All too soon, it seems, the seasons pass by. While we are harvesting summer peaches, we need to start planning for the fall. Fortunately, Napa Valley's mild Mediterranean climate gives us some flexibility in planting dates. Nevertheless, planning now for cool-season crops will allow you to maximize limited space, invigorate your soil and try new vegetable varieties.
Whether you garden in a full backyard, a few raised beds or just some pots on the patio, you can still experiment with a variety of cool-season crops such as carrots, radishes, spinach, kohlrabi and cabbages.
Cool-season vegetables like broccoli and kale thrive when the average daytime temperature is 55°F to 75o F. Warm-season vegetables—think tomatoes, peppers and eggplants—prefer daytime temperatures from 65°F to 95oF. Pound for pound, we get more food from cool-season vegetables because we eat the vegetative part and not just the fruit. A cabbage, for example, is entirely edible, whereas we eat only the fruit of the pepper plant.
And like the gardener who enjoys the slower pace that cooler weather brings, many pests take a break as well. Some go dormant or simply reach the end of that season's generation. This slowdown can make it easier to garden without pesticides when the weather cools.
The workload may be less intense in fall and winter, but you can still be an active gardener. Growing legumes such as fava beans and peas will not only provide delicious fare for your table but also replenish your soil with precious nitrogen and other nutrients.
By keeping your beds planted, you provide habitat for beneficial insects, soil micro-organisms and earthworms. Any leftover plant material from summer, like tomato vines, can be composted and returned to the soil to nurture future crops.
When it comes to cool-season growing, the options are vast. Some fast-growing root vegetables, such as carrots and radishes, can be closely planted. In warm soil, they mature quickly so you can inter-plant with vegetables that grow above ground, such as lettuces, to maximize space. By picking only the outer leaves of lettuces rather than uprooting the entire plant, you can extend the harvest considerably. Peas are another great fall crop, and they can utilize vertical space—a boon for gardeners with limited square footage.
Seed companies such as Johnny's Selected Seeds, Territorial Seed Company and John Scheepers Kitchen Garden Seeds offer almost limitless choices for the fall and winter garden. In a couple of weeks, local nurseries will have good selections of vegetable seedlings for late-summer planting.
Remember, too, many cool-season vegetables are not only edible but stunningly beautiful. Kale, mustard and chard come in striking colors that can add eye appeal to a patio, walkway or planting bed.
Of course, even vegetables that thrive in cooler weather need sunlight, water, appropriate soil conditions and nutrients. You can prepare yourself for success at the upcoming Master Gardener workshop on cool-season vegetables (details follow) and plan now to ensure a healthy and abundant harvest this winter.
Workshop: The U. C. Master Gardeners of Napa County will host a workshop on “Growing Fall and Winter Vegetables” on Saturday, August 13, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Discover the joy of harvesting vegetables from your own garden in fall, winter and early spring. Topics will include timing, watering, fertilizing, managing pests and harvesting. On-line registration (credit card only). Mail-in/Walk-in registration (cash or check only).
Tree Walk: Join U. C. Master Gardeners of Napa County for a free guided tree walk through Fuller Park in Napa on Monday, August 8, from 10 a.m. to 11:30 a.m. Registration is recommended as space is limited. Meet at Fuller Park, corner of Jefferson and Oak Streets. Online registration or call 707-253-4221. Trees to Know in Napa Valley will be available for $15. Cash or check payable to UC Regents. Sorry, we are unable to process credit cards.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.