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Ask a Master Gardener

Master Gardeners are University of California trained and certified volunteers. Our Helpline is a free public service  available to assist home gardeners from San Mateo and San Francisco Counties with questions about home horticulture and pest management. Master Gardener volunteers staff our Helpline on Mondays and Thursdays from 9am to 4pm, and Wednesdays from 10:30am to 2pm. (We are closed on holidays.)

Call us: 650-276-7430 

Email us: mgsmsf@ucanr.edu

Please provide the following information to facilitate a prompt response:

  1. Name
  2. City of Residence
  3. Email
  4. Phone, Best time to call
  5. Description of Problem/Question* 

*For plant or pest problems, please attach photo(s).

  • For plant problems, include:
    • what the damage looks like
    • when symptoms first appeared
    • where is the plant located
    • age of plant
  • For pest problems, include:
    • what & where the damage is occurring
    • extent of the damage (how widely spread)
    • when symptoms first appeared
  • What care has the plant received?
    • Irrigation: Drip/Sprinkler/Hand/Flood. How often?  How long?
    • Fertilizer: What type? How often? Last applied?
    • Chemical applications, if any (herbicides and/or pesticides)

Visit us: You are welcome to visit one of our offices to consult with us during Helpline hours. Please bring your plant or pest problems with you in a sealed bag or container - except to the San Francisco Botanical Garden location where they are not allowed!



Mondays 9-am - 4pm Wednesdays 10:30 am - 2pm Thursdays 9am - 4pm
at UC Elkus Ranch
in the Conference Center

1500 Purisima Creek Road
Half Moon Bay
Google map / Directions

San Francisco Botanical 
Garden (SFBG) Library
1199 9th Avenue
San Francisco, CA 94122 Google map / Directions

*Please do not bring any plant samples to the SF helpline location.

Veterans Memorial Senior Center (VMSC)
1455 Madison Ave.
Redwood City 
Google map

 We also hold regular Plant Clinics in various places in San Mateo and San Francisco Counties. Check our Calendar for locations and dates.