Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
You need a nitrogen boost for your lawn or garden, but the numbers on the bag look like a secret code. The first number in an N-P-K ratio (that is Nitrogen-Phosphorus-Potassium) tells you exactly how much green-growth power is inside — but picking the right one means choosing between a gentle organic meal and a potent synthetic blast. This guide lines up the top performers, from a 46-0-0 urea that can turn corn stalks as thick as your arm to an organic 12-0-0 blood meal that greens up leaves within weeks, so you can match the right nitrogen punch to your specific plants, your schedule, and your philosophy.
I’m Rikta — the founder and writer behind Lawn Gear Lab. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Whether you are feeding a vegetable patch, a thin lawn, or a high-yield corn row, the perfect high n fertilizer is the one that matches your crop, your soil, and your tolerance for frequent mowing.
Our Picks at a Glance
How To Choose The Best High N Fertilizer
Picking a nitrogen fertilizer depends on three things: how fast you want results, what you are growing, and whether you prefer organic or synthetic inputs. A high first number in the N-P-K ratio means more leaf and stem growth, but too much can burn roots or produce all leaf and no fruit.
Know Your N-P-K and Your Goal
The first number is the percentage of nitrogen by weight. A 46-0-0 urea is pure nitrogen with nothing else — it pushes rapid green growth but demands careful measuring. A 12-0-0 blood meal is gentler and adds organic matter to the soil. If you want thick grass or huge leafy greens, go for a higher first number. If you are growing tomatoes or peppers, too much nitrogen means lots of foliage but fewer fruits.
Quick Release vs Slow Release
Quick-release nitrogen, like urea or ammonium sulfate, works within days and gives immediate color change. Slow-release formulas, like polymer-coated urea or organic blood meal, feed steadily over weeks. Quick release needs more frequent application; slow release is safer against burn and lasts longer per bag.
Form Matters: Granular vs Liquid
Granular fertilizers (dry pellets) work with a broadcast spreader and release when watered in. Liquid fertilizers, like the PetraTools 28-0-0, are mixed with water and sprayed on — they are absorbed through the leaves and roots faster, so you see results sooner, but they require more frequent reapplication. Granules are better for large lawns; liquid is ideal for spot treatments and small beds.
Quick Comparison
| Model | Best For | N-P-K Ratio | Weight | Coverage | Amazon |
|---|---|---|---|---|---|
| Down To Earth Blood Meal★ Best Overall | Organic Gardening | 12-0-0 | 4 lb | Depends on use | Amazon |
| The Grow Co Ammonium SulfateSoil Acidifier | Soil Acidification | 21-0-0 | 5 lb | 100 sq ft | Amazon |
| The Grow Co Urea 46-0-0Maximum Nitrogen | Rapid Green-Up | 46-0-0 | 5 lb | Half | Amazon |
| The Dirty Gardener Urea | Lawn & Corn | 46-0-0 | 5 lb | Medium | Amazon |
| Pennington Full Season | low-maintenance Lawns | 32-0-5 | 11.2 lb | 4,000 sq ft | Amazon |
| PetraTools Liquid 28-0-0 | Fast Liquid Feed | 28-0-0 | 2 lb | Up to 12,800 sq ft | Amazon |
| GreenView Fairway Formula | Large Lawns | 30-0-12 | 33 lb | 10,000 sq ft | Amazon |
| Supply Solutions Urea | Bulk Value | 46-0-0 | 40 lb | Turf: 1/5lb per 1,000 sq ft | Amazon |
| Yard Mastery Flagship | All-Season Lawn Care | 24-0-6 | 45 lb | 15,000 sq ft | Amazon |
In‑Depth Reviews
1. Down To Earth All Natural Fertilizers Organic Blood Meal – 12-0-0, 4 lb
Our pick — over 4.5★ from 600+ verified ratings; the strongest balance of quality and price.
The organic powerhouse that greens leafy vegetables within weeks
This blood meal delivers a 12-0-0 ratio (versus the 46-0-0 urea fertilizers in this list), meaning it is a gentler, organic nitrogen source that improves soil fertility while it feeds. The granules are easy to sprinkle around vegetables, herbs, flowers, and lawns, and because it is OMRI (Organic Materials Review Institute) certified, it fits perfectly into an organic gardening program. The 4-pound bag provides plenty of coverage for a mid-sized vegetable garden or a series of outdoor containers.
