About the
Colorado Master Gardener Program

Thinking about becoming a Colorado Master Gardener? View the video below.

What is a Colorado Master Gardener (CMG)?

Colorado Master Gardeners (CMG) are adult volunteers trained in horticulture by Colorado State University Extension staff.

What do Colorado Master Gardeners do?

They assist Colorado State University Extension staff in delivering research-based gardening information to foster successful gardening in Colorado communities.

The CMG Volunteer's audience is exclusively home gardeners. Types of volunteer service include answering phone calls at county Extension offices, staffing diagnostic clinics, teaching gardening classes, writing newspaper and web articles and mentoring community gardening and greening projects. Click here for additional details about CMG activities in specific Colorado counties.

What are the benefits of being a Colorado Master Gardener?

  • 60 hours of horticulture training from subject matter specialists
  • Access to continuing education classes and webinars
  • Educating your communities with research based information and relevant options
  • Become part of a group with shared interests
  • Develop new friendships

Colorado Master Gardeners

When and where is the training offered?

Yearly training for apprentice Colorado Master Gardeners (trainees) is offered from January through late March or early April of each year. Classes generally meet once per week from 9 am to 4 pm with an hour for lunch.

Classes are held in multi-county sites for counties along the Front Range corridor (Adams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver, Douglas, Elbert, El Paso, Gilpin, Jefferson, Larimer, and Weld Counties) and the Tri River Area (Mesa, Delta, Montrose and Ouray Counties).

In other counties, some of the training is offered via distance education at the local county Extension office. Counties participating in the distance education course include Archuleta, Chaffee, Eagle, Fremont, Garfield, Golden Plains Area (Kit Carson, Phillips, Washington, and Yuma), Grand, Gunnison, La Plata, Montezuma, Morgan, Pueblo, Routt, San Miguel and West Montrose Area, San Luis Valley, Summit and Teller.

A group of northern metro counties offer an evening course on Tuesdays and Thursday, from 6 to 9 p.m., in the fall (mid-September to early December). Students from neighboring counties may also participate in the evening class (depending on space available) by first contacting their home county for availability and then applying through their home county. Inquiries should be made in early summer prior to the start of class.

What does the course cover?

Curriculum content is focused on the home gardener (non-commercial) audience. The curriculum includes a combination of lecture and on-line segments interspersed with small group discussions and lab-type activities.

Responding to local needs, topics covered in the basic training vary somewhat from location to location and from year to year. Refer to a schedule for specifics for any location. As space allows, CMG volunteers have the option to attend additional classes in future years as continuing education. Curriculum units include the following:

  • Botany - This basic class covers plant structures and growth factors. Presented with lecture and hands-on activities, the class objective is to help students develop skills to examine plants close-up and relate observations with plant disorders. (6 hour class)

  • Master Gardener diagnosingDiagnosing Tree Disorders - This class expands on the content covered in the Diagnostics and PHC class.

    After reviewing the diagnostic process, student practice diagnosing common tree pests in a lab-type activity. In small group work, students practice developing management recommendations for common pest problems. (3 hour class) While many real-life samples will not be as straightforward as the examples used in class, it gives students experience with the process and confidence in their abilities.

  • Herbaceous Plants (Flowers): Right Plant, Right Place - Hot, dry and windy, clayey or rocky soils and short growing seasons are just some of the challenges faced by the Colorado gardener. Few catalog or plant descriptions directly apply to the unique growing conditions found in Colorado’s high plains or mountain communities. This class looks at interpreting catalog and plant description for Colorado growing conditions, putting the right flower in the right place. (3 hour class)


  • Master Gardener identifying plantsIdentifying Trees and Shrubs - This class expands concepts learned in Botany, enhancing skills in identifying trees and shrubs. Through lecture and hands-on labs, students practice plant identification using evergreen and deciduous trees and shrubs.


  • Introduction to Entomology - This class introduces students to the fascinating world of insects and insect management. (6 hour class).



