What Is Prodiamine?
If you’ve spent any time researching lawn care in South Florida, you’ve probably come across the word prodiamine. It’s the active ingredient in some of the most widely used pre-emergent herbicides on the market, including the professional-grade product Barricade. For homeowners across Palm Beach County—whether you’re managing a backyard St. Augustine lawn or overseeing turf for an HOA—prodiamine is one of the most effective tools available for keeping weeds out of your grass before they ever appear.
Prodiamine belongs to the dinitroaniline family of herbicides. It is strictly a pre-emergent, meaning it prevents weeds from growing in the first place. It will not kill weeds that are already established in your lawn. Think of it less like a weed killer and more like a protective barrier laid across the top layer of your soil.
How Prodiamine Works
Prodiamine’s mode of action is classified as Group 3 — microtubule assembly inhibition. That sounds complex, but the concept is relatively straightforward.
When a weed seed germinates in soil that has been treated with prodiamine, the young seedling absorbs the herbicide through its developing roots and shoots. Prodiamine blocks the plant’s ability to produce tubulin, a protein essential for building microtubules. Microtubules are the tiny scaffolding structures inside cells that enable cell division (mitosis). Without them, the seedling’s cells cannot divide, and the plant dies before it ever breaks the soil surface.
This is why timing matters so much: prodiamine must be in the soil before weed seeds germinate. Once a weed has emerged and developed beyond the seedling stage, prodiamine will have no effect on it.
Key Characteristics
Low water solubility: Prodiamine binds tightly to soil particles rather than dissolving in water. This means it stays in the top layer of soil where weed seeds germinate and is far less likely to leach deeper into the ground with heavy rainfall—a huge advantage during South Florida’s rainy season.
Long half-life: Prodiamine has a soil half-life of approximately 120 days. It degrades primarily through microbial activity, not volatilization or sun exposure (once watered in). This gives it one of the longest residuals of any commonly used pre-emergent.
No post-emergent activity: Prodiamine will not control weeds that have already sprouted. If you see visible weeds in your lawn, you’ll need a separate post-emergent herbicide to deal with them.
Which Weeds Does Prodiamine Control?
Prodiamine is broad-spectrum when it comes to annual grassy and broadleaf weeds. In South Florida lawns, it is particularly effective against:
| Grassy Weeds | Broadleaf Weeds | Others |
|---|---|---|
| Crabgrass (smooth & large) | Spurge | Poa annua (annual bluegrass) |
| Goosegrass | Chickweed | Bittercress |
| Signalgrass | Henbit | Foxtail |
| Witchgrass | Oxalis (some species) | Carpetweed |
What Prodiamine Will NOT Control
No pre-emergent does everything, and prodiamine has some notable gaps. Understanding these limitations helps you plan a complete weed management strategy:
Nutsedge (yellow and purple): Sedges are not true grasses, and they reproduce from underground tubers and rhizomes—not seeds. Since prodiamine only targets germinating seeds, it has zero effect on nutsedge. You’ll need a dedicated sedge herbicide like sulfentrazone (Dismiss) or halosulfuron (SedgeHammer) to control these.
Established perennial weeds: Dandelions, dollarweed, clover, and other perennial weeds that are already growing won’t be affected. These require post-emergent treatment.
Large-seeded broadleaf weeds: Some larger broadleaf species are less consistently controlled. Prodiamine is known to be weak on American burnweed, common groundsel, morningglory, ragweed, and dogfennel.
Kyllinga: Like nutsedge, kyllinga spreads via rhizomes and is not effectively suppressed by prodiamine alone.
When to Apply Prodiamine in South Florida
Timing is one of the most important factors in getting good results from prodiamine. In South Florida, our climate is subtropical—soil temperatures rarely drop below 55°F, and weeds can germinate almost year-round. That makes our application schedule different from what you’d follow in the rest of the country.
The South Florida Calendar
| Round | Timing | Purpose | Target Weeds |
|---|---|---|---|
| Spring – Round 1 | Early February | Primary barrier against summer annuals | Crabgrass, goosegrass, spurge |
| Spring – Round 2 | Late March / Early April | Extend protection into early summer | Late-germinating grassy weeds |
| Fall – Round 1 | Mid to Late October | Prevent winter annual weeds | Poa annua, chickweed, henbit |
| Fall – Round 2 (optional) | December / January | Extend fall barrier into spring | Late winter broadleaf weeds |
The general principle: apply prodiamine before soil temperatures reach the germination window for your target weeds. For summer weeds like crabgrass, the threshold is around 55–65°F. For winter annuals like poa annua, the window opens as soils cool below 70°F in fall. In Palm Beach County, soil temperatures often stay warm enough year-round that split applications (two lighter applications instead of one heavy dose) are the most reliable approach.
