Garden Last updated · owner ratings verified July 2026
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Side by side
| Our pick Scotts Scotts Turf Builder Bonus S Southern Weed & Feed2 Better overall $35–50 Check price | Scotts Scotts Turf Builder Weed and Feed 3 DO NOT use on St. Augustine $25–35 Check price | Spectracide Spectracide Weed Stop for St. Augustine & Centipede Concentrate Better value $12–18 Check price | Spectracide Spectracide Weed Stop for Lawns Plus Crabgrass Killer DO NOT use on St. Augustine $15–22 Check price | |
|---|---|---|---|---|
| What owners rate it | ||||
| Owner rating | 4.5 / 5 (6,513) | 4.4 / 5 (36,508) | 4.3 / 5 (156) | 4 / 5 (5,343) |
| Specifications | ||||
| Active ingredient | Atrazine | Broadleaf herbicide blend, not atrazine | Atrazine | Broadleaf and crabgrass herbicide blend |
| Labeled for St. Augustine | Yes — St. Augustine and centipede on label | No — label prohibits St. Augustine | Yes — St. Augustine and centipede on label | No — label prohibits St. Augustine |
| Form | Granular | Granular | Liquid concentrate for a pump sprayer | Ready to use, 1 gallon |
| Fertilizer included | Yes — Turf Builder feed included | Yes — Turf Builder feed included | No | No |
| Weeds controlled | Broadleaf plus several annual grassy weeds | Broadleaf weeds in cool-season lawns | Broadleaf plus several annual grassy weeds | Broadleaf plus crabgrass |
| Temperature limits | Do not apply in high summer heat — check label ceiling | Cool-season application windows | Do not apply in high summer heat — check label ceiling | Standard growing-season application |
| Coverage | Up to 10,000 sq. ft. | Up to 5,000 sq. ft. | Depends on dilution and spot treatment | Small areas per container |
| How it is applied | Broadcast spreader, on damp grass | Broadcast spreader, on damp grass | Mix and spray, spot or broadcast | Spray direct from the container |
| Who it suits | ||||
| Best for | A whole St. Augustine lawn with weeds throughout that also needs feeding | Northern lawns — bluegrass, fescue, ryegrass | Spot spraying patches instead of dosing the whole yard | Cool-season and bermuda lawns with crabgrass |
Ratings are aggregated Amazon owner ratings, not our own testing. Figures verified July 2026.
Pros and cons
Scotts Turf Builder Bonus S Southern Weed & Feed2
- Labeled specifically for southern grasses including St. Augustine and centipede — this is the correct Scotts bag
- Atrazine controls both broadleaf weeds and several annual grassy weeds, which most selective herbicides do not
- Feeds the lawn at the same time, and a thick lawn is the most effective long-term weed control there is
- Covers a large area per bag and applies with any broadcast spreader
- Blanket-treats the entire lawn whether or not the whole lawn has weeds
- Fertilizer timing and herbicide timing do not always want to be the same week
- Atrazine has a temperature ceiling — applying in high summer heat risks damaging the turf you are trying to protect
- Most expensive product here per application
Scotts Turf Builder Weed and Feed 3
- One of the largest owner-rating pools of any lawn product sold, and deservedly so on the right grass
- Genuinely effective on dandelion, clover and chickweed in cool-season turf
- Feeds and treats in one pass with a standard broadcast spreader
- Cheaper per bag than the Bonus S
- The label prohibits use on St. Augustine, and it will damage or kill it — this is the bag people buy by mistake
- Also excluded on centipede, carpetgrass, dichondra and bentgrass
- Bought on brand familiarity rather than label, which is exactly how southern lawns get ruined
- Included in this comparison as a warning, not as a candidate
Spectracide Weed Stop for St. Augustine & Centipede Concentrate
- The correct Spectracide product for these grasses, with atrazine as the active ingredient
- Concentrate mixes into a pump sprayer, so you treat only the areas that actually have weeds
- Dramatically cheaper per thousand square feet than any granular weed and feed
- Lets you separate weed control from fertilizing, which is agronomically the better practice
- Small rating pool compared with the mainstream products here, which reflects how few people buy the correct bottle
- You have to measure, mix and clean a sprayer, and mixing errors are on you
- No fertilizer, so a thin lawn stays thin and refills with weeds
- Same atrazine heat restriction as the Scotts Bonus S
Spectracide Weed Stop for Lawns Plus Crabgrass Killer
- Ready to use with a hose-end or wand — no mixing at all
- Very broad weed spectrum including crabgrass, which atrazine handles less completely
- Large owner-rating pool and a familiar bottle on every shelf
- Fast visible results on the grasses it is meant for
- The label excludes St. Augustine, centipede, dichondra, carpetgrass and bahia — it will injure them
- Sits on the same shelf as the correct Spectracide bottle in near-identical packaging
- Ready-to-use dilution costs far more per treated area than a concentrate
- Included here as the warning half of the Spectracide line-up
Decision factors
What you actually pay
Price per bottle hides the number that matters, which is cost per thousand square feet treated. The Spectracide concentrate is $12–18 and, diluted into a pump sprayer, treats a large area for that money. The ready-to-use gallon is $15–22 and covers a fraction as much ground because you are paying to ship water. Scotts Bonus S is $35–50 but covers up to 10,000 square feet and includes a full fertilizer application.
