Monthly tips are categorized by: To-Dos, What to Plant, or Pests and Diseases. Scroll through the list to see items in each category.
- Autumn Leaves - To Rake or Not to Rake
Fallen autumn leaves from healthy trees can provide valuable mulch, with the return of nutrients to the tree as the leaves slowly decompose. If you don’t like the look, you can add the leaves to the compost pile and later spread the compost under the tree. Diseased leaves should be put out with yard waste recycling to avoid spreading disease in your garden.- November
- Bone Meal for Bulbs?
Bone meal has traditionally been used as a phosphorus source for flower bulbs, but you may want to reconsider. If your soil is healthy, you may not need it and you may be better off with a balanced fertilizer designed for bulbs or even nothing at all. The nutrient content of commercial bone meal is lower than in the past due to the cleaning process, and the bone smell may attract raccoons or dogs to dig up the bulbs.- November
Composting is a good way to repurpose yard and kitchen waste, and it provides a free method to feed plants and improve soil structure. If you are unsure about how to begin composting, take a look at this simple how-to compost page. You can also go to the UCCE Composting Education Program website to learn more about free two-hour classes offered throughout the county.
As the weather warms up, compost piles dry out faster. Keep compost piles as damp as a wrung-out sponge to keep organisms alive and working on decomposing yard waste. Turning the pile to incorporate more oxygen also supports life in the compost pile.- January, February, March, April, May, June, July, August, September, October, November, December
- Frost Dates and Avoiding Frost Damage
The first and last frost dates for Santa Clara County are November 15 and March 15. First and last frost dates are important (but approximate) dates for gardeners to remember.
First frost date—this is the earliest date you should expect frost to occur. If you have plants that need to be brought in for the winter, or crops you need to pick before frost, this date will be important to you. Last frost date—after this date you wouldn't expect any more frosts. It's generally used as a milestone when planting outdoors, or pruning frost sensitive plants (such as citrus where you don't want to stimulate delicate new growth until danger of frost is past).
Note that microclimates in the county, and unusual weather conditions make these approximate dates.
When there's a threat of frost, make sure your frost-tender plants are well-watered. Soil that is damp can hold more heat than soil that is dry. According to the UC publication on the Principles of Frost Protection, ”when the soil is wet ... more heat is stored during daylight for release during the night.”
Frosts or a hard freeze can kill tender plants and can damage citrus, especially young plants so protection is a good idea on those cold, clear winter nights. Place stakes around tender plants and cover with clear plastic or fabric such as a sheet or old drapery. Don't let the material touch the foliage.
Wrap larger plants with strings of Christmas tree lights (incandescent bulbs not LED bulbs) or position a 100–150 watt spotlight in the center of the tree and cover the plant with a sheet. Turn the lights on at night.
If plants are potted, then move them to a sheltered area such as a porch, under the eaves on the south side of the house or even under a tree. Be sure to uncover them during the day. Moving them indoors to a cool room would be good if possible.
If you have plant damage from frost, wait until spring to prune. Early pruning can lead to further dieback along stems and branches because the dead material helps protect the plant from further damage.- January, February, March, November, December
- Garden Maintenance Items in the Fall
Remove or replace spent annuals. Trim woody or overgrown perennials. Trim diseased leaves from roses, camellias, rhododendrons, and azaleas. Discard in trash. Many insects and diseases over winter in plant debris so remove the yard waste from under plants. If you have oak trees, pines or junipers leave the fallen litter under these trees because it protects the roots.- October, November
- Growing Vegetables in Containers
Container grown vegetables can be decorative as well as good to eat. Almost any vegetable can be grown in a container if given the proper care. Eggplant, peppers, tomatoes, lettuce, onions, carrots, cucumbers and herbs do well. Use our Vegetable Planting Chart to decide when to plant.
One of the biggest problems is that containers dry out very fast and nutrients wash away. Both are solvable. Do not use clay pots, which dry out quickly. Plastic, composite or wooden half-barrels are good, but avoid dark colors that can absorb heat. Vegetables like a roomy container.
There must be drainage holes in the bottom but it is not recommended that you put pebbles or broken crockery in the bottom. Use a good commercial potting mix, not planter or planting mix. Group the containers together so they will shade one another.