It’s safe to apply prodiamine up to three times per growing season, as long as you don’t exceed the annual maximum rate listed on the product label for your turf type.
How Long Does Prodiamine Last?
One of prodiamine’s biggest selling points is its longevity. At standard application rates, each application typically provides about three months of pre-emergence protection. At higher rates (within label limits), some users report four to five months of control on warm-season turf.
However, South Florida’s heat and microbial activity break down herbicides faster than in cooler regions. That’s why split applications every 8–12 weeks tend to outperform a single heavy application here. The combination of high soil temperatures, frequent irrigation, and biological activity in our sandy soils means the barrier degrades more quickly than it might in, say, the Carolinas or Midwest.
Prodiamine’s half-life of roughly 120 days is significantly longer than dithiopyr (around 40 days), which is one reason professionals in southern states tend to favor it as a first-choice pre-emergent.
How to Apply: Liquid vs. Granular
Prodiamine is available in two primary forms, and both are effective when applied correctly. Here’s how they compare:
Granular Prodiamine
Granular products (like the popular 0-0-7 formulations) consist of small fertilizer prills coated with prodiamine. You apply them with a standard broadcast or rotary spreader—the same equipment you’d use for fertilizer. When you water the lawn afterward, the prodiamine washes off the granules and into the top layer of soil, forming the weed barrier.
Best for: Homeowners who are comfortable with a spreader and want the easiest possible application. No mixing or calibration is required beyond setting your spreader to the correct setting.
Tip: Overlap your spreader passes so that each row throws product back to the wheel tracks of the previous pass. This ensures even coverage and avoids streaks of unprotected turf.
Liquid Prodiamine (WDG)
Prodiamine 65 WDG (water-dispersible granule) is a concentrated powder that you dissolve in water and apply with a pump sprayer or backpack sprayer. It’s the same active ingredient—just delivered as a liquid spray instead of dry granules.
Best for: Experienced DIYers or professionals who are comfortable calibrating a sprayer. Liquid offers more precise coverage, can be targeted to specific zones, and is significantly cheaper per application over time.
Key consideration: Prodiamine WDG has a yellow color and can stain concrete, pavers, and clothing. Be careful around driveways and sidewalks. The staining is less severe than older products like pendimethalin, but it’s still worth noting.
Which Should You Choose?
Both work equally well when applied correctly and watered in. If you’re new to lawn care or prefer simplicity, go granular. If you want to save money and have spray equipment, liquid WDG is the way to go. Either way, watering in within 48 hours is critical—without it, the product sits on the surface and won’t form the soil barrier.
Safety Information
Prodiamine is considered a low-toxicity herbicide when used according to label directions. That said, every herbicide deserves respect and proper handling.
Personal protective equipment (PPE): At minimum, wear gloves, protective eyewear, and long-sleeved clothing during mixing and application. Prodiamine can be irritating if it contacts skin or eyes.
Pets and children: Once the product has been watered in and the lawn surface has dried, the risk to pets and children is minimal. Still, it’s good practice to keep them off the treated area until after you’ve irrigated and the lawn is dry.
Environmental considerations: Prodiamine is toxic to fish and aquatic organisms. Avoid application near ponds, canals, lakes, or storm drains. In Palm Beach County, this is especially important given our proximity to the Everglades and coastal waterways. Always observe buffer zones listed on the label and never apply before a heavy rain event.
Turf safety: Prodiamine is safe for established St. Augustine, Bermuda, and Zoysia grass when applied at label rates. However, do not apply it to newly seeded or newly sodded lawns—it will prevent new grass from rooting properly. Wait until turf is fully established (typically after at least two mowings for sod) before applying.
Overseeding: Because prodiamine stops all seed germination, you cannot overseed for at least 6–8 weeks after an application. If you plan to overseed, factor this into your application schedule.
Prodiamine vs. the Alternatives
Prodiamine is the dominant pre-emergent in the lawn care industry, but it’s not the only option. Here’s how it stacks up against the most common alternatives used in South Florida:
Prodiamine vs. Dithiopyr (Dimension)
This is the comparison most homeowners and lawn pros encounter. Both are excellent pre-emergents, but they have distinct strengths.
| Factor | Prodiamine (Barricade) | Dithiopyr (Dimension) |
|---|---|---|
| Mode of Action | Pre-emergent only | Pre-emergent + early post-emergent on young crabgrass |
| Half-Life | ~120 days | ~40 days (decreases in heat) |
| Leaching Risk | Low — binds tightly to soil | Higher — more water-soluble, can volatilize |
| Cost | Less expensive | More expensive |
| Staining | Yellow staining possible on hard surfaces | Clear, no staining |
| Best Use in S. Florida | First application of the season (early Feb) | Second application or if you’re running late |
The bottom line: Prodiamine is the better first-round pre-emergent for South Florida because it resists leaching in our heavy rains, lasts longer in the soil, and costs less. Dithiopyr is an excellent complement for a second application, particularly because it can catch young crabgrass seedlings that may have slipped through. Many professionals use both in a split-application approach—prodiamine first, dithiopyr second.
