September Tips & Events for Santa Clara County
“If you’ve never experienced the joy of accomplishing more than you can imagine, plant a garden.”
~Robert Brault
Monthly Tips
Quiz: What Do These Plants Have in Common?
Perhaps you’ve seen these plants in a garden, by a highway, or maybe even in a nursery? What do all these plants have in common?
Photo: (clockwise from top left) Tree-of-heaven, English ivy, Spanish broom and highway iceplant, Ying Chen
Fall festival
Image credit: Martial Cottle Park
Coming October 5: Fall Garden Fair
Mark Saturday, October 5 on your calendar so you won’t miss our Fall Garden Fair at Martial Cottle Park’s Fall Festival. You’ll find loads of talks and information booths for inspiration and education about fall gardening. In addition to children’s activities, we’re holding our first-ever seed swap, so bring seeds to share with your neighbors. Kickstart your winter garden at our plant sale, offering cool-season vegetable, ornamental, and native plant seedlings plus succulents and garlic & shallot bulbs—all selected to thrive in Santa Clara County’s specific growing conditions. See you there!

Date: Saturday, October 5, 9 am–2 pm
Where: Martial Cottle Park, 5283 Snell Ave San Jose at the Master Gardeners Demonstration Garden
Cost: Free admission, $6 parking at Martial Cottle Park
Master Gardeners Fall Garden Fair
Enrich Your Soil with Cover Crops    
As your summer vegetable garden wanes, consider planting cover crops to protect and nourish your soil through the winter. Cover crops aren’t meant to be harvested—their purpose is to add nitrogen and other nutrients to your soil, suppress weeds, and improve soil composition. Try legumes such as fava beans, peas, common vetch, and bell beans for a good dose of nitrogen, or try cereals such as oats and barley to help build organic matter. Once spring arrivesbut before they set seedchop up the cover crop and turn it into the soil. After a few weeks of decomposition, your soil will be ready for spring planting.
Close up of a white lava bean flower in front of green foliage

Photo: Cover crops can improve soil quality, © 2014 by Mihai Costea, phytoimages.siu.edu

Cover Cropping in Home Vegetable Gardens
Letting bitter melon fruit mature for seed collection

Seed Saving
Are you looking to save seeds from a vegetable or a flower you like? Here are a few things to consider when you are saving seeds. Start by determining which plant you want to collect from. If you have a hybrid variety, be aware that the seeds may not produce a plant that is the same as the parent plant. Find a healthy plant or fruit with the characteristics you like and let the seeds mature before collecting. Use either the dry or wet method to separate and clean your seeds. Once they are completely dried, label with the variety and the date. Store them in a cool, dry place until they are ready to be planted.

Photo: Letting bitter melon fruit mature for seed collection, Ying Chen
Seed Saving Basics
When to Plant Vegetables?
Planting symbols for the vegetable planting chart
Our vegetable planting chart has become an indispensable tool for local gardeners. This popular resource helps you determine the optimal times to plant various vegetables in Santa Clara County, for both direct seeding and transplanting seedlings.

Recently updated with more content and improved readability, it’s now even more user friendly. As you plan your winter vegetable garden, this chart serves as an excellent guide for selecting the right crops. Visit our website to access this valuable resource and set yourself up for gardening success.
Vegetable Planting Chart
Check Vegetable Roots & Stems
Verticillium wilt in Tomato stem
As our summer growing season comes to an end and you start pulling out spent or unproductive plants, take a moment to examine their roots and stems. Do the roots show signs of root knot nematodes? Do the stems show signs of Verticillium or Fusarium discoloration? If your plants suffered from any soilborne pathogens this year, consider strategies for managing it next summer. If you have the space, you could plant in a different spot next year. If you can’t rotate locations, try choosing varieties that are marked as being resistant. You could even grow in containers for a season.

Photo: Tomato stem on left shows discolored vascular tissue caused by Verticillium wilt, Jack Kelly Clark, UC ANR
Soilborne Pathogens
Periwinkle - Vinca major - is an invasive plant in California

Photo credit: Periwinkle (Vinca major) is an invasive plant in California, Cynthia Zimmerman

Quiz Answer

All of these plants are non-native and considered invasive by the California Invasive Plant Council (Cal-IPC). Many are aesthetically pleasing and low-maintenance, making them attractive landscaping plants. But, due to their rapid growth habits and lack of predators, they outcompete the native plant population. In addition, they spread easily without human assistance, and often escape into naturalized, wild areas, impacting existing ecosystems.


Before purchasing, planting, or sharing a plant, please check the Cal-IPC site, or PlantRight to see if it is invasive, and if it is, find alternatives to the plant.

Don't Plant a Pest

More September Tips and To-Dos

For more gardening tips and to-dos, visit the monthly tips archive on our website. Perfect for browsing, you may recognize some of the content, but 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 & 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 (September 10), from 7–8:30 pm. Priority will be given to questions that are emailed in advance; instructions are in the Zoom registration confirmation. Registration required.

Summer Fruit Tree Pruning, Saturday, September 7, 9:30–11:30 am, Guadalupe River Park Historic Orchard, 494 Seymour Street, San Jose

Planning for the Cool Season, Saturday, September 7, 10–11 am, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

PADG Open Garden Saturdays, Saturday, September 7, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Growing Vegetables in Fall and Winter, Saturday, September 7, 10:30–11:30 am, Gilroy Public Library, 350 W 6th Street, Gilroy

Replace your Lawn with Low Water/Low Care Plants, Saturday, September 7, 1–3 pm, Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles Street, Sunnyvale

MCP Open Garden Sundays, Sunday, September 8, 1–3 pm, Martial Cottle Park, 5283 Snell Avenue, San Jose

Growing Culinary Herbs in Santa Clara County, Tuesday, September 10, 6:30–7:30 pm, First Floor, Mountain View Public Library, 585 Franklin Street, Mountain View

Plant Clinic Online, Tuesday, September 10, 7–8:30 pm, Online

PADG Open Garden Saturdays, Saturday, September 14, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

STDG Ask a Master Gardener, Saturday, September 14, 10 am–noon, Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles Street, Sunnyvale

Growing Cool Season Vegetables, Saturday, September 14, 10 am–noon, McClellan Ranch Preserve, Community Garden, 22221 McClellan Road, Cupertino

You Can Grow Cool Season Vegetables!, Saturday, September 14, 11 am–1 pm, Tully Library, 880 Tully Road, San Jose

Winter's Bounty: Six Steps to a Successful Cool Season Garden, Sunday, September 15, 1:30–2:30 pm, Rinconada Library, 1213 Newell Road, Palo Alto

Growing Vegetables in Fall and Winter, Tuesday, September 17, 6:30–7:30 pm, Morgan Hill Public Library, 660 W. Main Avenue, Morgan Hill

Drink What You Grow, Wednesday, September 18, 7–8:30 pm, Los Altos Library, 13 S. San Antonio Road, Los Altos

Improving Professional Ant Control Services, Thursday, September 19, noon–1 pm, Online

PADG Open Garden Saturdays, Saturday, September 21, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Growing Blueberries in Santa Clara County, Saturday, September 21, 10:30–11:45 am, Willow Glen Public Library, 1157 Minnesota Avenue, San Jose

Parks for Pollinators BioBlitz 2024, Saturday, September 28, 9:30 am–noon, Everett N. Eddie Souza Park & Community Garden, 2380 Monroe Street, Santa Clara

PADG Open Garden Saturdays, Saturday, September 28, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto
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:


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