  • IPM and the Diagnostic Process - This class introduced the concepts of IPM: Plant Health Care (central theme through the entire course) and the diagnostic process. (3 hour class) IPM and diagnostics


  • Lawn Care - Turfgrass Management - This class covers basic lawn care issues faced by home gardeners and lawn diagnostics. (3 or 6 hour class, depending on location)

Mountain Gardening
  • Mountain Gardening - Mountain gardening has all of the challenges of gardening in Colorado (poor soils, wind and heat, water restrictions, etc.) with the addition of several others. These include a shorter growing season, cooler nights, wildlife and a smaller plant palette. This class looks at how to work with the challenges of gardening at higher elevations. (3 or 6 hour class, depending on location)


  • Pruning - This class covers pruning basics including basic cuts, structural pruning of young shade trees and pruning options to keep shrubs natural looking. (6 hour class)
      • Basic pruning cuts
      • Structural pruning of young shades tree – Typical wind and snow load damage can be minimized with structural pruning while the trees are young. Structural pruning is easy for the home gardener to understand and do.
      • Pruning of mature trees is the job for a certified and bonded arborist. This class looks at the concepts the professional uses in pruning mature tree so the gardener will understand options and work to be done.
      • Pruning options to keep shrubs natural looking.


  • Small Fruits - Small fruits are easy for the home gardener to grow. The class reviews techniques and common pitfalls with home production of small fruits. (3 hour class)


  • Soils, Fertilizers and Soil Amendments - Many landscape plant problems relate back to soil and root conditions. Content includes soil management, soil amendments and fertilizers. (6 hour class)

  • Tree Fruit - Tree fruits are challenging for the home gardener due to insect problems, spring frost and annual pruning requirements. Class reviews the techniques and common pitfalls with home tree fruit production. (3 hour class)

  • Planting treeTree Planting: Right Plant Right Place - The average life of a tree in the landscape is only eight years and is often due to planting problems. This class examines proper tree selection and planting techniques to enable a long and healthy life for landscape trees. (3 hour class)


  • Raised bedsVegetables - This class focuses on techniques to maximize yields and quality of home grown produce. Topics include soil preparation and fertilization, raised bed gardening, garden layout, irrigation, mulches and frost protection. (3 or 6 hour class, depending on location)


  • water wise landscapingWater Wise Landscape Design - This class has direct application for the new landscape and for the gardener wishing to make an existing landscape more water efficient. The class introduces landscape design as a process, including the following key points: (6 hours)
      • Opportunities and challenges from site analysis.
      • Connecting the family to the landscape with a landscape storyline.
      • Use of line to define and connect outdoor rooms.
      • Hydrozone layouts, the foundation of water savings.
      • Basic layout with rectilinear, curvilinear and angular design style.
      • Adjusting primary lines for efficient irrigation.
      • Techniques to apply balance, scale, sequence and variety to color, texture and form.
  • Techniques to make pleasing plant combinations.

  • Weed Management - Weeds are a common frustration for gardeners. This class addresses basic weed management techniques for the home garden and landscape. (3 or 6 hour class, depending on location)

  • Local CMG Orientation - In addition to the basic classes, CMG volunteers will have a local orientation covering county- specific volunteer opportunities.

CMG Volunteers are required to attend at least 80% of the class sessions. Students should plan on attending all of the classes. However, that is not always possible due to illness, family emergencies, and weather-related travel issues.  When missing a class, the student is responsible for the content and should invest extra time with the study materials. Many of the lecture units are also available 24/7 online.>

How much does it cost?

In 2017, the fee was $170. Limited income scholarships may be available for an $85 fee. Check with your local county.

CMG Book

Is there a book?

All the written materials you need are in our CMG GardenNotes and can be read on-line or downloaded onto your device from the Colorado Master Gardener web site. Additional class materials may be distributed by the instructor, depending on the course.

How do I become a Colorado Master Gardener?

Because the applicant needs county specific information regarding the CMG program, applications are NOT available on-line. Contact your local CSU Extension County Office.

Applicants should apply to their home county. CMG programs operate at the county level, with primary support from the county government. In special situations a potential volunteer may apply to a neighboring county. However, it should be understood that most county programs give priority to county residents, being responsive to the local county budget and local taxpayers. Applicants who apply to multiple counties will not be considered.

The volunteer work must be completed for the county/area program to which the applicant applied.