Buyers report that plants “respond instantly” — one grower noted that vegetative growth was vigorous right after adding this blood meal. The main thing to understand is the honest trade-off: it has a strong initial smell (that is the blood meal odor), and it can attract animals like raccoons and squirrels if not worked into the soil. Over-application also risks nitrogen burn, just like any concentrated nitrogen source. But for organic gardeners who want a quick-acting nitrogen boost without synthetic chemicals, this is the crowd favorite.
What wins people over
- Effectiveness is the most-praised feature — owners consistently see quick greening and vigorous leaf growth
- OMRI certification means it meets strict organic standards for use in organic gardening and farming
- Versatile across vegetables, shrubs, flowers, and lawns — one bag handles most garden needs
The honest trade-offs
- Strong initial smell that fades after watering in
- Can attract raccoons, squirrels, and other animals if left on the soil surface
- Size of the bag gets mixed reactions — some owners find the 4-pound quantity smaller than expected
Best for: Organic gardeners, vegetable growers, and anyone who wants a natural nitrogen source that also adds organic matter to the soil.
Think twice if: You need the absolute highest nitrogen concentration for a large lawn — the 12-0-0 ratio is mild compared to urea options.
2. Ammonium Sulfate High Nitrogen Fertilizer for Plants Rapid Growth, 5lb — The Grow Co 21-0-0
A dual-action fertilizer that feeds while lowering pH for acid-loving plants
This formula packs a 21-0-0 NPK with 24% sulfur, making it a unique high N fertilizer that does two jobs at once. It provides a strong nitrogen punch for deep green growth while also acidifying the soil — a critical feature for blueberries, hydrangeas, azaleas, and any plants that thrive in acidic conditions. The 5-pound bag covers roughly 100 square feet, and the granules dissolve easily in water, so you can apply it through a hose-end sprayer or broadcast it dry.
The owners who have used it on lawns report that earthworm mud piles disappeared after the pH adjustment, and the grass grew “thick and lush.” The review pages are full of stories like one grower whose “peppers and tomatoes were struggling” until this fertilizer turned them “bright green and growing amazing within days.” The main thing to be careful with is over-application — the highly soluble formula can burn if you use too much, and the sulfur smell is noticeable during application. But for anyone fighting alkaline soil or growing acid-lovers, this pick solves two problems with one bag.
Two-in-one value: The pH reduction feature is the second most-praised aspect after overall effectiveness — owners love that it corrects both nitrogen deficiency and alkaline soil in one pass.
Reach for this if: You grow acid-loving plants (blueberries, hydrangeas, azaleas) or have alkaline soil that needs lowering.
Look elsewhere if: Your soil is already acidic or you prefer a purely organic, non-synthetic nitrogen source.
3. 5 lb. Urea Fertilizer 46-0-0, High Nitrogen Fertilizer for Plants — The Grow Co
The highest nitrogen concentration available — makes corn stalks as thick as an arm
At 46-0-0, this is the most concentrated nitrogen source on the market, meaning you use far less product to achieve the same green-up effect. A 5-pound bag of this urea is 46-0-0, while the 12-0-0 blood meal is 12-0-0 — a massive difference in efficiency. It is derived from premium urea and dissolves quickly in water, giving plants an immediate nitrogen boost that shows visible results within days. The suggested rate for established turf is just 1/2 pound per 1,000 square feet, which is remarkably little.
One corn grower sums it up plainly: “I put this on my sweet corn at 6 inches tall and 12 inches tall. I have never had such big beautiful corn.” Another owner said it “boosted my tomato and squash growth this season.” The quality and effectiveness are the most-praised aspects, and owners find it very easy to apply. The catch is that high-concentration urea demands precise measuring — too much and you risk burning roots or creating excessive leaf growth at the expense of fruit. It also needs adequate water to prevent soil dehydration, as noted in the product data.
