Low%20Impact%20Weed%20Control%20Mulches

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Low Impact Weed ControlMulches

• Cheryl Wilen
• Area IPM Advisor
• UCCE/UC IPM

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Stages for Weed Management

• Planning
• Prevention
• Control
• Restoration

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Questions About Landscape Mulches
What is a mulch?
Is mulch the same as compost?
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Mulch

• A material that covers the soil surface.
• Shades the ground and physically hinders
  germinating weed seedlings.
• Mechanical method of weed management

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How to Choose
Characteristics
Selection of a specific mulch

• Non toxic to plants
• Easy to apply
• Free from pathogens and weed seed
• Not a nitrogen drain

• Availability
• Cost
• How often it needs to be replenished

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LOTS OF CHOICES!!

• Natural

• Synthetic

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http//www.gardenplace.com/content/calculator/mulc
h_calc.html Search Mulch calculator
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Is Mulch the Same as Compost?
Mulch is a use. Compost is a process.
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Benefits of Landscape Mulch

• Annual weed control
• Soil improvement
• Prevents erosion
• Helps improve soil structure
• Improves water infiltration
• Prevents water loss by evaporation

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Soil ImprovementErosion Control

• A thin layer of mulch on the soil surface reduces
  the washing away of soil particles by rushing
  water.
• Mulches prevents raindrops from splashing on the
  soil surface.
• Increases organic matter from breakdown
• A mulch layer on the soil surface allows the soil
  to soak up more water.

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Evaporation Reduction

• A 3-inch layer of mulch on the soil surface dries
  much faster than the soil below it
• This prevents water from moving into air.

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Breakdown

• A 3-inch layer of mulch on the soil surface keeps
  most annual weed seedlings from coming through.
• Mulch settles and gradually rots
• Add additional layers

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DISADVANTAGES OF MULCHING

• Some mulches can cause a temporary, decrease in
  soil nitrogen
• Some mulching practices are labor intensive
• Bad mulches are sour and phytotoxic
• May have insects, pathogens
• No perennial weed control

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More Better
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Whats that growing in my mulch?
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Termites
Would subterranean termites eat mulch?

• Mulch provides better habitat than food
• Should keep mulch about 18 away from wood
  structures

Would subterranean termites survive on mulch?
Note probably not an issue for drywood termites
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Fabric Mulches

• Fabric thickness affects the degree of weed
  suppression.
• Prevents light penetration.

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Rose Vigor(approx. 5 months after transplanting)
0dead, 10highly vigorous
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Agricultural Mulch
Plastic Films

• Basic colors used (black, green, red)
• Black
• Most widely used
• Usually embossed for strength
• Cheapest
• Warms soil by contact

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Rubber Mulch - a "permanent" mulch that doesn't
rot, dissolve into the ground or wash away from
rain. Made from recycled rubber truck tires,
lasting ten years
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PHYSICAL CONTROL OF PESTS USE OF MULCHES
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• MULCHES MAY BE USED TO
• MANIPULATE TEMPERATURE
• MANIPULATE LIGHT
• MANIPULATE SOIL MOISTURE
• OTHER EFFECTS

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• REDUCE INSECT FEEDING DAMAGE AND TRANSMISSION OF
  DISEASES USING
• REFLECTIVE MULCH

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• MODES OF ACTION
• Light reflection
• Other?

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Insect Feeding Behavior
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