Prodiamine vs. Atrazine
Atrazine is extremely common in South Florida—you’ll find it in most store-bought “weed and feed” products marketed for St. Augustine grass. But it serves a fundamentally different purpose than prodiamine.
Atrazine is primarily a post-emergent herbicide. It kills actively growing broadleaf weeds by inhibiting photosynthesis. While it does have some pre-emergent properties, its residual control is short—typically about 60 days—and it is weak against grassy weeds like crabgrass and goosegrass.
Prodiamine, on the other hand, is far superior for grassy weed prevention. It has no post-emergent activity at all. The two products are complementary, not interchangeable. A strong South Florida lawn care program might use prodiamine for prevention and atrazine for cleanup of broadleaf weeds that break through.
Important note: Atrazine should only be used on St. Augustine and centipede grass. It can severely damage or kill Bermuda, Zoysia, and Bahia if applied incorrectly or in warm weather. Prodiamine is safe across all of these turf types.
Prodiamine vs. Pendimethalin (Pendulum)
Pendimethalin was one of the original dinitroaniline pre-emergents and is still available in granular “weed and feed” combos. It works similarly to prodiamine but has a shorter residual and is notorious for staining everything yellow—driveways, shoes, equipment, and even skin. Prodiamine offers a longer-lasting barrier with significantly less staining potential. For most South Florida homeowners, prodiamine is the clear upgrade.
Prodiamine vs. Indaziflam (Specticle)
Indaziflam is the most powerful and longest-lasting pre-emergent available, with residual control that can stretch up to nine months. It controls both grassy and broadleaf weeds with exceptional consistency. The catch? It’s extremely expensive (around $1,700 per gallon) and primarily used by professional lawn care companies. It also requires very precise application—overuse can damage desirable turf and should not be used more than two consecutive years without rotation. For homeowners, prodiamine offers the best balance of effectiveness, longevity, and affordability.
South Florida–Specific Tips
Managing a lawn in Palm Beach County isn’t quite like managing one anywhere else. Here are some prodiamine tips tailored to our local conditions:
Sandy soils break down herbicides faster. South Florida’s sandy, well-draining soils support more microbial activity and drain water quickly. This can shorten prodiamine’s effective window. Splitting your annual rate across two or three applications gives more consistent coverage than one heavy dose.
Respect fertilizer blackout periods. While most pre-emergent herbicides are not subject to local fertilizer blackout ordinances, the same environmental principles apply. Never apply any lawn product before a heavy rain event or near storm drains that feed into local canals and waterways.
Pair prodiamine with a post-emergent plan. Even with perfect pre-emergent timing, some weeds will break through—especially nutsedge and perennial broadleaves. Have a post-emergent product like Celsius (for broadleaves on St. Augustine) or Certainty/Dismiss (for sedges) ready for spot treatments throughout the season.
Don’t apply to new sod. If you’ve recently had sod installed, wait until it’s fully rooted and you’ve mowed at least twice before applying prodiamine. Applying too early can inhibit root establishment.
Monitor soil temperatures, not calendar dates. South Florida’s weather doesn’t always follow the calendar. The UF/IFAS Florida Automated Weather Network and several lawn care apps can give you real-time soil temperature data for your area.
Quick-Reference Application Checklist
- Measure your lawn — Know your square footage so you can calculate the right amount of product.
- Choose your form — Granular for simplicity, liquid WDG for precision and cost savings.
- Apply at the right time — Early February for spring (Round 1), late March for spring (Round 2), mid-October for fall.
- Follow label rates — More is not better. Exceeding the rate can damage your turf’s root system.
- Water it in — Apply at least ½ inch of irrigation within 48 hours of application. This is the most critical step.
- Don’t disturb the soil — Avoid aerating, dethatching, or heavy raking for several weeks after application.
- Plan your second round — Mark your calendar for a follow-up application 8–12 weeks later.
Let Floridist Handle Your Weed Prevention
If all of this sounds like more than you want to manage on your own, we get it. Timing applications, choosing the right products, adjusting for weather—it adds up. That’s exactly what Floridist’s treatment programs are built for.
We serve homeowners and HOAs throughout Palm Beach County—from Jupiter and Palm Beach Gardens to West Palm Beach, Wellington, Boynton Beach, Delray Beach, and Boca Raton. Our weed control programs are designed around South Florida’s exact climate, soil conditions, and turf types. We handle the product selection, timing, and application so you don’t have to.
Whether you need a standalone pre-emergent application or a full-season fertilization and weed control plan, we’re here to help.
Call or text: 561-941-GROW
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