Fertilizers play a huge role in a yard’s growth and growth speed. As the technologies nowadays are more and more improved, the realm of fertilizers is categorized better and more diverse. If knowing the right one to feed your lawn, it will thrive happily than ever.
The guide below will show you how to choose the best nitrogen fertilizers for lawns, in addition to the four top picks suggested by many lawn experts as well as our tester team.
Don’t overlook it!
Here are the best nitrogen fertilizers for lawn you can buy in 2025:
- Best Overall: Worm Castings Organic Fertilizer
- Best For The Deep Green Color: American Hydro Systems 2655 GrassSoGreen Fertilizer
- Best For A Lush Lawn: Milorganite 0636 Organic Nitrogen Fertilizer
- Best For Fast Growth: Rapid Green & Growth Liquid Fertilizer
| Best Nitrogen Fertilizer For Lawns: Top 4 Picks | ||
|---|---|---|
Best Overall | Worm Castings Organic Fertilizer | Read Our Review |
Best For The Deep Green Color | American Hydro Systems 2655 GrassSoGreen Fertilizer | Read Our Review |
Best For A Lush Lawn | Milorganite 0636 Organic Nitrogen Fertilizer | Read Our Review |
Best For Fast Growth | Rapid Green & Growth Liquid Fertilizer | Read Our Review |
Best Overall: Worm Castings Organic Fertilizer
- Perfect for both indoors and out – odor-free
- Safe to the soil, human’s and pet’s health – non-toxic
- Add nutrients to the root zone and improve soil’s quality – 100% organic fertilizer
- Come with little weeds
The Worm Castings Organic Fertilizer is actually a soil amendment that helps get the microbiology going in your dirt. It doesn’t cause harm to the soil like the NPK fertilizer.
It feeds the soil and the root zone to provide nutrients to your plants, and you’ll get the same or better results than those chemical fertilizers. Take note that it should be put into each planting hole and not spread out as compost.
As releasing no unpleasant odors or toxins, it’s perfect for both indoors and out. You can apply it to your flowers, vegetables, houseplants, and more.
Overall, we highly recommend this for every gardener, especially those who are in a tight budget.
| Worm Castings Organic Fertilizer Specifications | |
|---|---|
Size | 15 pounds |
When to Apply | During growing season |
Coverage | 8 lbs per 100 square feet |
Highlight Features | Non-toxic and odor-free Organic fertilizer |
The Worm Castings Organic Fertilizer is a lot like the chemical fertilizer in terms of odor-free and ease of use, only better because it contains no toxins and helps improve the soil’s quality, not harming it. For that reason, it’s worth our Best Buy Award.
Best For The Deep Green Color: American Hydro Systems 2655 GrassSoGreen Fertilizer
- Economic – each one-gallon of the fertilizer is enough for 4000sq.ft. area for a month
- Boosts nutrients to the grass without burning it - 30% Bio Builder
- Easy to use – created to use in the Green Feeder
- A bit pricey
- Wish the bottle material was sturdier
For souped-up healthy soil building, the American Hydro Systems 2655 GrassSoGreen Fertilizer is added a “secret weapon”, called “Bio Builder” – 30%.
If you have no idea of what it is, this substance is an all-natural mix of many organic ingredients and humates, which boosts nutrients to the grass without burning it. This fertilizer is also known for its ability to replace lost nutrients during the mowing.
The final result is a greener, thicker landscape throughout the entire sprinkling season.
Each one-gallon of the American Hydro Systems 2655 is enough to feed 4000 square feet of area per month. You can use it for either warm or cold season grasses.
| American Hydro Systems 2655 GrassSoGreen Fertilizer Specifications | |
|---|---|
Size | 1 gallon |
When to Apply | as you water your lawn |
Coverage | 4,000 sq. ft |
Highlight Features | 4,000 sq. ft. of coverage Contain 30% Bio Builder |
The American Hydro Systems 2655 GrassSoGreen Fertilizer is one of our favorite nitrogen fertilizer for deep green color lawns because it’s effective, non-toxic, and efficient.
Best For A Lush Lawn: Milorganite 0636 Organic Nitrogen Fertilizer
- Not burning the lawn – organic composition
- Energy efficiency - 4% non-staining iron & slow-release formula
- Should not be continuously used for a long time – contain phosphorus
The Milorganite 0636 Organic Nitrogen Fertilizer is the best way to maintain your lush lawn at the lowest energy cost.
It is complete with 4% non-staining iron and a slow-release formula to cut down mowing time and watering needs, keeping your lawn beautifully green without growth. In other words, it gives you the best of both worlds – lush grass and energy efficiency.
Because of its organic composition, you can go heavier if wanting to add some extra top growth with no worry about burning your lawn. Our secret to getting the best results is mixing it with a balanced fertilizer that doesn’t contain a huge amount of potassium and besides, no phosphorus.
By saving tons of time, effort, and money, it is well-loved to use in most golf courses, parks, and large lawns.
| Milorganite 0636 Organic Nitrogen Fertilizer Specifications | |
|---|---|
Size | 32 pounds |
When to Apply | During the growing season |
Coverage | 2,500 square feet |
Highlight Features | Organic composition Reduces the need for watering 4% non-staining iron |
If you’re looking for the best nitrogen fertilizer for lush lawns, we suggest trying the Milorganite 0636.
