Best Winter Fertilizer For St Augustine Grass: 10 Options Compared

#1 · Best Overall

1. Espoma Turf-Tone Fall Winterizer

• Weight: 30 lb
• Form: Granules

Best for: St. Augustine Organic Option.

Why it ranks #1: Its stated use explicitly includes St. Augustine; the 8-0-5 formula adds potassium, and the 30-pound bag covers up to 5,000 square feet.

Explicitly listing St. Augustine among its suitable grasses makes Espoma Turf-Tone especially relevant to this roundup. Its natural and organic 8-0-5 formula includes extra potassium, with the product description linking that nutrient to recovery from summer stress and spring green-up for lawns preparing for winter.

Turf-Tone is a granular fall winterizer made with natural and organic ingredients, including feather meal, poultry manure, and potash. The listing says it is for all lawns and specifically names St. Augustine, fescue, bluegrass, rye grass, and zoysia, giving buyers a direct compatibility reference. Apply in fall with a drop or broadcast spreader for even coverage. The product also states that it will not burn lawns or leach out of soil, addressing concerns around application and nutrient retention.

Skip it if you need a stated feeding duration; Green Thumb GT58105 specifies continuous feeding for up to 16 weeks.

A strong match for St. Augustine owners seeking a fall-applied organic granular fertilizer with a named grass-type fit. Use a drop or broadcast spreader for even application, and follow the product’s fall timing.

Listed on Amazon as: Turf-Tone Fall Winterizer 8-0-5 Natural & Organic Lawn Food. Long Lasting Organic Nitrogen & Potassium for a Winter Strong Lawn. 30 lb. Bag Covers up to 5,000 Sq. Ft.

#2 · Broad Grass Use

2. Scotts Turf Builder WinterGuard Fall Lawn Food

• Weight: 8 oz
• Form: Granules

Best for: Scotts Fall Recovery Routine.

Why it ranks #2: Scotts says it can be used on any grass and describes fall feeding to build deep roots, though no nutrient ratio or coverage is supplied.

Fall application on either a wet or dry lawn is the central convenience of Scotts Turf Builder WinterGuard Fall Lawn Food. It targets roots after summer heat, drought, and regular activity, giving homeowners a seasonal feeding step intended to support stronger roots and a better-looking lawn next spring.

The formula is described as building strong, deep roots while supplying nutrients for recovery from summer stress, so it combines fall preparation with post-summer lawn care. Scotts lists use on any grass, making the product applicable beyond one named turf type. Granules can be applied with a Scotts spreader; the supplied directions give settings for Scotts rotary and drop spreaders. Light watering is suggested for fast results, but the product does not require watering in.

Skip it if you need a stated coverage figure before choosing a bag; Green Thumb GT58105 specifies coverage up to 5,000 square feet.

A practical option for homeowners planning a fall feeding after summer stress, including lawns with varied grass types. Check the label for application directions and note that the supplied listing does not state this bag’s coverage area.

Listed on Amazon as: Scotts Turf Builder WinterGuard Fall Lawn Food, 10 lbs.

#3 · Potassium-Rich Formula

3. Jonathan Green Winter Survival Fertilizer

• Weight: 15 lb

Best for: Potassium-Forward Fall Formula.

Why it ranks #3: The 10-0-20 formula and stated fall use support winter preparation, but its listed grass suitability does not specifically name St. Augustine.

Jonathan Green’s 10-0-20 formula puts potassium at the forefront of its winter-preparation profile, alongside a stated goal of strong root growth. The granular fall fertilizer is aimed at lawns recovering from summer stress and storing nutrients for colder months, with spring turf health as the intended payoff.

The 10-0-20 formula is identified as a balanced nutrient blend, and the listing connects fall use with nutrient storage and winter survival. Those claims make it relevant to buyers looking for one seasonal product to address summer recovery and preparation for colder weather. Its granular form supports spreader-style application, although the supplied details do not give a spreader setting or coverage area. The product is presented for thick, green turf and stronger roots rather than weed control.

Skip it if you need a stated square-foot coverage before buying; Natural Alternative 20004 lists coverage of 6,000 square feet.

Consider it if you want a granular, potassium-forward fall fertilizer for root support and winter preparation. Its listing does not state a coverage area or application rate, so those details may matter when planning a spreader application.

Listed on Amazon as: Jonathan Green & Sons Inc 12400 10-0-20 Winter Survival Fall Fertilizer, 1 (Single Pack)

#4 · Controlled-Release Nitrogen

4. Green Thumb Winterizer

• Weight: 12.6 lb
• Form: Powder

Best for: Extended-Feed Winterizer Pick.

Why it ranks #4: Its 32-0-10 formula has 50% controlled-release nitrogen and 2% iron, feeds up to 16 weeks, and covers 5,000 square feet.

