September Tips & Events for Santa Clara County

“Give me juicy autumnal fruit, ripe and red from the orchard.” ~Walt Whitman

Fall Garden Fair is October 3

Fall is a wonderful time to garden in Santa Clara County. Cool-season vegetables rival summer’s bounty, with crisp greens, broccoli, peas, and more thriving in cooler weather. Fall is also the ideal time to plant California natives, allowing them to take advantage of warm soil and autumn rains to set roots before next summer’s heat. You can shop for natives, cool-season vegetables, garlic/shallots, and ornamentals at our Fall Garden Fair on October 3. Enjoy educational talks, demonstrations, information booths, and kids’ activities. Come learn, choose plants, and get inspired for fall gardening!

Photo credit: Mary Werthman

Grow Your Own Lettuce

Lettuce is an excellent cool-season crop for container gardening. Its shallow roots and wide variety of colors, sizes, and leaf shapes make it suitable for many types of containers. You can easily start your crop from transplants or you can direct seed — but keep the soil between 60°F and 75°F to allow for germination. Plant seeds close together, then gradually harvest by picking the outer leaves or thinning the plants as they mature. Use a high-quality potting mix and maintain consistent watering. Best of all, this fast-growing green can yield your very first fresh salad in as few as 45 days.

Photo credit: Renee’s Garden

Growing Garlic and Shallots

In our county, garlic is best planted in mid-October through November, while shallots can be planted from fall into spring. So, September is the perfect month to learn how to prepare for growing these culinary delights! Come to the Sept. 12 talk at the Willow Glen Library or the Sept. 19 talk at our Martial Cottle Park Demo Garden to learn more. Seed garlic and shallot bulbs are often sold out before they are shipped in the fall. Master Gardener-grown garlic and shallots will be available at the Sept. 19 plant sale too!

Photo credit: Kathy Kaplan

Giant Whiteflies

Spirals of wax on the underside of a leaf are a tell-tale sign of a giant whitefly infestation. Both nymphs and adults feed on the sap of many host plants. Unmanaged giant whiteflies and their waxy deposits eventually cover upper and lower leaf surfaces while their honeydew secretion encourages the growth of black sooty mold. The waxy and sooty buildup hinders the plant’s photosynthesis. Washing affected leaves with a strong stream of water performs as well or better than chemical treatments. Insecticide is not recommended as it kills both the giant whiteflies and their natural enemies.

Photo credit: Mary Werthman

Winter Cover Crops

As you clear out your summer garden, consider planting cover crops in September or October to enrich your soil. Cover crops protect and improve garden soil during the off-season by adding organic matter, fixing nitrogen, loosening clay soil, and preventing erosion. They grow through winter, are cut down as they begin to flower, then chopped and returned to the soil to decompose. Fava beans are especially popular in our area. Try growing some as a cover crop while letting others mature into beans for a delicious treat. But buy seeds early—they can become scarce as fall approaches.

Photo credit: Otaliruna, iStock

Interested in Composting?

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:

• More Monthly Tips
• A complete list of Upcoming Events and Classes
• Extensive Garden Help
• Videos of garden tips and past online presentations

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