Can You Mix MSMA and 2,4-D? Complete Safety Guide 2024

Understanding MSMA and 2,4-D Herbicides

Both MSMA (monosodium methanearsonate) and 2,4-D (2,4-dichlorophenoxyacetic acid) are post-emergent herbicides used for controlling broadleaf weeds and some grassy weeds in established warm-season turf.

MSMA (Monosodium Methanearsonate)

• Primary Use: Controls grassy weeds like crabgrass, dallisgrass, and johnsongrass
• Action: Contact herbicide that causes rapid desiccation
• Safe on: Bermuda grass, Zoysia grass (established turf only)
• Temperature sensitivity: Most effective in warm weather (75-85°F)

2,4-D (2,4-Dichlorophenoxyacetic acid)

• Primary Use: Controls broadleaf weeds like dandelions, clover, and plantain
• Action: Systemic herbicide that disrupts plant growth hormones
• Safe on: Most established grasses when used properly
• Temperature sensitivity: Effective in moderate temperatures (60-80°F)

Can You Mix MSMA and 2,4-D? The Answer

Yes, MSMA and 2,4-D can be mixed together for tank mix applications, but several important factors must be considered:

Compatibility Factors

• Chemical Compatibility: Both are water-soluble and generally compatible
• pH Requirements: Both work best in slightly acidic to neutral pH
• Temperature Requirements: Overlapping effective temperature ranges
• Grass Safety: Both are safe on established warm-season grasses

Benefits of Tank Mixing

• Broad Spectrum Control: Targets both grassy and broadleaf weeds
• Reduced Applications: One application instead of two separate treatments
• Cost Efficiency: Lower labor and fuel costs
• Timing Efficiency: Single application window

Proper Mixing Ratios and Rates

Standard Tank Mix Ratios

For 1,000 square feet:

• MSMA: 1-2 fluid ounces (follow label rates)
• 2,4-D: 0.5-1 fluid ounce (follow label rates)
• Water: 1-2 gallons (depending on sprayer type)

For 1 acre (43,560 sq ft):

• MSMA: 2-4 pints (check label for specific rate)
• 2,4-D: 1-2 pints (check label for specific rate)
• Water: 20-40 gallons

Mixing Order (Critical for Success)

1. Fill tank 1/3 with water
2. Add 2,4-D first while agitating
3. Add MSMA second while continuing agitation
4. Fill to final volume with water
5. Maintain agitation throughout application

Application Timing and Conditions

Optimal Weather Conditions

• Temperature: 70-80°F for best results
• Wind: Less than 10 mph to prevent drift
• Humidity: Moderate humidity (40-70%)
• Rain: No rain expected for 4-6 hours after application
• Time of Day: Early morning or late afternoon

Seasonal Timing

Best Application Periods:

• Spring: Late April through May (active weed growth)
• Summer: Early to mid-summer before extreme heat
• Fall: Early fall for perennial weed control

Avoid Application During:

• Extreme heat (above 85°F)
• Drought stress conditions
• Newly seeded or sodded areas (wait 6-8 weeks)
• Windy conditions (drift potential)

Target Weeds for MSMA + 2,4-D Mix

Grassy Weeds (Primarily MSMA target)

• Crabgrass: Large and smooth varieties
• Dallisgrass: Difficult perennial grass weed
• Johnsongrass: Tall, aggressive grass weed
• Sandbur: Spiny seed pods
• Goosegrass: Flat growth pattern

Broadleaf Weeds (Primarily 2,4-D target)

• Dandelion: Deep taproot perennial
• Clover: White and red varieties
• Plantain: Broad and narrow leaf types
• Chickweed: Cool season annual
• Henbit: Square stem broadleaf

Mixed Infestations

The combination is particularly effective for:

• Lawns with both grassy and broadleaf weed problems
• Transitional areas with diverse weed populations
• Neglected turf with established weed communities

Safety Precautions and PPE

Required Personal Protective Equipment

• Chemical-resistant gloves: Nitrile or butyl rubber
• Long sleeves and pants: Chemical-resistant material preferred
• Eye protection: Safety glasses or goggles
• Footwear: Chemical-resistant boots
• Respirator: When label requires or in enclosed areas

Mixing Safety Protocol

1. Read all labels completely before starting
2. Work in well-ventilated area or outdoors
3. Measure chemicals carefully using proper measuring tools
4. Never eat, drink, or smoke while handling
5. Keep children and pets away during mixing and application
6. Have water available for emergency eye/skin flushing

Application Safety

• Check wind direction: Apply upwind from sensitive plants
• Mark treated areas: Prevent accidental exposure
• Clean equipment thoroughly after use
• Store unused mix properly or dispose according to label

Grass Safety and Phytotoxicity

Safe Grass Types

Established warm-season grasses (6+ weeks old):