The hot summer sun can heat the soil to unhealthy levels. Water whenever the soil is dry. You can test by digging your fingers into the dirt or using an inexpensive moisture meter. You may have to water more than once a day. A simple drip system is easy to install and will make your container garden almost foolproof. Fertilize every week with a water-soluble fertilizer.- February, March, April, October, November
- Harvest Kiwis
Pick kiwis in late fall while is still hard like an avocado, softening at room temperature. Watch the vine for signs of ripeness. A few fruit will turn soft or the skin color goes from greenish to full brown. Fruit can be left on the vine after leaves have fallen. You can store in the refrigerator for up to 4 months or at room temperature for about 2 weeks. More details about Kiwifruit Culture is provided by the California Rare Fruit Growers.- November
- Harvesting Sweet Potatoes
Hopefully the timing of your sweet potato harvest will work out for Thanksgiving dinner! They are usually ready 90-100 days after planting, when the end leaves start to yellow. You can dig down a little to see if the potatoes are large enough, but dig carefully or use your hands to avoid accidentally cutting the potatoes. If you plan to store them, cure them in a warm, humid environment for a couple weeks.- November
- Paint Trees to Prevent Sunburn
After deciduous trees have dropped their leaves, paint tree trunks with white latex paint diluted 1:1 with water to prevent sunburn. Preventing sunburn helps trees resist invaison by shot hole borers, which are tiny beetles that bore holes and lay eggs in the cambium layer of the tree. When the eggs hatch, young larvae feed and excavate tunnel galleries in the wood. For more information about identification and control see UC Pest Note on Shothole Borer.- November, December
- Persimmon Harvesting
Harvest persimmons. Fuyu persimmons are ready to harvest when they have their full orange color and are still slightly firm to the touch. Hachiya persimmons (with the pointy ends) must be soft and have translucent skin. If you eat an unripe Hachiya variety, you will gain a new understanding of the word “astringent”! Cut them off close to the fruit to avoid damage to the branch from yanking them off. The UC Master Gardeners of Solano County have a nice blog posting about Persimmons.- October, November
- Poison Oak
Poison oak is a California native plant that provides shelter and food for many native birds and other creatures. The downside is that at least 75% of us develop allergic contact dermatitis to the plant. Unwanted poison oak can be pulled or dug up by allergy-resistant friends, remove plants in early spring or late fall when the soil is moist and it is easier to dislodge rootstocks.
A complete list of management options, including herbicide control, is contained in the UC Pest Note on Poison Oak. Under no circumstances should poison oak be burned.- February, March, April, November
- Poisonous Plants List
As we approach the holidays, there are a lot of questions on poisonous plants. Fortunately, many of these plants have a very bitter taste that limits the amount of the plant eaten.
Poinsettia and mistletoe should be kept away from curious children, but the list includes other flowers and plants such as azaleas, calla lily, carnation, daffodil, foxglove, hydrangeas, iris, lantana, narcissus, poppy, sweet pea and tulips.
Different parts of the plant may be toxic. Consult the UC Poison Plant web page for detailed information.- November, December
2. What to plant
- California Poppies
The California poppy, seen on hillsides in late winter through early spring, can be grown in your own yard.
It can re-grow from a taproot or reseed itself rapidly throughout your garden and lawn, so consider whether this would be acceptable. If it is, seeds can be scattered now or with initial rains for vibrant color in a couple months.- November
- Flower Bulb Planting
Plant in rich, well draining soil. Soil that has grown annuals or vegetables should be good for bulbs.
Dig a hole three times as deep as the bulb's diameter. Mix a tablespoon of fertilizer high in phosphorus and potassium into the bottom of each hole, insert the bulb with the stem end on top and then cover with soil. Soak the area thoroughly.- November
- Garlic Planting
Plant individual cloves of garlic now and they will grow into full heads by next spring. Choose the largest cloves and leave the natural papery wrappers on them. Plant them in moist, well-drained soil in a sunny location with the pointy tips up, about one inch deep. Space cloves about four inches apart to leave room for large heads to develop.
The UCCE Master Gardeners of Napa County have more information about Growing Garlic.- November
- Going Native
Native shrubs, trees, and flowers are well-adapted to our climate and soil, and support native butterflies and bees and other wildlife. They are drought-tolerant once they are established, but need adequate water for the first year or two to establish a strong root system that will help nourish the plant for years to come. Planting them in the fall gives them time to settle in before being hit by the heat of the summer sun. Consult Water Wise Plants and the California Native Plant Society for more information.- October, November
- Plant Ornamental Flowers, Bushes and Trees
If you have purchased ornamental flowers, bushes, or trees and you haven’t gotten them into the ground yet, do it soon. The roots will have a much better chance of surviving and growing if the ground isn’t too cold. Developing a healthy root system early in the life of a plant is important for long-term success.- November
- Planting Onions
Growing your own onions can be rewarding. According to our Onion Cultivation Tips, plants started from seed in September should be ready to transplant in 50-60 days, so plan for November-December for planting at home.
The UC Davis Vegetable Research and Information Center also has information about Growing Onions.
