Chilly nights challenge our citrus trees, succulents and other frost-tenderlandscape plants. On top of the seissues, holiday commitments take up a lot of the time that one might otherwise spend in the garden.
So what should a gardener be doing this month?Some tasks are priorities, so let's tackle those first. If you have citrus trees or other tender plants, you must mitigate their exposure to frost or they will suffer. Already I have recorded night-time temperatures below 30°F at my home.
I have five citrus trees in four locations, so I use a combination of strategies. For the two trees close enough to the house to reach with an outdoor extension cord, I have strung Christmas lights (not LED type) in the branches. I plug in the lights on cold nights. Another tree, a dwarf citrus, is short enough that an old patio umbrella clears its branches. I toss an old comforter over the umbrella ribs when frost threatens. For the other two citrus, I set up ladders to support tarps and old blankets. Once the temperature begins to rise in the morning, I remove all the coverings and unplug the lights. Unless we get an arctic blast, all of these trees should survive the winter.
Water is also a priority. Until rains thoroughly wet the soil, I pay attention to my rain gauge. If we have less than an inch of rain in a two-week period, I figure that any actively growing plants will need irrigation. In my garden, that's mostly vegetables. My fall-planted greens are producing lots of leaves for stir-fry and salad, and November garlic is beginning to emerge.
Citrus trees will also need some water, especially if the weather is cold. During the summer I used gray water from my laundry to water my roses; now that those plants are going dormant, I'm using the gray water for citrus trees. I have switched to a plant-friendly laundry detergent and have not noticed any negative effect on the plants irrigated with gray water. But note that I only use gray water on trees and shrubs; the vegetables get potable water.
Already we have had enough rain in Napa Valley to start greening our hillsides. But the same rains have prompted weeds to emerge in my garden beds. While these weeds are small, they are easy to pull or hoe. Weeds take just as much water as edibles, so removing them now will conserve water for the plants I want.
As you weed, note areas of bare soil. If possible, cover bare spots with mulch or compost, or plant a cover crop if you can keep it moist. Winter is hard on soil. Rain compacts it; wind and sun dry it out. Soil is the foundation for all of your plants so protect it. Earthworms, fungi and other soil microorganisms will reward you with healthier soil next spring when it's time to plant.
Last but not least, finish your fall cleanup. Remove spent vegetable plants. Put diseased plant material in your yard-waste bin rather than in your compost pile. Most backyard compost piles do not get hot enough to destroy pathogens. In contrast, the waste-management companies compost at high temperatures that do control bacterial and fungal diseases. Rake up leaves and other litter to eliminate hiding places for snails, slugs and harmful insects.
In next week's column, we'll look at December gardening activities that are less like maintenance and more like fun. Although I have to admit, on sunny winter days I am perfectly happy to be outside even if all I do is pull weeds. It makes a nice break from working on the computer or in the house.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Pruning and Maintenance” on Saturday, January 9, from 10 a.m. to noon, at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. This workshop will feature demonstrations of proper pruning techniques. Master Gardeners will discuss types of roses, common rose diseases and routine maintenance. On-line registration (credit card only);Mail-in registration (check only).
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.org/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.