What Pre-Emergent Does
Pre-emergent herbicides are used to prevent weeds before they emerge. They work by creating a chemical barrier in the soil that stops newly germinating weed seeds from establishing roots. Pre-emergents do not kill existing weeds. Once a weed is visible, post-emergent control is required.
Pre-emergents must be watered into the soil to activate. Without rainfall or irrigation, the barrier never forms and the application fails. This is why pre-emergents are often called “yellow herbicides” they go down first, quietly do the work underground, and only succeed if moisture moves them into the soil profile.
Timing Matters More Than Product
In West Texas, timing is driven by soil temperature, not the calendar. That said, for simplicity and consistency, our recommended application windows are:
-
February spring pre-emergent
-
May late spring / extended control
-
September fall pre-emergent
These windows line up with weed germination patterns and turf growth in our area.
Soil Temperature & Weed Germination
Below 55°F
-
Winter annual weeds germinate
-
Examples: henbit, chickweed, annual bluegrass
Above 55°F
-
Summer annual weeds begin germination
-
Examples: crabgrass, goosegrass
Around 65°F
-
Bermuda grass begins active growth and germination
Above 75°F
-
Late summer annual weeds germinate
-
Heavier pressure and faster growth
Think of soil temperature as a switch. Once that switch flips, the pre-emergent window is closing or already closed.
One Key Reminder
Pre-emergent applications must be watered in with rainfall or irrigation. No water means no barrier. No barrier means weeds.
GRANULAR PRE-EMERGENT PRODUCTS
Andersons 11-3-11 w/ 0.86% Pendimethalin
-
Form: Granular fertilizer + herbicide
-
Rate: 5 lb per 1,000 sq ft
-
Coverage: 10,000 sq ft per 50 lb bag
-
Timing: Spring and fall
-
Strength: Broad annual grass control
-
Notes: Most popular all-around turf program
Pendimethalin 2G
-
Form: Granular herbicide only
-
Rate: 3 lb per 1,000 sq ft
-
Coverage: 13,000 sq ft per 40 lb bag
-
Timing: Spring and fall
-
Strength: Clean pre without fertilizer
-
Notes: Use when fertility is not needed
6-3-12 w/ 0.37% Prodiamine
-
Form: Granular fertilizer + herbicide
-
Carrier: Hu-Actinite
-
Rate: 6.25 lb per 1,000 sq ft
-
Coverage: 8,000 sq ft per bag
-
Timing: Early spring or fall
-
Strength: Long residual control
-
Notes: Stronger hold than pendimethalin
LIQUID PRE-EMERGENT PRODUCTS
Prodiamine 65 WDG (Quali-Pro)
-
Form: Water-dispersible granule
-
Rate:
-
0.38 oz per 1,000 sq ft (lighter pressure)
-
0.55 oz per 1,000 sq ft (heavy pressure)
-
-
Timing: Early spring or fall
-
Strength: Longest residual
-
Notes: Commercial backbone product
Pendimethalin HydroCap
-
Form: Liquid micro-encapsulated
-
Rate:
-
0.55–1.1 oz per 1,000 sq ft
-
-
Timing: Spring or fall
-
Strength: Consistent soil binding
-
Notes: Good alternative to granular programs
PROFESSIONAL-GRADE ADDITIONS
Barricade 4FL (Prodiamine)
-
Form: Liquid
-
Rate: 0.38 - 0.55 oz per 1,000 sq ft
-
Use: Large acreage, commercial turf
-
Strength: Long residual, flexible application
Dimension (Dithiopyr)
-
Form: Granular or liquid
-
Rate: Per formulation
-
Use: Slightly late applications
-
Strength: Early post-emergent activity on crabgrass
-
Notes: Shorter residual than prodiamine
Indaziflam (Esplanade / Specticle)
-
Form: Liquid or granular
-
Rate: Extremely low use rates (label specific)
-
Use: High-pressure commercial sites
-
Strength: Longest residual available
-
Notes: Not for casual homeowner use
Activation & Irrigation
-
Apply ½ - 1 inch of water within 7 - 10 days.
-
Rainfall can substitute if sufficient.
-
Do not mechanically disturb soil after application.
Common Mistakes
-
Applying after weeds are visible.
-
Skipping irrigation.
-
Using pre-emergent on newly seeded turf.
-
Overlapping applications causing root pruning.
Print Friendly