Diagnostic Help Desk

As of August 15th, 2025, the Jefferson County Diagnostic Help Desk is closed for the season and
no longer taking samples. CSU SPUR is still available for any diagnostic needs. The CSU SPUR
campus is in Denver at the Terra Building at 4780 National Western Drive Denver CO 80216
Phone: 970.491.6950
Email: csuplantlab@colostate.edu
Website: https://agsci.colostate.edu/agbio/plantclinic/

Do you have a horticulture question? Reach out to our Master Gardeners! For the quickest response, please send an email to mastergardener@jeffco.us
If calling is preferred, please reach out to the main CSU Extension line at (303)271-6620

Soil testing services are provided only through the CSU state lab. Jefferson County no longer provides testing kits. Please place your soil in a plastic or waterproof paper bag. Once you have filled out and printed your submittal form, include it with your sample and mail or deliver to: CSU Spur Soil, Water and Plant, Testing Lab, Room T-316 / 4780 National Western Drive / Denver, CO 80216. Visit the state website here for more information.

Educational Outreach

Are you interested in having our Horticulture Specialist or Master Gardeners come teach on a topic or lead a workshop? Fill out our contact form, here – Jefferson County Horticulture Request Form (qualtrics.com)

Online Resources

Online Publications – CSU Extension is chock-full of online publications related to all things horticulture, not limited to topics such as: Vegetables and Herbs, Trees and Shrubs, Water-wise Landscaping/Xeriscaping, and Soils. Publications vary in level of detail – PlantTalk‘s provide the simplest level of detail, whereas GardenNotes and Fact Sheets provide more in-depth information. Feel free to explore the various publications that we offer!

Ask an Expert – Get personalized answers to your horticultural questions from Cooperative Extension staff and volunteers across the country. For Colorado specific questions, you can ask a question here – Extension: Ask an Expert