UCCE Master Gardeners of Riverside County

UCCE Master Gardeners of Riverside County We provide research based gardening information to Riverside County, Contact - http://ucanr.edu/sites/RiversideMG/advice/

To extend research-based knowledge and information on home horticulture, pest management, and sustainable landscape practices to the residents of California and be guided by our core values and
strategic initiatives." - UC Master Gardener Program Mission Statement

The UCCE Riverside County Master Gardeners are a group of volunteers who have completed a 10-month-long training program. They share

their knowledge through community service, educational outreach, propagation, lectures and demonstrations. The volunteers also answer questions from the public about home gardening via a telephone hotline and email. Call the Riverside Master Gardener Hotline: (951) 683-6491 ext. 231 Mon-Fri 9am - 12 noon Or leave a message and we'll call you back

Email your question to:
West Riverside County - [email protected]
East Riverside County - [email protected]

Include as much detail as possible and any photos that illustrate your problem/question.

🌿 Need Gardening Help? We’re Here for You! 🌿Spring is in full swing, and questions are popping up right along with your ...
08/30/2026

🌿 Need Gardening Help? We’re Here for You! 🌿

Spring is in full swing, and questions are popping up right along with your plants! The UC Master Gardeners of Riverside County Helpline is here to provide trusted, research-based answers to help your garden thrive. 🌱

🧑‍🌾 Whether you're in the Desert or West County, our trained volunteers can assist with questions like:

✅ What’s causing damage to your plants?
✅ How can you conserve water in your landscape?
✅ Why is your fruit tree struggling?
✅ How do you get started with composting?

💻 Best way to reach us: Email
📧 [email protected]

📧 [email protected]

📝 The more details you share, the better we can help—photos are always encouraged!

📞 Prefer to call? Leave us a voicemail:
(951) 955-2647

🔊 Please say—and repeat—your name and phone number clearly, and include a detailed description of your question.

🕰️ Our Helpline is staffed remotely by volunteers with limited weekly shifts, so we appreciate your patience—we’ll respond as soon as possible!

Learn more: ucanr.edu/sites/RiversideMG/advice

We’re here to help you grow with confidence this season! 🌼

🌱 Want to Become a UC Master Gardener? 🌱The UC Master Gardener Program of Riverside County is recruiting for its 2026–20...
08/29/2026

🌱 Want to Become a UC Master Gardener? 🌱

The UC Master Gardener Program of Riverside County is recruiting for its 2026–2027 Volunteer Training Classes!

Learn how you can turn your love of gardening into service to your community by attending an upcoming Information Session in Perris or Palm Desert. 🌿🍊

📅 Sessions begin September 9
📍 Riverside County residents only
📧 Questions? Contact Rosa Olaiz at [email protected]

For additional information, click here:

https://ucanr.edu/site/uc-master-gardener-program-riverside-county/become-master-gardener

See the flyer for dates, times, locations, and registration information. We’d love to welcome the next generation of UC Master Gardener volunteers! 💚

🌱 Ready to Grow Your Gardening Knowledge? 🌱 The UC Master Gardeners of Riverside County invite you to Home Gardening Bas...
08/29/2026

🌱 Ready to Grow Your Gardening Knowledge? 🌱

The UC Master Gardeners of Riverside County invite you to Home Gardening Basics 101, a three-session series designed for home gardeners of all experience levels!

🌿 Saturdays: September 26, October 3 & October 10, 2026

⏰ 9:00 AM–1:00 PM

📍 In person in Riverside

💲 $50 for all three sessions — materials included

Learn practical, research-based gardening techniques covering soils, mulch, compost, irrigation, landscape plants, kitchen gardens, wildfire resilience, landscape design, and gardening problem-solving.

🌻 Class size is limited to just 25 participants!
📅 Registration deadline: Thursday, September 10, 2026

📧 Registration is by email only. Contact Georgia Renne, Home Gardening Basics Coordinator, at [email protected] for information or registration.

Come Learn. Grow. Thrive. with the UC Master Gardeners! 🌱💚

🎨🌿 Explore the Art of Nature! 🌿🎨 Join this complimentary Nature with Watercolors Workshop on Saturday, August 29, at 10 ...
08/28/2026

🎨🌿 Explore the Art of Nature! 🌿🎨

Join this complimentary Nature with Watercolors Workshop on Saturday, August 29, at 10 a.m. at the Sycamore Creek Interpretive Center.

All necessary materials will be provided, and participants of all skill levels are welcome to attend. 🦋

Registration is limited, so please RSVP by August 27 to [email protected].

Address: 11875 Indian Truck Trail, Temescal Valley, CA 92883.

⚪ Clouds of Tiny White Insects? It Could Be Whiteflies!Whiteflies feed on plant sap and produce sticky honeydew that enc...
08/27/2026

⚪ Clouds of Tiny White Insects? It Could Be Whiteflies!

Whiteflies feed on plant sap and produce sticky honeydew that encourages sooty mold growth.

They are common on tomatoes, hibiscus, citrus, and many ornamental plants during warm weather.

Proper identification is the first step toward effective management.

