Emerald Lawn Fertilizer

10-0-20 · 45% Slow-Release · Iron & Micronutrients

Emerald delivers rich green color while helping established lawns build stronger turf and better withstand heat, drought, and everyday stress. Its high-potassium formula provides steady feeding without pushing excessive top growth.

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Keep Your Lawn Greener, Stronger & Ready for Tough Conditions

BUILT TO HANDLE TOUGH CONDITIONSHelp your lawn stay greener and stronger through heat, drought, and everyday wear.

Better Heat & Drought Tolerance

High potassium helps your lawn handle summer heat, dry spells, and stressful growing conditions while maintaining healthier turf.

A Richer, Deeper Green

Added iron and micronutrients help bring out a deeper green color, keeping your lawn looking healthy and vibrant.

Long-Lasting Feeding

With 45% controlled-release nitrogen, your lawn gets a steady supply of nutrients for weeks instead of one quick burst of growth.

Healthy Growth Without Excessive Mowing

The lower-nitrogen, high-potassium formula helps maintain healthy turf without pushing excessive top growth and constant mowing.

Slow-Release Nitrogen

45% XCU

Recommended Turf

Established Cool- & Warm-Season Lawns

Phosphorus

0% — Phosphorus-Free

Iron + Micronutrients

Contains Iron and Micronutrients for darker green color.

Select Your Grass Type.

Application Rate

4–5 lb per 1,000 sq ft

Equipment

Broadcast Spreader

Apply at the Right Time

Every 6-weeks during the growing season.

After Application

Water in after application

Guaranteed Analysis

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Total Nitrogen (N)10.0%

8.0% Urea Nitrogen†

2.0% Ammoniacal Nitrogen

Soluble Potash (K₂O)20.0%

Sulfur (S)3.1%

Iron (Fe)2.0%

Manganese (Mn)0.18%

Zinc (Zn)0.04%

Boron (B)0.07%

Derived From:

Ammonium sulfate, Ferrous sulfate, Ferrous oxide, Ferrous sulfate, Iron oxide, Ulexite, Manganese sulfate, Manganese oxide, Zinc sulfate, Zinc oxide, Muriate of potash, Polymer-coated sulfur-coated urea, Urea

+4.5% Slowly Available Nitrogen from polymer-coated Sulfur-coated urea.

Spreader Settings

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Find the right starting setting for your spreader.

Spreader Manufacturer Spreader Model

Select your spreader to see the setting.

This is a starting point, not a guaranteed setting. Walk steadily at about 3 mph (100 ft in 23 seconds). Test a measured area and adjust until the correct amount is applied.

Spreader settings & calibration guide →

Documents & Labels

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Product Label

Is this lawn fertilizer safe for my lawn?

Emerald’s slow-release nitrogen reduces the risk of fertilizer burn when applied at the recommended rate. Overapplication can still damage the lawn.

How long will it take for the fertilizer to work?

Once your application is applied and watered in, expect 7-14 days to notice a difference. As the nutrients begin to work, you will notice the lawn growing and darkening up in color.

Can I use this on St. Augustine or Centipede lawns?

Yes. Emerald is phosphorus-free and safe for both. For Centipede lawns, alternate with a lower-nitrogen product like NutriGreen 0‑0‑4 to avoid over-fertilization.

Will it stain my concrete or patio?

Fertilizer with iron can stain hard surfaces, so always sweep/blow stray granules off immediately. Do not wash it off with water.

How long does it feed the lawn?

Emerald feeds slowly and steadily for up to 8 weeks thanks to the 45% slow-release nitrogen. We recommend re-applying fertilizer at 6 weeks to allow some overlap.

Customer Reviews

Overall rating: 4.564706 / 5 from 255 reviews.

AI Generated Review Summary

Emerald 10-0-20 Lawn Fertilizer offers a dark green color and healthy lawn with its slow-release nitrogen and potassium. Customers appreciate its coverage and results, though opinions on color and effectiveness vary. It's suitable for various grass types and requires careful application to avoid staining.

Summary topics

Product Results (25%): Based on a significant number of customers, they are very happy with the results of the product.
Lawn Appearance (10%): Customers loved how the lawn looked after using the lawn fertilizer, as well as its ability to cover the lawn.
Lawn Health (22%): A significant number of customers appreciated that the lawn looks great and has never looked better after using this product.
Lawn Coverage (4%): Customers keep praising The Emerald 10-0-20 for its ability to cover the lawn.
Lawn Color (5%): Opinions vary on the color, with some finding it nice and dark, while others did not get the color as promised.

Review topics: [].

Review highlights

"The lawn is a really nice dark green color." — Derek L.
"Grass looks really good will buy again." — Anonymous
"My lawn quickly came back to life lush and green." — Anonymous

Reviews

I've been a loyal Lawn

"I've been a loyal Lawn Synergy fan for a few years, and will continue to be one. Emerald and Almighty fertilizers are exclusively applied to my TTTF lawn as well as two neighbors lawns I treat here in Delaware. Results are A+, deep dark green color makes our other neighbors envious. Next year I will try NutriGreen between fertilizer applications."

— Linda H. (5/5)

Works great! Every lawn can

"Works great! Every lawn can look amazing with the Lawn Synergy plan. You get exactly what you need when you need it. No more guessing and having to go to the store, at an amazing price."

— Glenda P. (5/5)

Lawn looks great. I would

"Lawn looks great. I would recommend Lawn Synergy products for anyone looking for great results."

— Mitchel s. (5/5)

Zoysia loves Emerald

"The product is fantastic for early fall feeding. The picture was taken 6 days after spreading. Thanks"

— Guillermo G. (5/5)

GREAT!

"GREAT!"

— Marilyn B. (5/5)

Lawn looks great! Greened up

"Lawn looks great! Greened up nice. Looks so much more healthier then before."

— karen L. (5/5)

Zoysia lawn repair

"Attached are two photos, one of my front yard last fall after a sub contractor did a jack & bore. The second picture is end of July this year after adding plugs, pulling weeds and adding Lawn Synergy fertilizer per their schedule. I am totally pleased with the results."

— Gerald C. (5/5)

So far, so good! Will

"So far, so good! Will continue to watch over the next year for results"

— Craig A. (5/5)

"Grass looks great"

— John (5/5)

St Augustine fertilizer

"The jury is still out. I see no results yet!"

— David H. (3/5)

Q&A

My lawn is summer stressed and starting to go dormant. It’s also consistently 85 degrees. Can this be applied ?: Fertilizer should not be applied to a stressed lawn. It can still be applied when hot, but apply early in the AM or late in the afternoon avoiding the heat of the day. Water the product in well after applying.
Does the Emerald contain any weed killer qualities? I have some clover, not much but would like to know if I will have to apply weed killer separately?: The 20-0-10 Almighty Fertilizer does not contain weed control. Post emergent weed control products would need to be used separately.
my lawn in the summer gets sun all day long will this work on my lawn?: This is a great fertilizer choice to use of cool season grass types over the summer season.
Does it work on zenith zoysia grass: 10-0-20 is a great product to use on Zoysia sod as a winterizer fertilizer. During the summer growing season, I would recommend using the 20-0-10 Almighty for zoysia grass.
How long before / after mowing should Emerald be applied?: Emerald can be applied right after mowing. If you are planning to apply before mowing, make sure the product is watered in very well first and then mow once the lawn is dry.

Three bags of lawn care products from Lawn Envy, including North Star 20-0-10 fertilizer, displayed on a green grass surface against a dark green background.

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