Where the Scotts money goes. Into the feed. Bonus S is a fertilizer with atrazine in it, and the fertilizer half is doing real work — a dense, well-fed St. Augustine lawn crowds out weeds far more effectively than any herbicide does. Judged as weed control alone it is expensive; judged as a spring feed that also handles weeds, it is reasonable.
Where the Spectracide money goes. Almost nowhere, which is the point of a concentrate. You are buying atrazine and mixing it yourself, and the saving over any ready-to-use product is large.
The costs people forget. A decent pump sprayer is $25–40 and lasts years; buying ready-to-use bottles instead costs more than that within two seasons. Atrazine is a restricted product in some places — it is not sold in New York and is limited in parts of Wisconsin — so check availability before planning around it. And factor in the cost of getting it wrong: replacing a damaged section of St. Augustine means sod, and sod runs several hundred dollars for even a modest patch, which is more than a decade of correctly chosen herbicide.
Which one fits you
- Weeds through the whole lawn, and it needs feeding Scotts Turf Builder Bonus S Treats and fertilizes in one spreader pass with an active ingredient that is on label for St. Augustine.
- A few patches of weeds in an otherwise good lawn Spectracide Weed Stop for St. Augustine & Centipede Spot spraying costs a fraction as much and keeps herbicide off the 90 percent of the lawn that does not need it.
- You garden in New York or a restricted county Neither — check local availability first Atrazine is not sold in some states and is limited in others, so the correct product for St. Augustine may not be legally available to you.
- It is already high summer Wait, then Scotts Bonus S Atrazine has a temperature ceiling on the label, and applying in serious heat risks damaging the turf rather than the weeds.
If neither is right
- Southern Ag Atrazine St. Augustine Weed Killer, 32 oz The same active ingredient sold plainly as what it is, usually at the lowest cost per treated area of anything in this category. No fertilizer and no branding, which suits anyone comfortable mixing their own.
- Plus Turf Nutsedge Killer with Pre-Mixed Surfactant Nutsedge is the weed atrazine handles least convincingly, and it is the most common complaint from southern lawn owners who did everything else right. Confirm St. Augustine tolerance on the label before applying.
- Espoma Organic Weed Preventer Plus Lawn Food (corn gluten) The non-herbicide route. Corn gluten meal suppresses germinating weed seeds and feeds the lawn, and it does nothing at all to weeds that are already growing. Slow, partial, and the only option if you will not use a synthetic herbicide.
Which should you buy?
Check the label before you check the brand. Both Spectracide and Scotts sell a product that is safe on St. Augustine and a far more popular product that will damage it, and the packaging looks broadly the same. For a whole lawn that needs feeding as well as weeding, buy Scotts Turf Builder Bonus S — it is atrazine-based, it is on label for southern grasses, and the fertilizer half does genuine long-term work. For patches of weeds in an otherwise decent lawn, buy the Spectracide St. Augustine and Centipede concentrate and spot spray, which costs a fraction as much and puts far less chemical on your yard.
