Best Winter Fertilizers for St Augustine Grass to Promote Healthy Lawn Growth 2025
Maintaining a vibrant and healthy St Augustine grass lawn during winter requires the right fertilizer to support cold-season growth and weed control. Below is a summary table of the top recommended winter fertilizers for St Augustine grass, each tailored to enhance green color, provide essential nutrients, and manage weeds effectively.
| Product | Brand | Key Features |
|---|---|---|
| Fertilome St. Augustine Weed & Feed 15-0-4 | ferti-lome | Pre- and post-emergent weed control, targeted for St Augustine, Centipede, Zoysia grass |
| Scotts Green Max Lawn Food + Iron | Scotts | Dual-action fertilizer with 5% iron for deep greening within 3 days |
| Lawn Synergy 20-0-10 Fertilizer + Iron | Lawn Synergy | Stabilized nitrogen, 3.5% iron, aids soil microbes for sustained feeding |
| LESCO St. Augustine Grass Weed and Feed | LESCO | Slow-release formula, 17-0-17 NPK, safe for Floratam variety, up to 8 weeks feeding |
| Lawn Synergy 10-0-20 Emerald Lawn Fertilizer | Lawn Synergy | 10% iron, stabilized nitrogen, enhanced nutrient utilization with AMP-XC & bios |
Fertilome St. Augustine Weed & Feed 15-0-4
This product combines both herbicide action and fertilization, effectively controlling pre-emergent and post-emergent weeds while nourishing St Augustine grass. Its 15-0-4 fertilizer mix delivers nitrogen and potassium without phosphorus, promoting healthy turfgrass during winter months. Designed specifically for St Augustine, Centipede, and Zoysia grass types, it should not be used on Bermuda or northern grasses. This targeted formulation helps maintain lawn vigor and enhances weed control, supporting winter lawn health.
Scotts Green Max Lawn Food + Iron for Greener Grass
This dual-action formula features lawn fertilizer combined with 5% iron, promoting rapid greening visible within three days. Suitable for all grass types including St Augustine, it caters well to winter feeding needs by providing essential nutrients and micronutrients for healthy turf color and growth. Easy to apply and designed for spring, summer, or fall usage, its balanced feeding helps St Augustine grass maintain resilience through colder months.
Lawn Synergy 20-0-10 Fertilizer with Iron
Featuring 40% stabilized nitrogen (All-N) that provides extended feeding periods, this winterizer fertilizer is ideal for St Augustine. It contains 3.5% chelated iron which deepens lawn green coloration while supporting soil microbes for enhanced nutrient uptake. Multiple nitrogen sources balance immediate and slow-release nourishment. This promotes sustained growth and winter hardiness for warm-season grasses like St Augustine.
LESCO 50 lb. St. Augustine Grass Weed and Feed
This professional-grade fertilizer offers a 17-0-17 NPK formula with slow-release nitrogen that feeds St Augustine grass up to eight weeks, minimizing frequent applications. Incorporating 30% poly coated sulfur-coated urea enhances nutrient release control. It is safe for the Floratam variety and is most effective when applied on wet turf with subsequent drying. It also aids in weed control, making it a comprehensive winter lawn care choice.
Lawn Synergy 10-0-20 Emerald Lawn Fertilizer
Designed to produce deep green lawns, this fertilizer includes 10% iron and 45% stabilized All-N nitrogen for extended feeding. The addition of AMP-XC and bios enhances nutrient utilization and supports beneficial soil microbes. Specifically effective on St Augustine, as well as Tall Fescue and Zoysia lawns, this formula ensures robust winter growth and improved turf density.
Buying Guide: Choosing the Best Winter Fertilizer for St Augustine Grass
Selecting the right winter fertilizer for your St Augustine lawn involves careful consideration of several factors to ensure optimal turf health and color during the colder months.
Nitrogen Content and Type
Nitrogen is the most crucial nutrient for grass growth. Look for fertilizers with stabilized nitrogen sources, like polymer-coated or sulfur-coated urea, which provide slow, consistent feeding over weeks. A balanced nitrogen ratio helps on-going grass metabolism during dormancy or cooler weather.
Iron Supplementation
Iron enhances the green color intensity of St Augustine grass without promoting excessive leaf growth, making fertilizers with added iron beneficial for winter applications to maintain lawn vibrancy.
Nutrient Ratio (NPK)
St Augustine lawns typically benefit from fertilizers with a higher nitrogen and potassium ratio (N and K) and limited phosphorus (P) during winter. Potassium supports root health and stress tolerance.
Weed Control Integration
Products combining weed control herbicides with fertilization add value, especially during transitional seasons. However, verify if the product is safe for your specific St Augustine variety and check usage restrictions.
Application Timing and Coverage
Proper application timing is important; many fertilizers recommend application when turf is moderately active or during mild winter days. Check coverage area to match your lawn size for appropriate dosing.
Soil Health and Microbial Support
Fertilizers with components supporting soil microbiomes, such as AMP-XC or bios additives, can improve nutrient uptake and overall soil structure, benefiting long-term lawn health.
By weighing nitrogen types, iron content, weed control features, and slow-release properties, homeowners can select the most effective winter fertilizer tailored for their St Augustine grass needs.