Pest Control
Andersons Barricade Pre-Emergent: Spring Fertilizer & Soil Guide
Applying a pre-emergent herbicide is only half the battle in spring turf management. While an Anderson Barricade pre emergent application effectively halts crabgrass, goosegrass, and Poa annua by inhibiting root cell division in germinating seeds, it provides zero nutritional value to your existing turf. To achieve a dense, weed-free lawn, turf managers must integrate prodiamine (the active ingredient in Barricade) with a strategic spring fertilizer program that accounts for soil chemistry, organic matter levels, and precise nutrient timing.
This guide details the agronomic intersection of pre-emergent weed control and soil nutrition, providing exact application rates, formulation comparisons, and soil-specific adjustments for the 2026 growing season.
The Science of Prodiamine and Soil Organic Matter
Prodiamine is a dinitroaniline herbicide with a high Koc (organic carbon partition coefficient). In practical terms, this means the chemical binds tightly to soil organic matter (OM) and clay particles. It does not move easily through the soil profile, which is why it creates an effective barrier at the surface where weed seeds germinate. However, this binding characteristic dictates your application rate based on your soil test results.
Soil Organic Matter (OM) Rule of Thumb:
• High OM (>5%) or Heavy Clay: The soil will 'tie up' more of the active ingredient. You must apply the maximum label rate to ensure enough free prodiamine remains in the soil water to kill germinating seeds.
• Low OM (<2%) or Sandy Soils: The chemical binds less readily. Applying the maximum rate risks leaching the herbicide past the germination zone, wasting product, and potentially causing root pruning (phytotoxicity) to your turf. Always use the minimum label rate on sandy soils.
• High OM (>5%) or Heavy Clay: The soil will 'tie up' more of the active ingredient. You must apply the maximum label rate to ensure enough free prodiamine remains in the soil water to kill germinating seeds.
• Low OM (<2%) or Sandy Soils: The chemical binds less readily. Applying the maximum rate risks leaching the herbicide past the germination zone, wasting product, and potentially causing root pruning (phytotoxicity) to your turf. Always use the minimum label rate on sandy soils.
Before broadcasting any Andersons Barricade product, review your most recent soil test. If your Cation Exchange Capacity (CEC) is low (below 10 meq/100g), your soil lacks the binding sites to hold both nutrients and herbicides effectively, requiring split applications of both fertilizer and pre-emergent.
Formulation Showdown: Granular vs. WDG
The Andersons brand offers prodiamine in multiple formulations. Choosing the right one depends on your equipment, budget, and whether you want a standalone pre-emergent or a combination fertilizer-weed-and-feed product.
| Feature | Andersons 0.48% Granular | Barricade 65 WDG (Water Dispersible) |
|---|---|---|
| Active Ingredient | 0.48% Prodiamine | 65% Prodiamine |
| Application Rate (per 1k sq ft) | 1.8 to 3.6 lbs | 0.185 to 0.46 oz |
| Equipment Needed | Rotary or Drop Spreader | Backpack or Skid Sprayer |
| Fertilizer Carrier | Often pre-mixed on clay/limestone carrier | Tank-mixed with liquid nitrogen (e.g., UAN 28%) |
| Estimated Cost (per 1k sq ft) | $0.12 - $0.18 | $0.04 - $0.08 |
For homeowners and prosumers, the 0.48% Granular is highly accessible and easy to calibrate. For commercial operators or advanced turf managers, the 65 WDG offers massive cost savings and allows for precise tank-mixing with liquid fertilizers and surfactants.
Pairing Barricade with Spring Fertilizer Programs
A common mistake in spring lawn care is applying a high-nitrogen, quick-release fertilizer simultaneously with a pre-emergent. Pushing aggressive top-growth in early spring depletes the turf's carbohydrate reserves right before the stress of summer heat. Furthermore, heavy irrigation required to water in granular fertilizer can sometimes move the pre-emergent barrier too deep if not calibrated correctly.
The Ideal Spring Nutrient Profile
When pairing a spring fertilizer with your Andersons Barricade application, look for an N-P-K ratio that emphasizes slow-release nitrogen and potassium for root development. A 20-0-5 or 15-0-15 blend is optimal.
- Nitrogen Source: Ensure at least 50% to 75% of the nitrogen is slow-release (Methylene Urea, Sulfur-Coated Urea, or Poly-Coated Urea). This provides a steady 6-to-8-week feed without causing a massive growth flush that requires frequent mowing.
- Application Rate: Target 0.5 to 0.75 lbs of actual Nitrogen per 1,000 sq ft. If using a 20-0-5 fertilizer, apply 3.5 lbs of product per 1,000 sq ft to hit this target.