The image shows a 3+ pound onion harvested in June 2016 at our Berger Edibles Garden.- November, December
- Vegetable Planting Chart
Wondering what vegetables can be planted now? To get the best success—whether planting from seed or transplants—refer to our Santa Clara County Vegetable Planting Chart. It's based on our own garden experiences.- February, March, May, June, July, August, November
3. Pests and Diseases
Examine your cabbage and broccoli plants for imported cabbageworms. Larvae are green and very hairy, with an almost velvet-like appearance. Handpick the worms. The adult cabbage butterfly is white with one to four black spots on the wings; they are often seen fluttering around the fields. Whitish, rocket-shaped eggs are laid singly on the undersides of leaves. The cabbageworm is active throughout the year in California. Use row covers or screening to keep the adults out of your vegetables. For more information see UC Pest Note on Imported Cabbageworm.- October, November, December
- Citrus Bud Mite - Leave It Alone
Have you ever seen weirdly shaped lemons or oranges that appear to have 'fingers'? This condition is caused by the Citrus Bud Mite.
It attacks newly forming flowers and fruits. The mite is only visible with a magnifying glass and has a elongated yellow body with four legs that appear to come out of its head. The mites feed inside the buds, killing them or causing a rosette-like growth of the subsequent foliage and distortion of flowers and fruit. The problem is usually limited to just a few fruit on the tree.
Previously recommended oil sprays have not been proved effective. This is one of those pests that is best left alone. The oddly-shaped fruit is edible.
For more information see UC Pest Note on Citrus Bud Mite.- November
- Codling Moth
"Worms" in your apples are actually the larval form of the codling moth. Codling moth larvae can cause a great deal of damage to apples, pears, plums and walnuts by penetrating the fruit and boring into the core.
Trees should be monitored every week for signs of infestation. Infested fruit should be removed and discarded, to break the coddling moth life cycle. Sanitation is an important non-chemical step in controlling this pest. Make sure to pick up fallen fruit promptly, and pick apples with holes that are still on the tree. This will keep future populations down.
Pheromone traps can be hung in isolated trees. But if you have just one apple tree don't bother. You will just attract codling moths to your tree.
Fruit can be bagged for protection, but this is a very labor intensive method. Heavy infestations may require the use of pesticides on the moths, before fruit is affected. For more information, refer to the UC Pest Note on Codling Moths.- March, April, May, June, August, September, October, November
- Limes with Stylar End Rot
Usually affects Persian and Bearss limes but can be on other limes and lemons. Depressed areas are firm or leathery and dry. It starts out looking like a water soaked, whitish-to-drab sunken patch at the base of the stylar tip (end) and can cover 1/4 to 1/2 of the fruit. Inside tissues at stylar end break down and become pinkish or brownish.
You can pick before mature to cut losses. Extremely high temperatures can bring it on.- November, December
- Peach Leaf Curl Preventive Care
If you had a serious problem this past year with peach leaf curl, where the leaves became red and distorted, spray the tree with a fungicide once all the leaves have fallen (late November, early December).
Generally a single early treatment when the tree is dormant is effective, although in areas of high rainfall or during a particularly wet winter, it might be advisable to apply a second spray late in the dormant season, preferably as flower buds begin to swell but before green leaf tips are first visible.
Use a fixed copper spray, as detailed in UC Pest Note on Peach Leaf Curl- November, December
- Sooty Mold
Aphids, scale, mealybug and whitefly all excrete sticky honeydew that is colonized by sooty mold fungi. By itself, the fungi cannot kill the plant but it can coat the leaves to the extent that sunlight is prevented from reaching the leaf surface. A strong stream of water will wash the mold off leaves. The mold can be washed off fruit with mild soap and water. See UC Pest Note on Sooty Mold for more information.
Ants protect the sucking insects from their predators in order to eat the honeydew. Keep ants out of trees and away from honeydew-producing insects by applying a sticky compound such as Tanglefoot on a tape wrapped around the trunk.
Trim tree limbs touching buildings, fences or other access points as well. Baits such as ant stakes placed under trees and shrubs may help reduce ant foraging in some cases.
For ant information, see the UC IPM Pest Note on Ants.- August, September, October, November
Termites are very common in Santa Clara Valley. The first sign of infestation may be the presence of winged forms or fecal pellets pushed out of the infested wood.
See the UC Pest Note on Termites to identify which type is present and the methods of control. Learn all you can before calling in the professionals.- April, November
- White Mold on Lettuce and Brussels Sprouts
White mold is a distinctive disease that most often affects stems and foliage at the base of cole crops* and lettuce plants. Affected tissue develops a soft, watery rot and white, cottony mycelium forms on the surface. Plants may wilt if stems are girdled by the decay. As affected tissue dries up, it turns yellow to white, and hard black sclerotia form on the surface or inside the dead stems. Get more information in the UC Pest Note on White Mold.
* Cole crops include broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, and kohlrabi- November, December