row-by-row and always begin at the perimeter. Overlap each fertilizer application by 6-12 inches. Water well once you have completed the application.
Fertilizing Lawns Over Winter
Once plummeting temperatures reach a certain point, warm and cold season grasses will fall dormant. During this stage of minimized, metabolic processes, they’re not able to efficiently utilize supplemental additives like fertilizers. Applying any, from December 21 to March 21, means wasting fertilizer and risking killing your lawn.
Winterizing your lawn in the fall is considered transitional care. Preparing it, ahead of time, for often-harsh winter weather. While supporting its current needs, as well as those during dormancy.
Winterizing improves:
- Food storage, within the roots, for winter survival
- Photosynthesis processes during periods of limited sunlight
- Prevention of forced growth in cold-dry climates
- Winter browning
- Spring Yellowing
- Root structure
- Resistance to frigid temperatures, pests, and diseases (like snow mold)
Winterizing is not intended to encourage new growth in fall. Cold-season cultivars will naturally experience a surge of growth in early fall, on their own. Forcing this process could result in severe winter damage. Warm-season varieties gradually slow their growth at this time. Forcing fall growth on these would do the same.
When to Apply Fertilizer for Winter
There’s one general rule of thumb for each grass type. For cool-season varieties, it’s best to winterize between Sept 1st and Oct 15th.
The farther north you live, the earlier, within this time frame, you need to do it. The objective is to have one month of relatively nice, growing weather between the application and the first frost.
There isn’t as much of a time urgency with warm-season grasses. Winterizing, just before these go dormant in fall, could actually leave them vulnerable to pests and disease.
Instead, apply a final dose of summer fertilizer in late August or early September. Warm season grasses will utilize this, just as cool season types do, to bolster winter tolerance and encourage robust spring growth.
Regional Climate and Grass Dormancy
So, how do you know exactly when to winterize your particular lawn within these timeframes? What if it gets colder earlier where you live, compared to your cousin who lives just 50 miles away?
Naturally, climate and seasonal temperatures will vary from place to place. For this reason, local temperature is the most effective benchmark to gauge when both cold and warm season grass varieties go dormant.
Cool-season grasses will slow their internal processes and go dormant when days are consistently below 45-55°F. Warm-season grasses will slip into slumber when the temperature drops below 65°F.
How to Apply Lawn Fertilizer
How to apply a lawn winterize will depend on the brand and application method. Liquids, for example, are sold in different forms. Pre-mixed solutions concentrate or dry and water-soluble.
Some will recommend pre-watering your lawn, some won’t. Once prepared, liquids are best applied using a sprayer that attaches to your garden hose.
Granules are a bit trickier as the right amount needs to be pre-measured for the square footage of the space to be fertilized. Once measured, though, granules can be easily and evenly distributed across your lawn using a push spreader or by hand.
Calculating How Much Fertilizer You Need to Apply
Again, instructions will vary between brands. In my top picks above, I’ve included the area coverage for each option.
In general terms, roughly 10lbs of winterizing fertilizer granules should be applied per 1,000 sq ft. A 50lb bag would cover around 5,000 sq ft.
Liquid options will state on the bottle how much space that particular bottle covers and how to calculate it for smaller or larger areas. However, it’s recommended to use 1lb of liquid fertilizer per 1,000 square feet, for a single application (1 gallon = Approx. 11lbs).
How Often to Apply Winter Fertilizer
When it comes to keeping your lawn healthy throughout the year, winterizing is, honestly, the easiest part to figure out.
Spring and summer fertilizer brands often recommend several applications throughout each season, depending on grass type, and there’s always the risk of overdoing it.
Winter fertilizing requires one application and that’s it. The only time a second may be necessary is if your lawn experienced severe drought or heat in summer.
Stressed-out roots and heavy browning might benefit from a second dose. Or, if you’re using a liquid fertilizer with lower NPK percentages.
What do you do with grass at the end of winter?
If you live in the north, you’re probably familiar with how your lawn looks after all that heavy snow has melted. Flat as a pancake with lots of browning.
But, those remaining green bits should give you some hope. As temperatures increase, that green will expand. When the soil temperature—not the air temperature—reaches 55ºF, it’ll be time to start spring fertilizing.
After months of shorter days, warm-region lawns may also see quite a bit of browning. Spring fertilizing can begin when soil temps are in the 60s F.
Verdict: Best Winter Fertilizer
It looks like we have a verdict! The best winter fertilizer for your lawn will rest on the following:
- Is it a warm or cool-season variety?
- When does it go dormant?
- What nutrients are present in your soil when fall comes?
- Do you prefer liquid or granular options?
The answers to these questions will all point to the perfect choice. Will it be my pick for the best-controlled release winterize?
Anderson PGF Complete provides 8 weeks of granular nutrient coverage for both warm and cool season types of grass.
If you prefer a liquid option that does the same, but faster, then Simple Lawn Solutions is for you. Need to revive a lawn growing in nutrient-poor soil? Then, GreenThumb’s nitrogen-heavy formula is what you need.
Best Controlled Release
The Andersons PGF Complete 16-4-8 Fertilizer
Fortified with iron and other vital micronutrients, these slow-release granules provide complete nutrition and winter protection plus impressive results within 14 days.
Best Fertilizer Spray
Advanced Lawn Food Natural Liquid Fertilizer 16-4-8
A pre-mixed and easy-to-apply contains iron, nitrogen, organic seaweed, and fish emulsion for better color, foliage, and root growth.
