July Tips & Events for Santa Clara County

“Flowers and fruit are only the beginning. In the seed lies the life and the future.”

~ Marion Zimmer Bradley
 
Monthly Tips

Quiz: Debunking Pest Myths

Which of the following has scientific research debunked as ineffective in keeping rodents away from your edible garden harvests?


  • Ultrasonic repellers
  • Scented repellents (e.g., Irish Spring soap, dryer sheets, moth balls)
  • Wire crop cage with ¼-inch or smaller holes
  • Predator urine (e.g., coyote urine)
  • Trapping
Partially-eaten ripe tomato still hanging on a vine

Photo credit: Sarah Oh, Flikr
 
Orange California poppies surround a brown sign for the UCCE Master Gardeners of Santa Clara County
Come Visit!

Visit Our Demo Gardens

Here’s a fun idea for a summer outing—visit one of our Master Gardener demonstration gardens. Whether you stroll through the gardens, take a class, ask questions, or even garden with us, you’ll have an up-close and personal experience with plants that grow well in our area. Check out Martial Cottle Park, which showcases 50 tomato varieties, native plants, berries, experimental plots, an orchard, and more. Palo Alto features an edible garden and water-wise landscaping. Emma Prusch has an international rare fruit orchard, while McClellan Ranch offers visitors insights into growing Asian vegetables and herbs. Join us!
 
 

Wild World of Wasps

Not all wasps are pests—many are beneficial insects that help our gardens thrive. Mud daubers (Sceliphron caementarium) are an example: these black and yellow solitary wasps build intricate mud structures with 15–20 cells, provisioning each nursery with paralyzed spiders that they’ve captured. They’re excellent natural pest controllers and rarely sting humans, saving their venom for hunting. Beyond pest control, many wasp species also pollinate plants and prey on garden pests like caterpillars and aphids. Join the Wild World of Wasps webinar on July 17 to learn more!
Wild World of Wasps
 
Yellow and black mud dauber wasp showing curled antenna and a very thin waist connecting the thorax and abdomen

Photo credit: Kathy Keatley Garvey

 

Preventing BER
Tomatoes in different stages of ripeness with brownish grayish-black patches on bottoms

Blossom End Rot (BER) causes dark leathery patches on tomatoes. It happens when the plant doesn’t deliver enough calcium to the fruits, even if there is plenty of calcium in the soil. It’s most common on tomatoes that form when the plant is young, growing rapidly, and doesn’t yet have a large root system. What can you do? Keep the plants evenly watered because water is how they move minerals up from the soil. While adding eggshells to the planting hole isn’t exactly a garden myth, they take a very long time to decompose. Plus, in Santa Clara County, our soil generally has enough calcium already.



Photo credit: Canva
How to Water to Prevent BER
 

Bitter Squash Warning
Striped squash and yellow squash flower underneath the leaves of a squash plant.

Ever tasted bitter zucchini? Squash are part of the cucurbit family, and wild varieties produce the bitter-tasting chemical “cucurbitacin” to deter wildlife from eating them. Cultivated varieties have been bred for low levels of cucurbitacins, though mild bitterness can sometimes develop due to environmental factors like heat or stress. If you encounter a super bitter zucchini, don’t eat it, and pull out the plant. Extreme bitterness is likely due to seeds from an accidental cross with a wild cucurbit. Plants grown from those seeds may contain high levels of cucurbitacin, which can make people very sick.


Photo credit: Ying Chen
Bitterness Explained
 
Assortment of plants showing some of the wide variety of succulent plants

Photo: Clockwise from top-left, Sedum palmeri, Agave parryi ‘Confederate Rose,’ Echeveria, Agave ‘Kissho Kan,’ Allen Buchinski
 

Succulent Watering

Succulents store water in their leaves, stems, or roots, making them naturally drought tolerant. The key to healthy succulents? Avoid overwatering! While underwatered succulents can usually recover, overwatering often leads to fatal root rot. For success, plant in well-draining soil and let it mostly dry out between waterings. Water more frequently during active growing seasons and reduce watering during dormancy. Remember: it’s better to err on the dry side. Learn more about succulent care on our website and join us for our July 12 library talk on these fascinating, water-wise plants!
 