- Phosphorus Warning: Avoid 'Starter Fertilizers' (high in phosphorus, e.g., 10-18-10) unless you are overseeding. Phosphorus promotes seedling growth, which is counterproductive when you are actively trying to prevent weed seeds from germinating. Note: You cannot overseed if you have applied Barricade, as it will kill grass seed.
Step-by-Step Spring Application Protocol
Timing is dictated by soil biology, not the calendar. According to turfgrass researchers at NC State TurfFiles, crabgrass germination initiates when soil temperatures at a 2-inch depth reach 50°F to 55°F for three to five consecutive days.
- Monitor Soil Temperatures: Use a digital soil probe thermometer or track local data via the GreenCast Online soil temperature maps. Do not rely on ambient air temperature.
- Prepare the Turf: Mow the lawn slightly lower than your target summer height and rake away heavy thatch. Thatch exceeding 0.5 inches will intercept the granular Barricade, preventing it from reaching the soil surface where the barrier must form.
- Calibrate Equipment: Weigh out your Andersons Barricade 0.48% (target 2.5 lbs/1,000 sq ft for average soils) and your slow-release fertilizer. Calibrate your spreader on a concrete driveway to ensure an even spread pattern before hitting the grass.
- Broadcast Application: Apply the pre-emergent and fertilizer in perpendicular passes (north-south, then east-west) to avoid striping and missed spots.
- Watering In: Prodiamine requires 0.25 to 0.5 inches of irrigation or rainfall within 7 days of application to dissolve and bind to the soil particles. Without this activation, UV degradation will break down the chemical on the surface.
Troubleshooting: When Pre-Emergent and Nutrition Clash
Even with perfect timing, turf managers encounter failure modes when combining herbicide and nutrition protocols.
Failure Mode 1: Core Aeration Post-Application
Core aeration physically breaks the chemical barrier at the soil surface, bringing untreated soil to the top and allowing weed seeds to germinate in the aeration holes. Solution: Always core aerify in the fall, or aerify in early spring before the Barricade application. If you must aerate in late spring, plan a second, half-rate split application of pre-emergent to repair the barrier.
Core aeration physically breaks the chemical barrier at the soil surface, bringing untreated soil to the top and allowing weed seeds to germinate in the aeration holes. Solution: Always core aerify in the fall, or aerify in early spring before the Barricade application. If you must aerate in late spring, plan a second, half-rate split application of pre-emergent to repair the barrier.
Failure Mode 2: Microbial Degradation
Applying pre-emergent too early (e.g., February in transition zones) exposes the prodiamine to soil microbes for a longer period before weed seeds actually germinate. High-nitrogen fertilizers stimulate these same soil microbes, potentially accelerating the breakdown of the herbicide. Solution: Utilize a split-application strategy. Apply 60% of your total seasonal Barricade rate in early spring, and the remaining 40% eight weeks later to extend the barrier into late summer.
Applying pre-emergent too early (e.g., February in transition zones) exposes the prodiamine to soil microbes for a longer period before weed seeds actually germinate. High-nitrogen fertilizers stimulate these same soil microbes, potentially accelerating the breakdown of the herbicide. Solution: Utilize a split-application strategy. Apply 60% of your total seasonal Barricade rate in early spring, and the remaining 40% eight weeks later to extend the barrier into late summer.
Frequently Asked Questions
Can I tank-mix liquid Barricade 65 WDG with liquid iron or micronutrients?
Yes. Barricade 65 WDG is highly compatible in tank mixes. Many turf managers mix it with chelated iron (Fe-EDDHA) and liquid kelp to provide a spring micronutrient boost and deepen turf color without pushing excessive vegetative growth. Always perform a jar test first to ensure the specific liquid fertilizer does not cause the WDG to flocculate or settle out in the tank.
Does high soil pH affect Andersons Barricade efficacy?
Unlike some herbicides (like 2,4-D or glyphosate) which can be antagonized by high pH or hard water in the spray tank, prodiamine's soil efficacy is largely unaffected by soil pH levels between 5.5 and 7.5. Its primary limiting factor is soil organic matter and clay content, not pH. However, your fertilizer program should be adjusted based on pH; if your soil pH is above 7.2, switch to ammonium sulfate-based nitrogen sources to help lower the rhizosphere pH and improve nutrient availability.
How long must I wait to seed my lawn after applying this pre-emergent?
Prodiamine creates a long-lasting barrier. According to University of Minnesota Extension turfgrass guidelines, you must wait a minimum of 4 to 6 months after a standard spring application before sowing new grass seed. For most regions, a spring application means you cannot overseed until early autumn. If you must repair bare spots in the summer, use sod instead of seed, as mature sod roots can penetrate the pre-emergent barrier without being killed.