Up to 16 weeks of continuous feeding distinguishes Green Thumb GT58105 from a single-application fertilizer without a stated feeding duration. Its 32-0-10 formula also includes 2% iron, combining winter stress support and root-system goals with a specific deep-greening ingredient for lawns ahead of colder weather.

Green Thumb says the fertilizer helps lawns survive winter stress and encourages a stronger, deeper root system, making it a fall-oriented choice for buyers prioritizing root support. The 50% controlled-release nitrogen is listed alongside feeding for up to 16 weeks, which gives the application a longer stated feeding window. Coverage is up to 5,000 square feet, a useful planning figure for matching the bag to a lawn. The listed 2% iron supports the product’s deep-greening claim.

Skip it if you want an explicitly stated St. Augustine fit; Espoma Turf-Tone lists St. Augustine among its suitable grasses.

This fits lawn owners who want a defined coverage area and an extended feeding window in a fall winterizer. If matching fertilizer to a particular grass is essential, the supplied listing does not name compatible species.

Listed on Amazon as: Green Thumb GT58105 Winterizer Lawn Fertilizer, 32-0-10 Formula, 5,000-Sq. Ft. Coverage – Quantity 1

#5

5. GRO-Fine Winterizer

• Weight: 13 lb
• Form: Granules

Best for: High-Nitrogen Root Support.

Why it ranks #5: The phosphorus-free 30-0-10 granular formula covers 5,000 square feet and is presented for fall root support, but lacks an explicit St. Augustine use claim.

The 30-0-10 formula and 5,000-square-foot coverage give Knox Fertilizer GRO-Fine a clearly defined role as a high-nitrogen fall winterizer. Its listing connects the granular fertilizer with root development, winter-stress resilience, and early spring green-up, while noting that the formula is phosphorus-free.

GRO-Fine is supplied as granules in a 13-pound bag, with directions to spread it evenly over 5,000 square feet. That stated area helps buyers plan coverage, while the 30-0-10 formula is described as supporting strong root development and a thicker lawn after winter stress. The product also targets early spring green-up. Its phosphorus-free formula may suit buyers seeking that specific nutrient profile, though the supplied facts do not name particular grass species.

Skip it if you want a fertilizer that explicitly names St. Augustine; Espoma Turf-Tone lists that grass among its intended uses.

This suits buyers prioritizing a stated coverage area, high-nitrogen formula, and root support for fall preparation. The product information does not name grass species, so use its label guidance when deciding whether it fits your turf.

Listed on Amazon as: GRO-Fine 13 Lb. 5000 Sq. Ft. 30-0-10 Winterizer Fall Fertilizer – 1 Each

#6

6. Natural Alternative Winter Lawn Fertilizer

• Form: Granules

Best for: Late-Fall Root Feeding.

Why it ranks #6: Its 20-0-4 formula is phosphorus-free and covers 6,000 square feet; the listed late-October to mid-November timing is specific but not regional.

A late October to mid-November application window gives Natural Alternative Winter Lawn Fertilizer a specific seasonal niche. Its 20-0-4 formula is enriched with Protilizer seed and plant activator, and the listing says it feeds roots through winter while covering 6,000 square feet.

This granular fertilizer’s stated coverage of 6,000 square feet provides a useful planning figure for larger lawns. The listing connects its carbohydrates with winter energy reserves and spring activation, while also describing root feeding through harsh winter months. Its phosphorus-free formula is presented as supporting clean rivers, lakes, bays, and wetlands. The specified late-fall window helps buyers time the application, but the supplied facts do not identify particular grass types or give a spreader setting.

Skip it if you need fertilizer compatibility explicitly stated for St. Augustine; Espoma Turf-Tone lists that grass among its suitable uses.

Consider this for a late-fall root-feeding application when its October-to-November timing and 6,000-square-foot coverage suit your lawn. The supplied listing does not name grass types, so account for that when selecting it for St. Augustine.

Listed on Amazon as: Natural Alternative Winter Lawn Fertilizer 20-0-4 Enriched with Protilizer Seed & Plant Activator Application 5 (20004)

#7

7. JRK Winterizer Lawn Fertilizer

• Weight: 50 lb
• Form: Granules

Best for: October Potash Application.

Why it ranks #7: The 20-0-12 formula emphasizes potash and the 18-pound bag covers 5,000 square feet, but its October timing may not suit every location.

An October application and extra potash define JRK SEED Winterizer’s seasonal use: the listing says potassium helps grass emerge healthy when snow melts. The 20-0-12 formula and stated 5,000-square-foot coverage for the 18-pound bag give buyers a timing cue and a practical lawn-area reference.

JRK recommends applying this granular winterizer in October, framing it as a fall step for winter preparation. Its 20-0-12 formula includes extra potash, which the listing associates with healthy growth after snow melts. The 18-pound bag is stated to cover 5,000 square feet, helping with application planning. Together, the timing, nutrient ratio, and coverage make the product straightforward to assess for a fall routine, though the supplied information does not identify specific grass types.

