Best Summer Fertilizers for St Augustine Grass to Promote Healthy Growth 2025
Maintaining a lush, green St Augustine grass lawn during the summer requires the right fertilizer to support growth, resist heat, and manage weeds and pests. Below is a summary table of top-rated summer fertilizers available on Amazon, designed specifically for St Augustine grass and similar Southern lawn types.
| Product | Brand | Features |
|---|---|---|
| Advanced 16-4-8 Balanced NPK Liquid Fertilizer | Simple Lawn Solutions | Complete NPK blend with Seaweed & Fish nutrients; Ready-to-use spray formula for easy application. |
| Fertilome St. Augustine Weed & Feed 15-0-4 | ferti-lome | Pre-emergent and post-emergent weed control combined with fertilizer designed for Southern grasses. |
| Scotts Turf Builder Southern Lawn Fertilizer | Scotts | Formulated for Southern lawns; builds deep grass roots and protects against heat and drought. |
| Scotts Green Max Lawn Food Plus Iron | Scotts | Dual-action fertilizer with iron to enhance greening quickly on any grass type. |
| Scotts Turf Builder SummerGuard Lawn Food with Insect Control | Scotts | Fertilizer combined with insecticide to kill pests and protect lawn from heat stress. |
Advanced 16-4-8 Balanced NPK Liquid Fertilizer
Simple Lawn Solutions offers this complete 16-4-8 NPK blend fertilizer, ideal for St Augustine grass and other types. It includes additional nutrients like seaweed and fish extracts to nourish the lawn naturally. Delivered in a ready-to-use liquid spray, this product allows precise and easy application, promoting greening and growth during spring and summer. This formula provides key macronutrients: nitrogen for lush leaf development, phosphorus to support root establishment, and potassium to enhance drought resilience. The liquid nature ensures faster nutrient absorption compared to granular fertilizers, making it effective for quick lawn recovery and vitality.
Fertilome St. Augustine Weed & Feed 15-0-4
This product combines a 15-0-4 fertilizer mix with pre-emergent and post-emergent herbicides to control weeds prevalent in St Augustine grass lawns. It is specifically formulated for Southern regional grasses such as Centipede and Zoysia, in addition to St Augustine. The fertilizer encourages grass growth while the weed control ingredients eliminate existing weeds and prevent new ones from sprouting. Note that it is not recommended for Bermuda or northern grass varieties, making it a specialized option for Southern lawns requiring integrated weed management during summer.
Scotts Turf Builder Southern Lawn Fertilizer
This Scotts Turf Builder product is tailored for Southern grass varieties like St Augustine, designed to build strong and deep roots that help the lawn endure heat and drought conditions common in summer months. It consists of All-in-One particles that feed the lawn effectively, enhancing its natural defenses and appearance. Application is flexible — suitable for wet or dry lawns during active growth periods. This fertilizer helps maintain thick, durable turf that can withstand harsh Southern weather, improving both health and color retention of grass.
Scotts Green Max Lawn Food Plus Iron
This lawn food combines fertilizer with an iron supplement, delivering a dual-action approach to lawn care. The addition of 5% iron aids in rapid greening, typically noticeable within three days after application. Suitable for any grass type, including St Augustine, this product ensures lush color and nourishment throughout spring to fall. The balanced nutrients support overall growth while iron boosts chlorophyll production, giving the grass a vibrant appearance that resists summer stress factors.
Scotts Turf Builder SummerGuard Lawn Food with Insect Control
This product from Scotts combines lawn fertilizer with an insecticide to protect St Augustine grass from a variety of common summer pests like ants, armyworms, chinch bugs, and ticks. It not only nourishes the grass but also helps to control insect damage that can weaken lawns during hot months. Applying this product to a dry lawn when pest activity appears helps strengthen the turf’s resistance to heat and drought, ensuring a healthier and more pest-resilient lawn throughout summer.
Buying Guide for Summer Fertilizers for St Augustine Grass
1. Nutrient Balance
Choose fertilizers with a proper NPK ratio that supports both leaf growth (nitrogen) and root development (phosphorus and potassium). A balanced formula like 16-4-8 or specialized blends for Southern grasses helps maintain healthy turf under summer stress.
2. Weed and Pest Control
Consider fertilizers that include weed control or insecticides if your lawn suffers from infestations or weed invasion. Products combining fertilization and pest management can save time and ensure comprehensive lawn care.
3. Application Method and Frequency
Liquid fertilizers, like sprays, offer quicker nutrient absorption but may require more frequent application. Granular fertilizers typically provide longer-lasting feeding but can be slower to show results. Choose based on convenience and lawn needs.
4. Grass Type Compatibility
Ensure the product is formulated for St Augustine grass or other Southern grass types. Some fertilizers designed for Northern grasses or Bermuda may not be suitable and could harm your lawn.
5. Seasonal Use and Climate Considerations
Summer fertilizers should help grass withstand heat and potential drought. Look for products with ingredients that promote heat tolerance and moisture retention to keep grass healthy in high temperatures.
6. Additional Nutrients or Supplements
Some fertilizers include supplements like iron to enhance greening or seaweed extracts for natural growth stimulation. These additives may improve visual appeal and boost lawn health beyond basic nutrition.