Marathon
Marathon Starter Fertilizer 15-15-15
Best balanced fertilizer for establishing new grass and strengthening root systems.
Give your new lawn the best possible start with Marathon Starter Fertilizer 15-15-15. This granular formula is specifically designed to promote rapid root growth and establishment, ensuring your turf gets the vital support it needs during its critical initial weeks. Ideal for application before seeding or sodding, or as a nourishing top dressing for existing lawns, it helps grass establish faster and stronger. One 18 lb bag covers up to 5,000 square feet, making it an efficient choice for spring or fall lawn care.
$29.99
More Starter Fertilizer Options
Owner Satisfaction
4.6
/ 5
Category Rank
1941
/ 4449
#1941 in Fertilizers
Price vs Category Average
-51%
Below average
NPK Ratio
151515
/ --
Who it's for
- Gardeners seeking a simple, all-in-one nutrient solution
- Landscapers performing seasonal overseeding or spring maintenance
- Homeowners establishing new sod or seeding a fresh lawn
Who should skip it
- Data-driven gardeners who prefer precise, soil-test-based fertilization
- Residents living in areas with strict phosphorus runoff regulations
- Beginners worried about burning delicate, young grass seedlings
Performance breakdown
Root Development
Balanced nutrient profile provides the essential foundation for rapid turf establishment.
Application Versatility
Works effectively for new seeding, sodding, or revitalizing existing lawn patches.
Nutrient Balance
The 15-15-15 ratio offers a reliable, all-purpose boost for young grass.
Coverage Efficiency
Eighteen pounds provides ample coverage for standard residential lawn projects.
Ease of Spread
Granular consistency ensures smooth, even distribution through standard broadcast spreaders.
Seasonal Reliability
Dependable performance during the critical spring and fall growing windows.
Key Specs
NPK Ratio
15-15-15
Package Weight
18 lbs
Coverage Area
5,000 sq. ft.
Application Timing
Spring & Fall
Fertilizer Form
Granular
Target Plant Type
Lawn
Water Soluble
False
Organic Certified
False
Features
- Promotes rapid root development for new lawns.
- Ideal for seeding, sodding, or top dressing.
- Balanced 15-15-15 nutrient ratio.
- Covers up to 5,000 sq. ft.
- Suitable for spring and fall applications.
- Granular form for easy application.
What customers say
Customers highly value the Marathon Starter Fertilizer for its exceptional quality and visible results. Reviewers frequently highlight the rapid establishment of new lawns, noting significantly improved root development and vibrant green color shortly after application. The balanced 15 15 15 formulation is consistently cited as highly effective for seeding projects and sod installation. Users feel confident in the product's ability to deliver professional grade performance, making it a reliable choice for achieving a dense, healthy turf.
Know before you buy
While specifically formulated to help new seedlings and sod establish, it can also be used as a nourishing top dressing for existing lawns to support overall health.
The 15-15-15 ratio indicates an equal balance of nitrogen, phosphorus, and potassium. This balanced approach provides the essential nutrients needed for both blade growth and strong root development.
No, this is a granular fertilizer. It is designed to be spread across the soil surface and should be watered in after application to help the nutrients reach the root zone.
A single 18 lb bag provides coverage for up to 5,000 square feet. Be sure to measure your lawn area beforehand to ensure you have enough product for full coverage.
No, Marathon Starter Fertilizer 15-15-15 is a synthetic granular formula and is not certified organic.
This product is best suited for spring and fall applications. These seasons provide the ideal temperature and moisture conditions for new grass to establish its root system effectively.
Still have a question?
Ask Hayley anything about this product before you decide.