Why it stands out
- 46% nitrogen is the highest concentration available — one bag goes further than any other option here
- Highly soluble and quickly absorbed, giving plants instant nourishment
- Works across grass, vegetables, fruits, and flowers — versatile for the whole property
What to watch
- Precise measuring is critical — over-application causes nitrogen burn and excessive foliage
- Tends to dehydrate the soil if not watered in adequately after application
- Not organic — synthetic urea does not build soil organic matter
Grab this for: Corn, grass, and any crop where you want maximum growth speed and the highest nitrogen efficiency per pound.
skip it if: You prefer organic inputs or are not confident about measuring tiny application rates precisely.
4. Nitrogen Fertilizer Urea 46-0-0, 5 Pounds — The Dirty Gardener
A straightforward, no-frills urea that owners praise for transforming thin lawns
This is pure prilled urea with the same 46-0-0 ratio as The Grow Co version above, and it comes in a 5-pound bag of dry granules that spread well with most broadcast spreaders. The “prilled” form means each tiny pellet is uniform, so you get even coverage without clumps. The target species listed is corn, but owners use it everywhere — lawns, gardens, and poor soil. The effectiveness is the most-praised aspect, followed closely by quality, and owners also highlight value for money, calling it a cheaper alternative to store-bought options.
The review data is dominated by lawn stories: one owner applies it “weekly in the spring and fall on the lowest spreader setting” and reports “an amazingly green thick lawn.” Another mentions they “look better than the neighbors.” The honest caveat is that uneven distribution causes patchy growth and burn spots, so a good spreader and consistent walking speed are essential. This is not a beginner-friendly “set and forget” product — it demands attention during application — but for the price-conscious gardener who already has a spreader, it is a proven performer.
The collective verdict: Effectiveness (34 mentions) and Quality (27) are the top two aspects by a wide margin — owners consistently agree this product delivers on its promise when applied correctly.
Best suited for: Lawn owners who already own a broadcast spreader and want the highest nitrogen concentration at a competitive per-pound cost.
Not for: First-time fertilizer users who need a forgiving product — uneven application will show as stripes of burn and patchy growth.
5. Pennington Full Season Lawn Fertilizer 32-0-5 4M 11.2lb
One application that feeds your lawn for four months with slow-release technology
Pennington’s Full Season fertilizer offers a 32-0-5 ratio with polymer-coated urea that releases nitrogen slowly over up to 4 months. It also contains 5% iron for deep greening and natural beneficial microorganisms that revitalize soil biology. The 11.2-pound bag covers 4,000 square feet, making it a mid-range option for homeowners who want a single application to last the growing season. The slow-release mechanism means no surge of growth followed by a crash — your lawn gets a steady, consistent feed.
One Bermuda grass owner reports their lawn “looks like a golf course after this application,” with a beautiful dark green color and filled-in bare spots. Another owner notes they appreciate the slow-release iron because it reduces reapplication frequency. The main drawback reported is coverage — a few owners found the 11.2-pound bag covers closer to 2,000–2,500 square feet in practice, not the advertised 4,000. That is a significant discrepancy, so plan for a tighter coverage than the label suggests if you have a larger lawn. Appearance and grass growth also receive mixed feedback, meaning results can vary depending on your specific lawn conditions.
What owners love
- Slow-release polymer coating feeds up to 4 months — low-maintenance for the season
- 5% iron content creates deep, dark green color that neighbors notice
- Natural beneficial microorganisms improve soil health beyond just feeding the grass
What to be realistic about
- Actual coverage is less than advertised — expect 2,000–2,500 sq ft from an 11.2 lb bag
- Growth results vary between lawns; some owners saw no improvement
- Not available in Hawaii and South Dakota per the manufacturer
Ideal for: Homeowners who hate reapplying fertilizer every month and want a single feed for the whole season.
Not ideal if: You need precise coverage for a large lawn, or you prefer to control timing and rate with weekly applications.
6. Petramax Liquid Nitrogen Fertilizer 28-0-0 NPK – 32 Oz
A liquid nitrogen formula that shows visible greening in days, not weeks
PetraTools offers a 28-0-0 liquid nitrogen fertilizer with a unique dual-release technology — 70% quick-release for rapid green-up and 30% slow-release for ongoing feeding between applications. The 32-ounce bottle treats up to 12,800 square feet for maintenance (at 5 oz per gallon of water) or 6,400 square feet for correcting a nitrogen deficiency (at 10 oz per gallon). This is the only liquid option in this list, meaning it is absorbed through both leaves and roots for faster results than granular products.
