September Tips & Events for Santa Clara County
September is dressing herself in showy dahlias and splendid marigolds and starry zinnias. ~Oliver Wendell Holmes
Monthly Tips
Quiz: What Caused This?
Have you ever pulled up a plant and seen roots like these? Are those lumps and bumps normal or is there something wrong? Hint: These are roots of a tomato plant, but many other plants, even trees and weeds, can be affected. Scroll to the end to learn the answer.
Photo: Jack Kelly Clark, UC ANR
Lumps and bumps on a plant roots - by Jack Kelly Clark - UC ANR
Drought irrigation
Photo: Canva stock image
Time to Reduce Watering

With its shorter days, the changing season means your plants will need less water. If your landscape watering is set up with a timer, adjust the timer settings to reduce the time each station runs. Keep in mind that it’s not just the length of time that matters, it’s the amount of water being applied. So it can be useful to check the soil where you’re irrigating and adjust accordingly. “Moist but not soggy” is the general goal, but with the current drought, dialing back the water and watching how the plants deal with it is a good strategy.
Success with Houseplants 
Houseplants - by Allen Buchinski
If you enjoy houseplants, Ernesto Sandoval, the Director of the UC Davis Botanical Conservatory can help. He has advice about selecting plants that tolerate the light and humidity levels of your home as well as tips about how to care for them. For instance: Overwatering is the number one killer of houseplants. Allow succulents to dry completely between watering. Water leafy plants that recover easily from wilting when they start to droop. For more information, including many useful tips, watch his video presentation.

Photo: Allen Buchinski
Is It Really a Pest?
IPM Staff uses hand lens to examine aphid eggs on dormant buds-by Jack Kelly Clark - UC IPM
You see insects in your garden and your first reaction may be to reach for neem oil or other insecticides to kill off the little invaders. But wait! Chemical intervention may not work, might not be necessary, and may even kill off beneficial creatures that your garden needs. Instead, determine first whether the pest really is a pest. This UC plant diagnostic tool can help figure that out and provide mitigation options. Identification is a key element of Integrated Pest Management (or IPM), a process Master Gardeners suggest you use to solve pest problems while minimizing risk to people and the environment.

Photo: IPM staff uses hand lens to examine aphid eggs on dormant buds, by Jack Kelly Clark, UC IPM Program
Transitioning to Winter Vegetables
It’s time to plant winter vegetables while the soil is warm enough to help them get established. But what if your garden is still full of summer crops? Look critically at your plants. Is that tomato sickly? Does it only have a couple of green fruits left on it? Does that squash have powdery mildew? Are the beans dropping their leaves? Make room by pulling out weak or less productive plants. Snip the flowers on summer plants to prevent new fruits from forming that won’t have time to ripen. Tuck seedlings between mature plants, taking advantage of the shade. See our videos on cool season vegetables, including a 3-session course for more inspiration.
Lettuce grows well in our cool season - by Gary Bachman - Mississippi State University Extension
Photo: Lettuce grows well in our cool season, Gary Bachman, Mississippi State University Extension
Label and store seeds in airtight containers in a cool - dark place -UC Marin Master Gardeners
Photo: Label and store seeds in airtight containers in a cool, dark place, UC Marin Master Gardeners
Time for Seed Saving

As we reach the end of the summer garden season, were there some vegetables you particularly loved this year? If yes, consider saving their seeds for next year’s garden. The easiest seeds to save are from self-pollinating plants like beans, peppers, lettuce, and tomatoes. Be aware that seeds from hybrid varieties may not breed true. Dry fruit plants like beans and peas can just be separated from their pods, dried, and stored. But tomatoes require a “wet” method where seeds are scooped into a container, fermented, washed, dried, and stored. Come to our Seedy Saturday Seed Exchange on 9/24 to learn more.
Martial Cottle Park Fall Festival
The Martial Cottle Park Fall Festival celebrates the agricultural heritage of the Santa Clara Valley. This all-ages- and dog-friendly event will feature live music, food trucks, vendor booths, and more. The Master Garden Demonstration Garden will be open for visitors with free classes and tours. Stop by to see what’s growing and ask your own gardening questions.
  • When: Saturday, October 1, 9 am–2 pm
  • Where: Martial Cottle Park, 5283 Snell Avenue, San Jose
  • Cost: Free admission, $6 parking on-site (space limited)
Martial Cottle Park Fall Festival
Healthy celery roots compared to nematode  infested roots - Michigan State University
Photo: Healthy celery roots compared to nematode infested roots, Michigan State University
Quiz Answer: Root Knot Nematodes

The swellings on the roots in the quiz picture above are caused by microscopic creatures called root knot nematodes. They can infest a wide variety of plants and easily spread via soil left on tools or shoes. Infested plants may not die but may be sickly or less productive. When you pull out your annual plants, inspect the roots, especially if they didn’t do well. Avoid spreading root knot nematodes by cleaning tools thoroughly. Consider letting an infested bed lie fallow for a season, or plant a cover crop next summer of French marigolds, which help suppress some nematodes.
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 Saturday of the month (September 10), from 10–noon. Priority will be given to questions that are emailed in advance; instructions are in the Zoom registration confirmation. Registration required.

Creating a Native Plant Rain Garden, Saturday, September 3, 10–11 am, Palo Alto Demonstration Garden, 851 Center Dr, Palo Alto
 
Open Garden Palo Alto Demonstration Garden, Saturday, September 3, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Dr, Palo Alto
 
Open Garden Palo Alto Demonstration Garden, Saturday, September 10, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Dr, Palo Alto

Cool Season Vegetables to Grow in Fall and WinterSaturday, September 10, 10:30–11:30 am, Gilroy Public Library, 350 W 6th St., Gilroy
 
Waterwise Landscaping, Tuesday, September 13, 6:30–8:30 pm, Fremont Unified High School District Adult Education, 589 W Fremont Avenue, Sunnyvale

Cool Season Vegetables to Grow in Fall and WinterWednesday, September 14, 7–8 pm, Morgan Hill Library, 660 West Main Avenue, Morgan Hill
 
Arachnophobia, Thursday, September 15, noon–1 pm, Online

How to Grow Wildflowers From Seed and Seed Exchange, Saturday, September 17, 10–11:30 am, Martial Cottle Park, 5283 Snell Avenue, San Jose
 
Open Garden Palo Alto Demonstration Garden, Saturday, September 17, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Dr, Palo Alto
 
Open Garden Palo Alto Demonstration Garden, Saturday, September 24, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Dr, Palo Alto
 
Seedy Saturday Seed Exchange, Saturday, September 24, 10–11:30 am, Martial Cottle Park, 5283 Snell Ave, San Jose

Martial Cottle Park Fall FestivalSaturday, October 1, 9 am–2 pm, Martial Cottle Park, 5285 Snell Avenue, San Jose
Check our calendar for the latest schedule of events. Videos of many past presentations are also available.
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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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