Skip it if you need an explicit St. Augustine compatibility statement; Espoma Turf-Tone names St. Augustine among its suitable grasses.

JRK Winterizer fits lawn owners seeking a defined October application and a stated coverage area for a granular fall product. Check grass-type suitability separately, since the supplied product details do not identify specific species.

Listed on Amazon as: JRK Winterizer Lawn Fertilizer (18 lbs)

#8

8. Espoma Organic All-Purpose Winterizer

• Weight: 30 lb
• Form: B00Y66LJ1I

Best for: All-Grass Winterizer Listing.

Why it ranks #8: The title identifies it as an organic winterizer for all grasses with 5,000-square-foot coverage, but supplied details omit its formula and application directions.

The product title identifies this Espoma fertilizer as an organic winterizer for all grasses and gives a 5,000-square-foot coverage figure. That broad grass description makes it relevant to buyers looking for a winterizer for St. Augustine, although the supplied details provide little additional information about its formula or application.

The available listing names an all-grass use and states coverage of 5,000 square feet, giving shoppers two basic selection points: broad turf applicability and lawn-area planning. Espoma identifies the item as organic and as a winterizer, but the supplied facts do not specify an N-P-K ratio, ingredient list, application timing, or application method. That limited detail means buyers should rely on the product label for operational guidance rather than assume a particular spreader setting or seasonal schedule.

Skip it if you need a stated nutrient ratio and fall application guidance; Espoma Turf-Tone lists an 8-0-5 formula and fall use.

This may suit buyers seeking an all-grass Espoma winterizer with a stated 5,000-square-foot coverage figure. Its listing is sparse on formula and application instructions, so it is a limited choice if those specifics guide your lawn-care plan.

Listed on Amazon as: Espoma Organic All-Purpose Winterizer for All Grasses 5000 sq ft

#9

9. Scotts WinterGuard Fall Weed & Feed

• Weight: 36 lb
• Form: Granule

Best for: Fall Weed-and-Feed Treatment.

Why it ranks #9: It combines fall fertilizer with control of over 50 listed weeds, but requires a wet lawn and actively growing weeds at 60°F to 90°F.

Control of more than 50 listed lawn weeds is the defining feature of Scotts WinterGuard Fall Weed & Feed5, which combines weed treatment with fall feeding. It is aimed at lawns where weeds are actively growing, while its fertilizer component supports recovery and stronger roots ahead of winter.

This product combines weed control and fertilizer, potentially consolidating two fall lawn-care tasks into one application. Scotts lists weeds including clover, dandelion, and plantain, and specifies application to a wet lawn while weeds are actively growing and temperatures remain consistently between 60°F and 90°F. The feeding component is described as helping grass recover from summer damage and build roots for harsh winter conditions. Those timing requirements make it a more condition-specific choice than a general fall fertilizer.

Skip it if you want a simple fertilizer application without weed-control timing conditions; JRK SEED Winterizer lists October application for winter preparation.

Choose this when fall weeds and feeding are both on the lawn-care list and the stated application conditions can be met. It is less suitable for a routine feed when weeds are not actively growing.

Listed on Amazon as: Scotts Turf Builder WinterGuard Fall Weed & Feed5, 33.84 lbs.

#10

10. GS Plant Foods Fall Resilience Kit

• Form: Liquid

Best for: Multi-Product Fall Resilience Kit.

Why it ranks #10: The three-gallon liquid kit includes a fertilizer, humic acid soil conditioner, and sea mineral supplement, but gives no formula, coverage, or St. Augustine claim.

Three liquid components—organic winterizer fertilizer, humic acid soil conditioner, and sea mineral supplement—make this GS Plant Foods kit a combined fall-care approach. It is presented as helping grass build roots and store nutrients for spring green-up, with the separate products addressing multiple parts of seasonal preparation.

The kit contains three one-gallon products, offering a multi-part approach rather than a single fertilizer alone. GS Plant Foods identifies the components as an organic winterizer, a humic acid soil conditioner, and a sea mineral supplement, so buyers can consider fertilizer and soil-conditioning roles together. The description focuses on deep roots, nutrient storage, and spring green-up as temperatures fall. The listed liquid form distinguishes its application format, but the supplied information does not provide rates or specific spreading equipment.

Skip it if you need a known square-foot coverage and straightforward rate; Natural Alternative 20004 states coverage of 6,000 square feet.

This kit suits buyers interested in a liquid, multi-component fall routine spanning fertilizer, soil conditioning, and mineral supplementation. Application planning may require additional label information because the supplied details do not state rates or coverage.

Listed on Amazon as: GS Plant Foods Ultimate Fall Lawn Resilience Kit – Organic Winterizer Fertilizer, Humic Acid Soil Conditioner, & Sea Mineral Supplement (3 x 1 Gallon)