The feedback from owners is overwhelmingly about speed: “my lawn has never been so green,” one repeat customer says. Another notes it is “easy mix and spray.” The effectiveness is the most-praised aspect by a huge margin — 65 mentions — and greening comes second with 19. The main point to consider is value for money, which gets mixed reviews: some owners find it worth the price, while others consider it expensive for the quantity. Because it is liquid, you will also need to reapply more frequently than with a slow-release granular, so this is best suited for owners who enjoy regular lawn maintenance rather than a once-and-done approach.
Speed advantage: The 70/30 quick-slow release technology means you see green in 2-3 days, but the slow-release portion stretches the feeding window — a real-world balance that owners appreciate.
Choose this if: You want the fastest possible green-up for a special event or you prefer spraying to spreading granules.
Pass if: You want a low-maintenance, one-application-per-season solution or are budget-sensitive about per-ounce cost.
7. GreenView Fairway Formula Lawn Fertilizer 33 lb. Bag, Covers 10,000 sq. ft. | 30-0-12
A 33-pound bag designed for medium to large lawns and 12 weeks of steady feeding
This is a 30-0-12 NPK formula where 63% of the nitrogen is slow-release, so your lawn gets a gentle, consistent feed for up to 12 weeks without the surge-and-crash pattern of quick-release products. The 33-pound bag covers 10,000 square feet, making it a practical choice for homeowners with a quarter-acre or more. The no-phosphate composition protects waterways, a feature for environmentally conscious lawn care, and the formula includes both immediate and slow-release nutrients for balanced growth.
Owners call this their “go to granular fertilizer now,” noting that “the granules are really small so you get a more even coverage.” The small blue granules help prevent overlap and burn when using a spreader. One Bermuda owner reports it “greened up nicely” and did not burn the lawn. Quality and effectiveness are the most-praised aspects, with grass growth and appearance close behind. The main trade-off is that the 33-pound bag is heavy and requires a sturdy spreader — it is not for small yards or balcony gardens.
Why it works for big lawns
- 63% slow-release nitrogen feeds consistently for 12 weeks — no growth surges
- Small granules provide even coverage and reduce the risk of burn from overlap
- No phosphate formula protects local waterways and is environmentally responsible
The practical trade-offs
- 33 lb bag is heavy and needs a sturdy broadcast spreader
- Overkill for small lawns under 5,000 sq ft — you will have leftover product
- Some owners needed a second treatment for remaining bare spots
Best for: Homeowners with medium to large lawns (5,000-10,000 sq ft) who want a single spring application that lasts the season.
pass on it if: You have a small lawn or prefer to control feeding timing with multiple smaller applications.
8. Supply Solutions Urea 46-0-0 Nitrogen Fertilizer (40 Pounds)
A high-volume 46-0-0 urea that corrected a yellow lawn in three days
This 40-pound bag of pure urea nitrogen (46-0-0) comes from Supply Solutions and targets crops, vegetables, and fruits as well as turf. The 46% urea nitrogen content supports protein synthesis and the production of green color in plants, making it a straightforward high N fertilizer for anyone who needs rapid growth. The included resealable pack is a practical touch for storing the remaining product between uses. Application rates vary by target: turf uses 1/5 pound per 1,000 square feet, while trees and shrubs get 3 cups per 100 square feet.
One owner reported that their “yellow lawn turned to rich green within 3 days after watering,” which captures the speed that 46-0-0 urea delivers. Another says it “works for my corn needs.” Quality and growth are the most-praised aspects, but opinion on value for money is mixed — some owners feel it is cost-effective for the nitrogen concentration, while others find it too expensive for the amount received. The key to avoiding disappointment is understanding that 46-0-0 is pure nitrogen; you will need to supply phosphorus and potassium from other sources for balanced plant health.
The owner consensus: Quality (23 mentions) and Growth (18 mentions) are clear strengths, but value for money splits opinion — read the application rates carefully before buying to gauge whether this bag fits your budget per treatment.
Reach for this if: You need pure nitrogen to correct a deficiency fast, and you already have a separate phosphorus/potassium plan for your garden.
Look elsewhere if: You need a balanced all-in-one fertilizer or are concerned about per-bag cost versus competitors of the same size.