Why is St. Augustine so easy to kill with the wrong product?
Because most lawn herbicides in the United States are formulated for cool-season grasses, and the chemistry that leaves bluegrass and fescue unharmed does not leave St. Augustine unharmed. Several common broadleaf actives injure it outright, and the Floratam variety in particular is sensitive to products that other St. Augustine strains tolerate.
That is why atrazine holds the position it does in southern lawn care: it is one of the few widely available selective herbicides that St. Augustine and centipede tolerate at label rates, and it happens to control both broadleaf weeds and several annual grassy weeds at the same time. When a southern lawn product does not name St. Augustine on the label, assume the omission is deliberate.
How do you tell the right bottle from the wrong one?
Read the front panel for your grass name, then read the back for the exclusions. Every product in this comparison lists which grasses it may be used on and which it may not, and those lists are legally binding rather than advisory. Scotts Bonus S names southern grasses; Scotts Turf Builder Weed and Feed excludes St. Augustine. Spectracide's St. Augustine and Centipede bottle names them in the product title; Spectracide's much better-selling Weed Stop Plus Crabgrass Killer excludes them.
The tell is usually the word southern, or the presence of atrazine in the active ingredient panel. If you are standing in the aisle unsure, photograph the active ingredient panel and check it before you leave. Getting this wrong does not produce a slightly disappointing result — it produces dead patches that need re-sodding.
When should you apply either of these?
Spring and fall, and not in the heat of summer. Atrazine carries a temperature restriction on its label because applying it to St. Augustine in high heat can injure the turf, and the same warm weather that stresses your grass also makes any herbicide harsher. Aim for the period when weeds are actively growing but daytime temperatures are moderate.
Two other timing rules matter as much. Do not apply before heavy rain, because a granular product washes off and a liquid needs several hours on the leaf to work — does weed killer work in the rain covers the windows. And do not mow for a few days either side, since you want leaf surface for the herbicide to land on and you do not want to cut off the treated tissue. Our guide to the best temperature to spray weed killer sets out the ranges.
Is a weed and feed better than spraying?
It is more convenient and it is less precise, which is the whole trade. A granular weed and feed treats every square foot equally, including the 90 percent of a decent lawn that has no weeds at all, and it locks your herbicide timing to your fertilizer timing even when those two jobs want different weeks. It also relies on granules sticking to damp weed leaves, which is why the label tells you to apply to a wet lawn.
Spot spraying with a concentrate uses a fraction of the chemical, costs far less, and can be repeated on the patches that survive. The catch is that it does nothing for the underlying problem. Weeds colonize thin turf, so a lawn that keeps producing weeds needs feeding, correct mowing height and proper watering more than it needs another herbicide pass — see our spring weed and feed guide for how to sequence the two.
What about pets, children and runoff?
Keep everyone off a treated lawn until a granular product has been watered in and the lawn has dried, or until a liquid application has dried completely, and follow the specific re-entry interval printed on your label rather than a general rule. Atrazine is water-soluble and moves readily, which is precisely why it is restricted in some jurisdictions — do not apply it before heavy rain, near a storm drain, or on a slope running to a waterway.
If a household member cannot be kept off the grass, corn gluten products and cultural control are the honest alternatives, and both are slower and less complete. Our page on weed killer and pet safety goes through what the labels actually require rather than what people assume.
The bottom line
This comparison is decided by the label, not the brand. Scotts Turf Builder Bonus S is the better whole-lawn product for St. Augustine, combining atrazine with a real feed and covering a large area per bag. Spectracide's St. Augustine and Centipede concentrate is the better tool for targeted work and is dramatically cheaper per treated square foot. Both brands also sell hugely popular products that will damage St. Augustine, and buying one of those by mistake costs more than every correct product on this page put together.
For the full field, see our St. Augustine weed killer roundup, and the deeper looks at Scotts Bonus S and Spectracide Weed Stop. Our Ortho vs Spectracide comparison covers the other brand on the same shelf. We rank from aggregated owner ratings and expert consensus rather than first-hand testing — see how we rank.