• Bermuda grass: High tolerance to both chemicals
• Zoysia grass: Good tolerance when established
• St. Augustine: Moderate tolerance (test small area first)
• Centipede: Use with caution, lower rates

Sensitive Grass Types (Avoid)

• Cool-season grasses: Fescue, bluegrass, ryegrass
• Newly seeded areas: Wait 8-12 weeks
• Newly sodded areas: Wait 6-8 weeks minimum
• Stressed turf: Drought, disease, or heat stress

Signs of Phytotoxicity

Watch for these symptoms in the days following application:

• Yellowing or browning of grass tips
• Stunted growth or twisted leaves
• Irregular brown spots in treated areas
• Growth distortion or abnormal leaf shape

Legal and Regulatory Considerations

MSMA Restrictions

• EPA Status: Limited registration, some uses canceled
• State Restrictions: Varies by state - check local laws
• Professional Use: Some areas restrict to licensed applicators
• Groundwater Protection: Restricted in sensitive watersheds

2,4-D Considerations

• Drift Concerns: Strict application requirements
• Buffer Zones: Distance requirements from sensitive areas
• Endangered Species: Special restrictions in critical habitats
• Pollinator Protection: Avoid application during bloom periods

Alternative Approaches

Sequential Applications

Instead of tank mixing, consider applying separately:

• Week 1: Apply 2,4-D for broadleaf weeds
• Week 3-4: Apply MSMA for grassy weeds
• Benefits: Reduced phytotoxicity risk, targeted timing

Pre-Mixed Products

Commercial products containing both active ingredients:

• Advantages: Pre-tested compatibility, consistent ratios
• Disadvantages: Less flexibility in rates
• Availability: Limited due to MSMA restrictions

Alternative Herbicide Combinations

• 2,4-D + MCPA: Broadleaf weed control
• Quinclorac + 2,4-D: Crabgrass and broadleaf control
• Three-way mixes: 2,4-D + MCPP + Dicamba

Application Equipment and Calibration

Recommended Equipment

• Pump Sprayer: 1-4 gallon capacity for small areas
• Boom Sprayer: Tractor-mounted for large areas
• ATV Sprayer: Good for medium-sized properties
• Backpack Sprayer: Precision application capability

Nozzle Selection

• Flat Fan Nozzles: Even coverage, good for broadcast
• Low-drift nozzles: Reduce drift potential
• Avoid: Hollow cone nozzles (too fine droplets)

Calibration Steps

1. Measure application area accurately
2. Test water output over known area
3. Calculate chemical amounts based on area and rate
4. Test spray pattern with water first
5. Maintain consistent speed during application

Post-Application Care

Immediate Care (First 24 hours)

• No watering: Allow chemicals to absorb
• No traffic: Keep people and pets off treated area
• No mowing: Wait 3-5 days minimum
• Monitor weather: Watch for unexpected rain

Follow-up Care (Days 2-14)

• Light watering: If no rain within 48 hours
• Observe results: Weeds should show effects in 3-7 days
• Document results: Note effectiveness for future reference
• Plan follow-up: Some weeds may need repeat treatment

Troubleshooting Common Issues

Poor Weed Control

Possible Causes and Solutions:

• Too low rate: Check label rates, increase if appropriate
• Poor coverage: Improve calibration and spray technique
• Wrong timing: Apply when weeds are actively growing
• Resistant weeds: Consider alternative herbicides

Grass Injury

Possible Causes and Solutions:

• Too high rate: Follow label rates exactly
• Hot weather: Apply during cooler conditions
• Stressed turf: Wait for grass recovery before treating
• Wrong grass type: Verify herbicide safety

Professional vs. DIY Application

Consider Professional Application If:

• Large area: Over 1 acre treatment
• Valuable landscape: High-end turf areas
• Complex weed problems: Multiple resistant species
• Limited experience: First time using these chemicals
• Equipment needs: Lack proper application equipment
• Legal requirements: Local laws require professional application

DIY Application Considerations

• Start small: Test on inconspicuous area first
• Follow labels exactly: Never exceed recommended rates
• Proper disposal: Leftover chemicals and containers
• Record keeping: Document what, when, and where applied

Environmental Considerations

Water Protection

• Buffer zones: Maintain distance from water bodies
• Slope considerations: Avoid application on steep slopes
• Soil type: Sandy soils have higher leaching potential
• Timing: Avoid application before heavy rain

Beneficial Insects

• Pollinator protection: Avoid application during flowering
• Beneficial predators: Consider impact on pest control insects
• Soil organisms: Monitor for effects on soil biology

Conclusion and Best Practices

Key Takeaways:

• MSMA and 2,4-D can be successfully tank mixed when done properly
• Always follow label rates and never exceed recommendations
• Proper timing and weather conditions are crucial for success
• Safety equipment and procedures are non-negotiable
• Check local regulations before purchase or use
• Consider professional application for valuable turf areas