9. Yard Mastery 24-0-6 Flagship Granular Lawn Fertilizer with 3% Iron, Bio-Nite, 45 lb Bag
A premium 24-0-6 slow-release formula that revived a dead lawn in one week
Yard Mastery’s Flagship Fertilizer offers a 24-0-6 NPK formula with 24% slow-release nitrogen, 6% potassium for drought resistance, and 3% iron plus Bio-Nite for deep greening and soil health improvement. The 45-pound bag covers 15,000 square feet, making it the largest-coverage product in this lineup and ideal for serious lawn enthusiasts with extensive turf. The weighted, uniform granules are designed for even distribution through a broadcast spreader, and the slow-release nitrogen reduces the need for frequent applications throughout the season.
The reviews for this product are remarkable: one owner reports it “revived a dead, patchy brown lawn to full deep green in one week,” outperforming ten other methods they had tried over eight years. Another says “a couple of my neighbors even asked which lawn care company I use” after the application. Quality and effectiveness are the most-praised aspects, with greening close behind. The honest catch is that this formula is potent — one owner notes “you’ll be cutting grass twice a month” because the growth stimulation is so strong. It is also a premium-priced product, so budget-conscious buyers should weigh the per-bag cost against the 15,000 sq ft coverage.
The standout features
- 3% iron and Bio-Nite technology produce the deepest green color in this lineup
- 24% slow-release nitrogen feeds consistently, reducing application frequency
- 45 lb bag covers 15,000 sq ft — excellent value per square foot for large lawns
What to plan for
- Stimulates so much growth you may need to mow twice a week during peak season
- Premium price point — significantly more upfront than other options
- Heavy 45 lb bag requires a sturdy spreader and some strength to handle
Ideal for: Lawn perfectionists with large properties (over 10,000 sq ft) who want the best possible color and are willing to mow more often to maintain it.
Not for: Small yards or gardeners on a tight budget who do not need 15,000 sq ft of coverage.
Understanding the Specs
N-P-K Ratio — The First Number
The three numbers on a fertilizer bag represent the percentage of Nitrogen, Phosphorus, and Potassium by weight. The first number — Nitrogen — drives leaf and stem growth, and the green color in plants. A 46-0-0 urea contains 46% nitrogen, meaning it is extremely concentrated and should be applied sparingly. A 12-0-0 blood meal has 12% nitrogen and is much gentler. For lawns and leafy greens, a higher first number is beneficial, but for fruiting plants like tomatoes, too much nitrogen produces lots of leaves and few fruits.
Slow Release vs Quick Release
Quick-release nitrogen (like standard urea or ammonium sulfate) is water-soluble and available to plants immediately — you see a color change in 2-5 days, but it also leaches out of the soil faster and requires more frequent application. Slow-release nitrogen uses a coating (polymer-coated urea) or organic breakdown (blood meal) to release nitrogen over weeks or months. Slow release is safer because it reduces the risk of burning roots and provides a steady feed without growth surges. The trade-off is that you do not get the instant green-up that quick-release provides.
FAQ
What does the 46-0-0 number mean on a bag of urea fertilizer?
Can I use a 46-0-0 high N fertilizer on my vegetable garden?
What is the difference between blood meal 12-0-0 and urea 46-0-0?
How often should I apply high nitrogen fertilizer to my lawn?
Will high nitrogen fertilizer burn my grass or plants?
Can I use ammonium sulfate 21-0-0 to lower soil pH for blueberries?
Is liquid or granular high N fertilizer better for my lawn?
What happens if I use too much nitrogen on my plants?
Can I mix different high N fertilizers together?
Do I need to water the lawn after applying granular high N fertilizer?
Final Thoughts: The Verdict
If you want one dependable pick, the high n fertilizer winner is the Down To Earth Organic Blood Meal 12-0-0 because it combines the fastest path to green foliage, OMRI organic certification, and a gentle release that resists burn while building soil health. If you need to lower alkaline soil pH for acid-loving plants, grab the The Grow Co Ammonium Sulfate 21-0-0 for its dual nitrogen-and-sulfur action. And for maximum nitrogen efficiency and the fastest lawn transformation, the The Grow Co Urea 46-0-0 delivers the highest concentration available at a competitive price per pound — just be precise with your measuring and water it in immediately.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of July 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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