Turfgrass fertilization is one of the most important cultural practices needed to maintain a healthy, dense stand of turf. Understanding the role each nutrient plays in turfgrass plants can help determine what is needed to maintain the health of the plants and to also eliminate excessive or unnecessary applications of nutrients. Soil tests are important in helping to determine the amount of each nutrient that is needed in the soil. Before beginning a fertilization program, be sure to take soil and tissue tests to determine required nutrients for optimum soil and plant health.  Soil tests should be conducted on a routine basis - every one (for sand-based fields) to three (for native soil fields) years is recommended.

For soil testing services, contact your local Cooperative Extension office or soil testing lab for materials and information necessary for taking soil samples. 

Fertilizer Programs 

Cool Season Turfgrass 

growth cool season 

With active growth occuring in the spring and fall, the best time to fertilize cool season turfgrasses is from March to June and September to December. (This varies with geographic location.) 
March - May: One to two applications may be necessary in the spring. This application assists with greening up the turf, but can be detrimental if there is a late frost. 
June - August: Heavy fertilizer applications in the middle of summer should be avoided due to heat and drought stressing the plants. If fertilization is necessary, spoon feeding throughout the summer months will maintain turfgrass health. 
September: The best time to fertilize is in the late summer. As plants begin actively growing again, fertilization promotes recovery from drought and heat related injury sustained during the summer months. Fertilization at this time also contributes to root and rhizome growth, disease and stress tolerance, and the storage of carbohydrates. 
October - December: Fertilization in the late fall is advantageous because the majority of nutrients are used for root growth. There is not much vertical growth. Late fall fertilization can also be beneficial to early spring green up. 

Warm Season Turfgrass 

growth warm season 

With active growth occuring throughout the summer, the best time to fertilize warm season turfgrasses is from May to September. 
April - May: Early spring fertilization will assist with spring green up. One of the best times to fertilize is late spring because plants are actively growing and storing and manufacturing carbohydrates. 
June - August: Fertilization can continue throughout the summer. 
September: Late summer is also a good time to fertilize because plants are actively growing and storing and manufacturing carbohydrates. 
October - March: If a field has not been overseeded, fertilization should not take place. 

Tips to Get the Most Out of Your Fertilizer 
1. Soil test to determine the nutrients needed by the plants. 
2. Depending on the turfgrass species, apply nitrogen in the amounts needed. 
3. Apply nitrogen in multiple applications throughout the growing season. 
4. Return clippings while mowing. 
5. To avoid leaching, do not overwater. 
6. Use a slow release fertilizer and apply less frequently. 
7. If using a quick release nitrogen source, water it in to avoid foliar burn. 

Additional Fertilizer Resources:

STMA Technical Bulletins (you must be an STMA member to view these resources):
Understanding Soil Tests
Plant and Environmental Responses to the Essential Nutrients
Quick Release Nitrogen
Slow Release Nitrogen
Rotary Spreader Calibration
Drop Spreader Calibration
Boom Sprayer Calibration
Backpack and Hand-held Sprayer Calibration
Compost Applications to Sports Fields

University Resources:

Soil Testing for Turf Areas - University of Nebraska
Fate and Transport of Phosphorus in Turfgrass Ecosystems - University of Nebraska
What's the ideal fertilizer ratio for turfgrass? - University of Nebraska
Simplifying Soil Test Interpretations for Turf Professionals - University of Nebraska

Mid Atlantic:
     Basic Turfgrass Requirements - University of Tennessee
     Developing a Turf Fertilization Plan - University of Tennessee
     Essential Elements - University of Tennessee
     Fertilizers - University of Tennessee
     Liming - University of Tennessee

Building Your Fertility Program - Cornell University
Calibrating Your Fertilizer Spreader - Penn State University
Calculations Used to Determine the Amount of Fertilizer Needed to Treat Turf - Penn State University
How much phosphorus and potassium are really in your fertilizer? -
Penn State University
How to calculate a fertilizer ratio - Penn State University

Liming Turfgrass Areas  - Penn State University
Using Composts to Improve Turf Performance  -
Penn State University
Using Spend Mushroom Substrate (Mushroom Soil) As A Soil Amendment to Improve Turf  - Penn State University

Turfgrass Fertilization: A Basic Guide for Professional Turfgrass Managers  -
Penn State University
Late Fall Fertilization of Athletic Fields  - Penn State University

University of Illinois - Turfgrass Fertilization
Texas A&M University - Turfgrass Fertilization
University of Tennessee - Developing a Turf Fertilization Plan

Kansas State University - A Guide to Turfgrass Nutrient Recommendations
Penn State University - Nitrogen in the Landscape

Virginia Tech - The Importance of pH
University of Massachusetts - Soil pH and Liming

Purdue University - Turf Fertilizer Calculator  

University of Missouri - Calibrating Sprayers and Spreaders for Athletic Fields and Golf Courses 
University of Massachusetts - Drop Spreader Calibration Procedures
University of Massachusetts - Rotary Spreader Calibration Procedures

Fertilizer Sessions Featured at STMA Conferences:
2015 - The Nuts and Bolts of Applied Nutrient Management - Bryan G. Hopkins, Ph.D., James Gish, CSFM, and Jessica Buss
2013 - STMA 121 - Back to Basics: Getting the Most from Your Granular Fertilizers Speakers: Brad Jakubowski, Tom Samples, Ph.D.
2013 - STMA 206 - Fertility Management for Sand-based Systems Speaker: Nick Christians, Ph.D.
2012 - Perceived and Real Environmental Impacts of Phosphorus (also available as a recorded session here)
Speakers: Dr. Gwen Stahnke, Washington State University - Puyallup, Dr. Elizabeth Guertal, Auburn University
2012 - Environmental and Economic Considerations of Nitrogen Fertilization
Speaker: Dr. Elizabeth Guertal, Auburn University
2012 - Deciphering Your Soil Test (also available as a recorded session here)
Speaker: Dr. Elizabeth Guertal, Auburn University
2012 - Comparison of Synthetic and Organic Fertilizers for Sports Fields (available as a recorded session here)
Speaker: Dr. Tony Koski, Colorado State University
2011 - Research You Can Use: Seedbanking, Seeding Rates, and Increased Nitrogen Fertility (also available as a recorded session here)
Andrew Hoiberg 

2011 - Topdressing with Compost, A More Sustainable and Affordable Alternative (also available as a recorded session here)
Speaker: Marcela Munoz
2011 - New Fertilizer Technology (also available as a recorded session here)
Speaker -
Elizabeth Guertal, Ph.D.

Fertility Podcasts
Turfgrass Fertility - Ohio State University
Foliar Fertilization Concepts - Ohio State University
Efficiency of Foliar Fertilization - Ohio State University
Potassium: Importance, Use, and Fate - Ohio State University
Phosphorus: Importance, Use, and Environmental Fate - Ohio State University
Effects of Nitrogen on Wear Tolerance of Athletic Fields - Ohio State University

International Resources