Weed Management

Western Sustainable Agriculture Research & Education
(SARE) Farm Internship Curriculum and Handbook


Published 2007
Updated 2010


Weed Management

Pre-Assessment Questions

  • What is a weed?
  • How are weeds dispersed?
  • What are some benefits of weeds in a cropping system?
  • What are some of the characteristics of weeds that allow them to compete so well in cropping systems?
  • Why control weeds?


Definition – What is a weed?
A weed is any plant, native or non-native, that interferes with crop production by doing more harm than good and has a habit of encroaching where it is not wanted.


Weed Problems

  • Crop competition and its effect on crop yield and quality
  • Nutrient competition
  • Light competition
  • Water competition
  • Interference with harvesting operations
  • Example: Weed roots such as bindweed wrap around sub-soil blades used for undercutting root crops during harvest


Weed Benefits

  • Enhance soil structure
  • Improve soil tilth
  • Cycle nutrients
  • Provide habitat for beneficial insects
  • Improve soil water infiltration


Weed Prevention Strategies

  • Improve soil tilth, aeration, water infiltration, and fertility to optimize crop growth and minimize weed pressure
  • Thoroughly clean equipment before moving it from one farm or location to another
  • Do not allow weeds to form seed heads and/or perennial rooting structures in the cropping system
  • Thoroughly compost all imported animal manures to insure destruction of viable weed seed
  • Filter surface irrigation water to avoid importing weed seeds
  • Work with neighbors to eliminate or minimize the potential for spread of noxious and problematic weeds from adjacent lands



  • Tour fields and identify most common weeds (star thistle, pigweed, purslane, chicory, wild lettuce, grasses, etc.)
  • Pull or dig selected weeds and examine root system


Management through Manual Cultivation

  • Demonstrate and practice proper techniques with various tools – wheel hoe, stirrup hoe, collinear hoe, and Mexican hoe. Discuss need for follow-up cultivation.
    • Benefits – eliminates weeds, stirs soil and breaks crust (allows for easier penetration of air and water)


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This page was last updated on: August 25, 2014