Best For Fast Growth: Rapid Green & Growth Liquid Fertilizer
- Easy to use – versatile hose-end sprayer attachment
- Help grass grow faster - Including a premium blend of fast & timed-slow release Nitrogen sources
- The bottle material could be higher quality
The Rapid Green & Growth Liquid Fertilizer pleasantly surprised us with its ability to promote super-fast effects on the grass.
Only a couple of days after application, we found a noticeable improvement to our lawn’s appearance. It looked lusher and healthier no matter the weather conditions. That is a big thank you to the inclusion of a premium mixture of fast and timed-slow release Nitrogen sources.
This fertilizer is also very easy to use with the provided sprayer which can fit with any standard garden hose. No mixing required it’s ready to apply right out of the box.
Each bottle of 32 ounces is enough for 4000 square feet of lawn, which is quite efficient.
| Rapid Green & Growth Liquid Fertilizer Specifications | |
|---|---|
Size | 32 ounces |
When to Apply | Spring & Summer |
Coverage | 4,000 sq. ft! |
Highlight Features | EASY-TO-USE HOSE END SPRAYER Including a premium blend of fast & timed-slow release Nitrogen sources |
Rapid Green & Growth Liquid Fertilizer is one of the most effective organic fertilizers that we’ve tested. Its perfect mix of fast and timed-slow release Nitrogen sources is key to boost grass grow much faster.
How To Choose The Best Nitrogen Fertilizers For Lawn?
Types Of Nitrogen Fertilizer
The two major types of nitrogen in fertilizer are CRN (controlled-release nitrogen) and SRN (slow-release nitrogen).
Controlled release nitrogen
- There are polymer coatings or an organic resin which acts as a semi-permeable membrane to encapsulate completely the CRN particles, which is key to delay the nitrogen release process.
- This membrane only allows a certain amount of particles to pass through as well as allow one-way passage of water to “osmosis” or absorb and dissolve the urea inside. Once creating a highly-concentrated urea solution, it will be diffused out of the particle into the soil.
- As you can see, the speed of releasing nitrogen depends mostly on the soil temp and moisture.
- It requires ideal temperature levels as well as the moisture to take place the reaction inside the CRN molecules.
Slow-release nitrogen
- Ammonium nitrate is the only form of nitrogen that grass can absorb and utilize.
- The way this type of nitrogen fertilizer works is feeding another form of nitrogen into the soil and take advantage of the microbial activity to slowly break down the particles and convert them to ammonium nitrogen.
- This substance will be ammonium nitrate later and used by the plants.
- That “another form of nitrogen” is actually long-chain particles made from a chemical combination of an aldehyde and nitrogen source.
- The difference between this and the CRN is what affects its release process. In this case, that is the microbial organism’s molecular breakdown (including growing medium, soil temperature, and moisture).
- Another difference is the period of time for releasing molecules:
- CRN duration of 10-14 weeks
- SRN duration of 12-16 weeks
Types Of Grass
All turfgrass needs a huge amount of nitrogen in fertilizer than other plants but the amount is varied between different grass types.
Below is a quick reference for annual nitrogen needs for some popular types of grass:
- St. Augustine – 2 pounds/3 pounds
- Kentucky Bluegrass – 3 pounds/5 pounds
- Bermuda grass – 3 pounds/4 pounds
- Bentgrass – 4 pounds/5 pounds
- Zoysia grass – 1 pound/2 pounds
Shown as the overall quantity of nitrogen per 1000sq. ft. for low maintenance vs high-quality lawns.
Which Brands Make The Best Nitrogen Fertilizers For Lawn?
Unco Industries
- Unco Industries, Inc. has been in the industry for over 40 years and also the only one that owns the worm growing system that provides all of the basic manufacturing principles.
- The one who has improved this system and made it be a true business is Tom Chapman, who is the current CEO. From that point, we feel very rest assured about the expertise and knowledge of this brand’s team.
American Hydro Systems
- Another worth-considering brand is American Hydro Systems. It has had over 25 years’ experience in producing irrigation products and fertilizers.
- Each product line is the result of a year’s researching, testing, and improving to deliver only the best performance, quality, and satisfaction to their customers.
Milorganite
- This is probably the longest-standing brand on our list. Milorganite, founded in 1926, USA, is a brand dedicated to biosolids fertilizer produced by treating sewage sludge.
- Recycled fertilizer includes phosphorus and nitrogen – the two vital nutrients that most plants need for healthy growth.
LawnStar
- At LawnStar, you’ve got a chance to try new generations of lawn care products using state-of-the-art technology. Their products are budget-friendly, quick-acting, and easy to use, which saves you tons of time and effort.
FAQs
When should you put nitrogen on your lawn?
Two months before the first frost is the general rule to put nitrogen fertilizer on a lawn that already has warm-season turfgrasses. September 15th is the latest for people who are living in the deep South.
How much nitrogen can I put on my lawn?
0.9 pounds per 1000 square feet per application.
Does nitrogen grow grass faster?
Yes, it does.
Nitrogen promotes health turf by boosting the chlorophyll production – an essential chemical to photosynthesis.
Phosphorus encourages grassroots and stems in a short amount of time.
What if it rains after I fertilize my lawn?
Wait until the grass blades are completely dried and start re-touching fertilizer on your lawn.
How long does it take for nitrogen to turn grass green?
15-24 hours in good conditions, based on the Midwest Sod Council.
Conclusion
When it comes to choosing the best nitrogen fertilizer for lawns, the most important feature is almost always the type of grass in your yard. However, depending on your lawn needs and personal preferences, other factors can vary in importance.
Hopefully, this review will assist you in the marketplace of nitrogen fertilizer.