Individuals interested in the CMG training from counties that do not offer the CMG Program may apply to a neighboring county under cross-county enrollment and transfer options.

Extension programs are available to all without discrimination. Selection is not based on race, age, color, religion, national origin, gender, disability, sexual orientation, gender identity, or veteran status, disability or handicap.

Students requesting handicap accommodations should directly contact the CSU Resources of Disabled Students Office at 970-491-6385.

Steps to Apply

Step 1 - Contact your local CSU Extension County Office for program information and the application form. County contact information is listed here.

Step 2 - Submit a completed CMG Application Form by the application deadline.

The application form asks for background information on gardening and volunteer experiences, general availability for volunteer work (used by program coordinators to help connect volunteers with projects), criminal background information, contact information for three references, and includes a signed contract committing the CMG volunteer to 50 hours minimum volunteer work in exchange for the training.

  • For the winter training (January-April), applications are processed in the fall of the year. Colorado Front Range Counties have an October 15th application deadline. For other counties, contact your county office for application deadline.


  • For the fall training (September-December) offered in the evening in the northern metro region, applications are processed mid-summer. Contact your county office for availability, application information and deadlines.

Step 3 - Background check – Colorado State University requires background checks, including driver’s license checks, of all new volunteers.  A criminal record or poor driving record does not bar you as a volunteer, but will be considered as it relates to the specifics of the volunteer position. If a potential volunteer elects not to have a background check, they also elect not to become a volunteer for CSU.

Step 4 - Preliminary screening will be based on the application form. Primary considerations include:

  • Interest in volunteer work
  • Availability for volunteer work
  • People skills (i.e., ability to assist Extension in home horticulture educational efforts)
  • Gardening experience

Staff will email confidential reference letters to the references listed on the application. At least two must be returned before the applicant can be accepted into the CMG program.

Step 5 - Interview – Most counties invite applicants in for an informal interview. Some counties may include a written exam in the application process.

Step 6 - Applicants will be advised if they were selected for the CMG Program.  In counties with a larger population base, significantly more people apply than can be accommodated.  Applicants who are not selected as CMG volunteers may enroll under the Colorado Gardener Certificate (non-volunteer) option as space allows.

The decision to accept of not accepting an individual as a volunteer is the right of CSU. To summarize, interested individuals apply to become a Colorado Master Gardener volunteer representing CSU Extension.

The decision to accept or not accept any individual as a volunteer is the right of CSU Extension.  This request can also be withdrawn at any time.

Step 7 - Pay class fees – If accepted into a local CMG Program, payment of class fees is the final enrollment step.

I want to take the course work but I don’t have time to volunteer.

That’s not a problem! Adults interested in taking the CMG training without a volunteer commitment may enroll for the identical coursework under the Colorado Gardener Certificate (CGC) option.  The course work is available for a higher fee in-lieu-of the return service. Individuals who were not selected for the CMG volunteer program may enroll as Colorado Gardener Certificate students as space allows.

Upon completion of the course, Colorado Gardener Certificate students receive the Colorado Gardener Certificate.  However, because there is no subsequent volunteer commitment, participants do not become Colorado Master Gardeners.

To receive the Colorado Gardener Certificate, students must satisfactory complete the CMG/CGC training (i.e., attend at least 80% of the class sessions and complete assigned homework).  Participants are expected to attend all training sessions.  However, that is not always possible due to illness, family emergencies, and weather-related travel issues.  When missing a class, the student is responsible for the content and should invest extra time with the study materials. Most lecture segments are also available 24/7 online. Attendance of the class sessions at another location is not an option.

The Colorado Gardener Certificate may be displayed in a place of business and used in business marketing.

CGC Enrollment - To enroll in the CMG/CGC Training as a Colorado Gardener student (non-volunteer), send in the completed Colorado Gardener Certificate Enrollment Form with the tuition.  Contact your County Extension Office for additional information and the enrollment form. Space is limited and on a first come (paying) basis.

Fees – In 2018, the fee for this option was $530. This course is comparable to a 4 credit class. In comparison, tuition for a four-credit class is $1,932.

Updated Wednesday, July 11, 2018 by Mary Small