As most of our readers probably noticed, this summer in Contra Costa County was unusually cool. Some of you may have observed different behavior in your home gardens as a consequence, and might like to know how two of our Master Gardener demonstration gardens reacted to milder temperatures.
Very Distinct Gardens
Rivertown (East County)
Although the East County garden in Antioch, called ‘Rivertown’, is actually older than our Central garden ‘Our Garden’, in Walnut Creek, it was ‘inherited’ by Master Gardeners volunteers relatively recently. We didn’t have the luxury of developing it from scratch, and as a consequence, we also inherited the soil in the raised beds. As we’ve begun to steward this garden, we have encountered surprises that have thrown some curveballs that have presented challenges (or opportunities, if you will), including finding a weed barrier under the raised beds.
Given its history, Rivertown, led by Lisa Bramblet, continues to be a true experimental garden where Master Gardener volunteer learning goes hand in hand with our mission of education. We illustrate in real time, for instance, the proper way to improve the soil or to treat susceptible plants for disease and insects—including the three-striped potato beetle, a persistent pest on our tomatillos this summer! Additionally, Antioch is warmer in the summer than Walnut Creek, and that, too, presents a learning opportunity for our large and varied county.
Our Garden, Walnut Creek (Central County)
By contrast, we developed the 1-acre Walnut Creek garden ‘Our Garden’ literally from the ground up. We began with double digging to prepare the in-ground beds, and over the years, have had full control of the soil, which today is excellent. This is now both a teaching and a production garden from which we harvest produce to distribute to local charities, including Monument Crisis Center and White Pony Express.
Richmond Low Water Garden and Water Conservation Garden (West County)
You can read about the successes of the West County Water Conservation Garden and the Richmond Low Water Demo Garden in additional articles in this fall issue or by following the links.
2025 Seasonal Highlights
So what did the gardens experience during our unusual summer? Perhaps surprisingly, they were quite pleased with it! Here are some specifics.
Rivertown
After a scorching 2024, the cooler temperatures were a welcome relief, reducing the heat stress on the plants and contributing to higher output. The plants also appreciated the addition of new shade cloth. The tomatoes, in particular, did quite well under the shade cloth, and the eggplant and peppers were also pleased. Early on, the basil wasn’t happy about the heat, but it is currently thriving. Even a relatively cool summer in Antioch can be quite warm!
There is a small orchard in the garden with an Asian pear, pomegranate, orange, and fig tree, among other fruit, and it thrived this year. The little adolescent espaliered persimmon tree, in particular, is totally covered in persimmons! More fruit trees are planned for 2026.
Rivertown strives to demonstrate a variety of garden styles that might be of interest to the community. There is a thriving herb garden, a wheelchair-accessible trug planter, as well as a lovely vertical shade garden.
In accordance with our mission of learning and teaching, master gardener volunteers are conducting multiple ongoing experiments. The garden beds at Rivertown are accessed via crushed granite paths, and we are in the process of assessing whether the rocky material contributes to heat.We conduct regular soil tests in the quest to optimize the growing medium and are also studying the water, some of which is supplied by the city and some via a well.The quality of the water and the soil is foundational for garden success.
If you would like to learn more, you are invited to visit Rivertown at the Contra Costa County Fairgrounds (1201 W. 10th Street), which is open to the public every Tuesday from 10 a.m. until noon through October.
See this link for specific directions: About Rivertown Garden | UC Agriculture and Natural Resources.
Master gardeners volunteers are very fortunate to have this partnership with the city of Antioch and the state of California, and we look forward to expanding and strengthening that relationship in the future.
Our Garden in Walnut Creek
This demonstration garden is managed by Janet Miller, who told us that, although fruits and vegetables ripened a bit more slowly than in past years, the plants were extremely healthy and seemed relieved not to have to face another summer like last year! It was another blockbuster year for output success. Year to date, we have harvested over 12,000 pounds of produce, which has been given to charitable organizations in the community.
The overall success of the garden was helped by a major project earlier this year to ‘rat-proof’ the garden. Although the garden has been fenced with wire for some time, there has been a significant interest in our produce from rats who regularly helped themselves to bright red tomatoes and anything else they hankered for. To minimize sharing with these locals, our intrepid team, led by Steve Griffin, attached ¼” wire hardware cloth to the existing fencing around the entire perimeter of the garden and then added a 1-foot strip of metal flashing around the top. Although the rodents might climb up the hardware cloth, they aren’t able to navigate the slippery flashing to get over the fence, and our inventory shrinkage has been reduced to almost nothing.
The soil at Our Garden has been nourished over the years via organic amendments and best practices, such as no-till planting, composting in place, and cover crops. The key ingredient, however, is our homemade compost, continually in production via our dedicated composting team.As plants finish their growing season and are cut back, roots remain in the soil to feed it, while cut branches join the compost operation, now in full swing as summer winds down. This is the miracle ingredient in producing the garden’s bounty.
Some of the specific successes this year included the vineyard, which overachieved, providing over 600 pounds of grapes.
For the first time, the pole beans were grown on tall (6-7’) trellises, which they very much enjoyed, producing a bumper crop. The flowers were especially beautiful; zinnias and others luring pollinators to come and participate in the production process.
The cool weather also permitted leafy greens like lettuce, chard, and kale to continue to grow during the summer, rather than being relegated just to the cooler months.
As always, we try new varieties of vegetables, searching for those that will be most appealing to the public, who can acquire them for themselves during our plant sales. We enjoyed the apricot zebra tomato very much, as well as a healthy Korean avocado squash, Teot Bat Put.The small winter squash, Lodi, has been a new delight. Stay tuned for future updates on new and repeat varieties planned for 2026!
Were there any issues with unwanted insects or diseases? Very few. As ever, mosaic virus bothered yellow zucchini (you’re not alone if you have this challenge!). There have been some cabbage loopers (treated with Bacillus thuringiensis) on brassica shoots, which are now in the ground for the fall/winter. To deter ants and aphids that can introduce disease, we spread diatomaceous earth around the base of fruit trees in the orchard. But all in all, there were very few issues with flying and crawling pests this year!
Educational talks at ‘Our Garden’ in Walnut Creek continue on Wednesdays at 10 a.m. through October, so take advantage of these last opportunities of the season (see below.) The attendance, averaging over 50 people each week, continues to grow, and we are enthusiastic about and appreciative of our community’s commitment to ongoing education.
- October 01 - Growing Cherry Trees
- October 08 - Composting - 'Let me Count the Ways'
- October 15 - Tea from Your Garden
- October 22 - Planning a Rain Garden
- October 29 - Garden Hacks
Read: Seasonal Updates on the Richmond Low Water Demo Garden
Read: Successes of the Water Conservation Garden in El Cerrito