Learn more from UC IPM:

https://ipm.ucanr.edu/home-and-landscape/whiteflies/ .tab=0



ucanr.edu/sites/RiversideMG

Photo credit: Jack Kelly Clark, UC IPM

Image: Sweetpotato whitefly adults and nymphs

🍊 Helping Preserve a Piece of Riverside County’s Citrus History 🌳On August 25, 2026, a select group of UC Master Gardene...
08/26/2026

🍊 Helping Preserve a Piece of Riverside County’s Citrus History 🌳

On August 25, 2026, a select group of UC Master Gardeners of Riverside County had the special opportunity to meet with citrus advisor Tom Spellman and Jacob Anderson, interpreter at Gilman Historic Ranch, for a walk-through of the ranch’s historic citrus grove in Banning.

The first step was to evaluate the grove’s current condition, identify immediate maintenance needs, and establish priorities for upcoming workdays. These efforts will help support the grove’s recovery and promote the long-term health of these treasured citrus trees.

🍊 Many of the trees are estimated to be 60 to 100 years old, making this much more than a gardening project—it is an opportunity to help preserve an important piece of our region’s agricultural history.

UC Master Gardeners are honored to have been given the privilege of helping revitalize this historic citrus grove and look forward to sharing its progress as the work continues. 🌿🍊

Contributions by: Thurman Howard
Photo credit: Thurman Howard

🌿 Community Opportunity: UC California Naturalist Certification Course 🦋We’re happy to help spread the word about this u...
08/26/2026

🌿 Community Opportunity: UC California Naturalist Certification Course 🦋

We’re happy to help spread the word about this upcoming UC California Naturalist Certification Course, offered through the Riverside-Corona Resource Conservation District.

📅 October 14 – December 16, 2026

📍 In-person in Riverside. 4500 Glenwood Dr., Riverside, CA 92506

🌱 Learn about Southern California’s natural environment through lectures, field trips, and hands-on, project-based learning.

Please see the flyer for registration details, course dates, cost, and contact information.

Registration deadline is September 30.



ucanr.edu/sites/RiversideMG

🌱 Reusing Potting Soil 🌱Have you considered reusing last year’s potting soil? What follows are suggestions as to how to ...
08/25/2026

🌱 Reusing Potting Soil 🌱

Have you considered reusing last year’s potting soil? What follows are suggestions as to how to make that happen.

First of all, if the plants occupying that potting soil were healthy and free of disease, you may reuse it safely. However, you will need to replenish the nutrients the previous plants and the watering depleted.

Replacing those spent nutrients can be done in several ways:

• Add new compost with a ratio of 1 to 3 (one part new to three parts old).
• Refresh the old potting soil by adding 20–30% new soil.
• Remove 6 inches of soil from the top and replace it with new soil.
• Add sphagnum moss, which contributes to aeration and has an excellent water-holding capacity.
• Add sand or perlite to improve drainage.
• Add vermiculite to help with water retention.
• To add nutrients, use worm castings, aged manure, compost, or mushroom compost.

If the potting soil hosted a diseased plant, that virus, fungus, or bacteria will remain in the soil for a long time. However, the soil can be reused by sterilizing it This can be done in several ways:

• Place 2 pounds of soil in the microwave at full power for 90 seconds.
• Place the soil on an oven-safe pan, cover with foil, and bake at 175–200 degrees for 30 minutes.
• Fill a black plastic contractor’s bag and leave it in the sun for 4–6 weeks. The solar heat will kill any pathogens.

Admittedly, at times the effort and time it takes to restore the previous soil simply isn’t worth it when purchasing a fresh bag of potting soil is so much simpler.

🌿 Happy gardening!

Article by Betty Guida, UC Master Gardener
Photo Credit: Unsplash

For additional information, Betty recommends these resources:

https://www.lsuagcenter.com/articles/page1671725785873

https://extension.okstate.edu/articles/2023/reusing_potting_soil

🌱 Ask a Master Gardener in Temecula! 🌱Have questions about your garden? Stop by the UC Master Gardeners of Riverside Cou...
08/24/2026

🌱 Ask a Master Gardener in Temecula! 🌱

Have questions about your garden?

Stop by the UC Master Gardeners of Riverside County “Ask the Master Gardener” Information Table at the Temecula Promenade Farmers Market!

📅 Wednesday, August 26, 2026
⏰ 9:00 a.m. – 1:00 p.m.
📍 Promenade Mall – Upper Parking Lot by Dick’s Sporting Goods
40460 Promenade Way, Temecula

Bring your questions about home gardening, landscaping, insects, irrigation, plant problems, and more! 🌻🐝🌿

Our Master Gardener volunteers will be happy to provide research-based gardening information and resources.

Enjoy the certified farmers market and stop by to say hello! 👋🌱

🌐 ucanr.edu/sites/RiversideMG

🌱 Grow Lab Propagation — Day Two! 🌱Another productive day at the UC Master Gardeners of Riverside County Grow Lab! Our v...
08/24/2026

🌱 Grow Lab Propagation — Day Two! 🌱

Another productive day at the UC Master Gardeners of Riverside County Grow Lab! Our volunteers continued propagation work while also tackling more of the ongoing Grow Lab renovations. 🪴🔨

Our Grow Lab is basically like running a small nursery—along with maintaining our demonstration gardens! During these triple-digit days, our seedlings and several other areas need watering twice a day to keep everything healthy and growing. 🥵💧🌱

It takes a lot of behind-the-scenes work, especially during the summer heat, and we appreciate our dedicated Master Gardener volunteers who keep it all going!

🌱Contributions by: Debbra Corbin Euston

📸 Photo Credit: Karla Kadow, Sheri Harris, and Debbra Corbin Euston

Address

2980 Washington Street
Riverside, CA
92504

Telephone

+19519550170

Website

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