July 12 Succulent Talk
 

Quiz Answer

Scented, predator, and ultrasonic repellents have been debunked by science.

  • Rodents may initially dislike the scent of repellents or urine, but they will get used to it.
  • There is little evidence that sound, magnetic, or vibration devices provide adequate control of mice or rats. Gophers are not easily frightened by these devices.


To learn more about common pest myths (and facts), check out this article or watch this video from UC Urban IPM educator Lauren Fordyce.



For management tips specific to various vertebrate pests, visit the UC IPM website on Vertebrate Pests in Gardens.
Debunking Pest Myths
 
Wire cage keeps animals from a young fruit tree at the Guadalupe Historic Orchard

Photo: Cage keeps animals from a young fruit tree at the Guadalupe Historic Orchard, Ying Chen
 

More July Tips and To-Dos

For more gardening tips and to-dos, visit the monthly tips archive on our website. It is perfect for browsing, and while you may recognize some of the content, you’re sure to find something new. It starts with to-dos for the month, just the thing to review before heading out to your garden.
More Tips and To-Dos
 
 
 

Upcoming Events

Our monthly Plant Clinic Online is an opportunity to chat with a Master Gardener via Zoom to diagnose a plant problem. You can also listen and learn while other people ask questions. It takes place on the second Tuesday of the month (July 8) from 7 to 8:30 pm. Priority will be given to questions that are emailed in advance; instructions are in the Zoom registration confirmation. Registration required.


PADG Bugs, Beaks & Bounty in Your Veggie Garden: Creating a Healthy Habitat, Saturday, July 5, 10:00 am–11:15 am, Palo Alto Demonstration Garden at Eleanor Pardee Park, 851 Center Drive, Palo Alto


PADG Open Garden Saturdays, July 5, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


Plant Clinic Online, Tuesday, July 8, 7:00–8:30 pm, Online


PADG Open Garden Saturdays, July 12, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


Success with Succulents, Saturday, July 12, 10:30 am–11:45 am, Willow Glen Public Library, 1157 Minnesota Avenue, San Jose


Growing Your Own Cut Flower Garden, Saturday, July 12, 11:00 am–noon, Mountain View Public Library, 585 Franklin Street, Mountain View


Healthy Bees, Healthy Gardens, Saturday, July 12, 11:00 am–noon, Central Park Library, 2635 Homestead Road, Santa Clara


Wild World of Wasps!, Thursday, July 17, noon–1:00 pm, Online


MCP California Native Plant Sale, Saturday, July 19, 9:00 am–noon, Martial Cottle Park, 5283 Snell Avenue, San Jose


MCP Succulent Open House & Sale, Saturday, July 19, 9:00 am–noon, Martial Cottle Park, 5283 Snell Avenue, San Jose

 

PADG Open Garden Saturdays, July 19, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


STDG Preventing Vertebrate Pests from Eating Your Garden, Saturday, July 19, 1:00–3:00 pm, Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles Street, Sunnyvale

 

PADG Open Garden Saturdays, July 26, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


Growing Your Own Cut Flower Garden, Saturday, July 26, 11:00 am–12:30 pm, Berryessa Branch Library, 3355 Noble Avenue, United States

 

PADG Open Garden Saturdays, August 2, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


MRDG Starting Your Cool Season Garden, Saturday, August 9, 10:00 am–noon, McClellan Ranch Preserve, Community Garden Area, 22221 McClellan Road, Cupertino
Check our calendar for the latest schedule of events. Videos of many past presentations are also available.
 

About Us

University of California Master Gardener volunteers promote sustainable gardening practices and provide research-based horticultural information to home gardeners. Visit our website for more information including:


Have a gardening question? Ask us. We’re here to help!
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