Lesson 4: Irrigation Part I

Please note, class was not recorded on February 15. This presentation of Lesson 4 is from a previous cohort with instructor Nicole Calhoun.

  1. Learning objectives
    1. Define a garden’s irrigation needs: age of garden, plant material, irrigation system, and soil type
    2. Schedule irrigation to mimic typical seasonal rainfall
    3. Change irrigation as a garden matures
  2. Homework review
    1. Infiltration – Results? Discuss implications and how soils are tied to horticultural problems.
    2. What type of soils did you find?
    3. What was the infiltration rate?
  3. Discussion: Factors influencing irrigation needs
    1. Abiotic versus biotic factors
      1. Wind, sunlight, heat, soil texture, and exposure
      2. Plant water uptake, age of plants, canopy coverage, soil organic matter
  4. Discussion: Irrigate to mimic typical seasonal rainfall for a given area
    1. In southern California our typical rainfall averages around 15” a year, strive to achieve this level of precipitation every fall through spring
  5. Discussion: Delivery systems
    1. Drip versus overhead, benefits and drawbacks
  6. Discussion: How much to water
  7. Discussion: Change irrigation as a garden matures
  8. In-class exercises: Determining irrigation frequency | Sharing personal experiences with irrigation
  9. Resources
    1. Manufactures
      1. Rainbird
      2. Hunter Industries
      3. Netafimusa
    1. Local/Online Suppliers
      1. Ewing Irrigation & Landscape Supply
      2. Landscape Warehouse Irrigation Supplies & Nursery
      3. Aqua-Flo Supply
      4. DripWorks
      5. The Drip Store
    1. Tutorials/Guides
      1. Hunter Drip Irrigation Design & Installation Guide
      2. Landscape Watering by The Numbers
      3. The River Project.org: Water Resources Page
      4. Tree of Life Nursery: Watering Native Plants
      5. WUCOLS Landscape Water-Use Planning Tool (English)
      6. SoCal Water$mart Residential Rebates (English)

      7. SoCal Water$mart Residential Rebates (Spanish)

  10. Homework
    1. Field irrigation analysis”-Evaluate an irrigation system being used on a native plant landscape that you see being used at home, in a botanic garden, in your neighborhood, or at a worksite. What is being used? Assess the plant material, weeds present, overall health and vigor, spacing, distribution, etc. Send your findings to your instructor via email.  

                                                     i.     Public gardens/institutions with native plant landscapes open to public

      1.    Theodore Payne Foundation for Wildflowers and Native Plants

      2.    Santa Barbara Botanic Garden

      3.    Channel Island Visitor Center

      4.    Santa Ynez Valley Botanic Garden

      5.    Ventura Botanical Gardens

      6.    UCSB, North Campus Open Space

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