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Fall and Winter California Gardening Part 2: Benefits and Challenges
Fall and winter are the ideal seasons for gardening in mild-winter and hot-summer California areas, with unique seasonal benefits but also many challenges.
This is the 2nd in a series of articles with information and tips for California gardening from late summer or fall through spring.
Home gardening is one of the safest and most-rewarding activities during the COVID-19 pandemic. For other helpful articles, see the GardenZeus blog page Dig In.
Sunlight is Seasonal
Is there a catch to gardening from fall through spring? Depending on your local climate, environment, and garden, there might be a few. But the main one is sunlight.
Because of seasonal changes in the tilt of the Earth, days grow shorter after the summer solstice and longer again after the winter solstice. The sun appears progressively lower in the sky from early summer to midwinter. Garden areas that receive full sun during summer may become partly or entirely shaded during fall and winter.
Obstructions that don’t block sunlight during summer may be problematic and cause seasonal shading during fall and winter, including fences, trees, and nearby buildings.
Better plant growth and harvests. Most plants and trees grow best at cool-to-warm temperatures, and most annual vegetables, including many warm-season vegetables, produce better yields during cool weather.
Reduced plant stress. Heatwaves are stressful to most plants and trees, and prolonged hot weather during summers in many California areas can cause a range of problems for plants. Annual vegetables tend to go to seed quickly, have reduced harvests, and expire early in response to hot weather. One heatwave lasting a week or two can functionally end the veggie-gardening season for summer, even in coastal areas.
Unique growing options: Certain veggies can only be grown successfully in some California climate areas from fall through spring. In hot-summer areas, this includes most cool-season veggies. Garlic grows best in most of California from fall or early fall through spring or early summer.
Rainfall. The natural rainfall cycle from fall through spring in California provides water that’s usually better for plants and gardens than municipal water. Rainy periods help to reduce the need for irrigation.
Plant Establishment. Perennials and trees planted from fall through late winter have more time to overcome transplant shock, grow deeper root systems, and establish symbiotic relationships with soil microbes and living systems, all of which help them to thrive, produce good yields or blooms, and stay healthy during hot weather. When planted in the fall or spring, many California native plants establish best with the natural rainfall that occurs over late fall and winter.
Comfortable Working Temperatures. Daytime temperatures in much of California from fall through spring are often in the range of 50 to 85ºF. Not only are these temperatures easier for most plants, they’re more comfortable for gardeners.
Reduced Pests and Diseases. Cool weather slows insect reproduction, and occasional winter frosts reduce populations of pest insects. When plants are less stressed by weather and environment, they naturally discourage or fight off pests and diseases more effectively. Many California areas have reduced problems with pests and diseases from fall through spring.
Soil Fertility and Living Soil Systems. Mediterranean-climate soils need organic matter year-round to support soil ecosystems and microbe populations. When organic matter in soil is depleted, plant-sustaining microbes become stressed, have less to eat, and may die. Living plant roots are one of the primary sources of organic matter for soil. Planting year-round in California helps to maintain soil life and fertility.
Year-Round Produce, Exercise, Enjoyment, Relaxation, and Learning. We have the opportunity in much of California to enjoy home-grown ornamentals, veggies, and fruits year-round, which brings with it all of the many benefits of active gardening.
Challenges with Gardening from Fall through Spring
Sunlight is seasonal. See above. If you can overcome this issue, almost everything else is manageable.
Plant and seed availability. Most national seed retailers and even local California nurseries are on the same retail cycle as the rest of the country, with the majority of seeds, starts, and plants arriving for sale by late winter or early spring. Pickings are often comparatively slim both by mail order and at local stores from late summer through winter. While some plants and starts, such as garlic and narcissus, are available locally in late summer or fall, it may be difficult to locate many of the basic seeds or plants you might want. Some nurseries and big-box stores carry seeds and supplies for vegetable gardening year-round where local conditions are good for fall/winter planting. Most supply problems can be overcome by ordering seeds for fall planting during spring, or by putting in extra time and effort to find sources. To save you time, we include in our plant information sources for seeds, plants and supplies.
Seed Germination. Outdoor seed germination may be slow and seeds may tend to rot before germinating during cold, wet weather. Start seeds early in fall during warmer weather, shift to starting seeds indoors during cool weather, or wait for periods of warmer weather to start seeds during fall and winter.
Cold weather and frosts. Many California areas with mild winters still have occasional frosts, and some areas have hard frosts that might last a day or longer. In areas with mild and occasional frosts, it’s usually sufficient to monitor weather and provide temporary protection for frost-sensitive plants, such as by covering them overnight with cloth sheets or tarps. Cold frames are often sufficient for gardening over winter in areas that receive short hard frosts lasting less than a day. Future articles in this series will provide guidance and tips by California Climate Zone.
Leaf mildews and other fungi. Rainfall and high humidity encourage leaf mildews and other fungi. These are especially problematic in coastal areas. In some coastal areas it can be difficult to succeed with vegetables that are susceptible to mildews from fall through spring, such as zucchini, squash, cucumbers, chard, peas, and others. For small gardens, alkaline foliar sprays such as milk with 1 teaspoon baking soda per cup, or water with 1 tablespoon of baking soda and 1 tablespoon of tea-tree oil per quart, will discourage most leaf mildews.
How Do I Start with a Fall/Winter Garden?
Once you’ve made the perspective shift to recognize that fall/winter gardening is not only possible but ideal in many California areas, how do you get started? We will explore this topic in the next article in this series, “Fall and Winter California Gardening Part 3: Getting Started.”