In our climate, fruit trees do need to be watered periodically to stay healthy. A fruit tree's water needs depend on its size, day length and the weather (air temperature, humidity and wind). Under-watering will reduce fruit size and tree growth. With extreme water stress, fruit can sunburn and may shrivel and drop, and the tree may lose its leaves.
Can your fruit trees survive with less water? Yes, they can. In a year with normal rainfall, the soil at the beginning of May is holding as much water as it can. Ideally, you would observe the surrounding hills and start watering when the grass turns brown—a sign that the top six inches or so of soil have dried out. At that point, young trees need to be watered every 10 days to 2 weeks. Established trees only need water every three to four weeks from June through August. This infrequent watering encourages deeper roots, which makes more water available to the tree.
Trees that are one to two years old need just one to two gallons of water per day (applied 15 to 30 gallons at a time). A mature tree can use 50 gallons on a hot summer day. It might need 1,000 gallons every four weeks to replenish the water it takes out of the soil.
Make sure you water slowly enough so that all of the water is absorbed. Younger trees are more susceptible to water stress than established trees. And although you may have heard that citrus trees are drought resistant, they have shallow roots and are actually among the least drought-resistant fruit trees.
So what actions should you take in a drought year?
Water early. In a drought year, the root zone will dry out earlier so you have to start watering earlier. Adequate irrigation early in the season is more important than water later. Trees grow more slowly later in the season, and most trees will have already borne fruit. They may lose their leaves and set few flower buds, but they will survive. In extreme drought, deep watering once or twice in the spring and early summer will likely keep trees alive. However, these trees may not bear fruit.
Mulch your soil. Keep soil moisture from evaporating by applying a generous layer of mulch. Mulching also minimizes weeds that compete with your trees for water. Organic mulch will increase soil fertility and the soil's ability to hold water. Apply mulch to moist soil. If your garden has already dried out quite a bit, water first, then mulch.
Keep your trees small. The smaller the tree, the less water it will need. Home gardeners rarely need all the fruit that a mature standard or semi-dwarf tree produces. Smaller trees are also easier to manage. Thin stone fruits, apples and pears when they have the diameter of a quarter, keeping only about half as many fruits as you normally would. Fewer fruits require less water, and you have a better chance of getting good quality.
Prune hard. During the dormant season, cut back your fruit trees by about one-third. Then prune during the growing season to minimize growth. The goal is to limit the number of leaves the tree is trying to support. You will sacrifice fruit, but your tree will survive on less water. When you prune, paint the newly exposed limbs and trunk area with a mix of equal parts light-colored interior latex paint and water.
Water the right trees. Among common fruit and nut trees, almonds, figs and olives are the most drought-tolerant. Nectarines, peaches and citrus are the least tolerant.
Grow healthy soil. Keep adding amendments. The more organic matter in your soil, the more water it will hold. Healthy soil holds up to five times as much water as depleted soil.
Workshop: Napa County Master Gardeners will hold a workshop on “Let's Talk Rose Care for Spring and Early Summer” on Saturday, May 23, from 10 a.m. to noon. Join in the discussion about spring and early summer rose care, issues and solutions. We will talk about integrated management for common pests and diseases and how to keep roses healthy even during our current drought and water restrictions. Location: University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Online registration (credit card only)
Mail-in registration (cash or check only)
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( 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.
My ‘Meyer' lemon tree was a casualty. I was stumped as to why it didn't survive as I had faithfully covered it every night. I have since found out that covering your plant is not the total answer to frost protection.
To minimize frost damage, try to choose plants that are not frost sensitive. If you simply must have a plant that is frost tender, at least put it in a location that gives it a fighting chance in cold weather. Identify your garden's warmest sites, perhaps an area with western or southern exposure or a spot against a western-facing wall. The wall stores the sun's heat during the day and releases it at night.
Fertilization and pruning also play a role in frost tolerance. Discontinue fertilizers and refrain from pruning after late August. The nitrogen in fertilizers promotes growth, as does pruning, and this tender new growth is sensitive to low temperatures. Citrus trees are an exception. Consult resources like Sunset's Western Garden Book to understand your plant's fertilizer requirements going into the cold months.
I was not aware of how important it is to keep plants watered during weather extremes. A thirsty plant is already stressed. Add a frost and you have a deadly combination. If nature gives us rain in winter, your plants are hydrated and less stressed. No rain? Get out there and water your landscape.
Succulents are an exception and should be somewhat dry going into a frost. I had turned off my sprinkler system and was thoughtless as to my garden's condition. When cold weather arrived, my water-deprived and stressed garden was hit hard.
Keep the soil clear under your plantings. Mulch or debris under the plant prevents the soil from absorbing daytime heat, so it remains cold. Keeping soil cleared also helps to prevent disease and discourage pests. Cleared soil warms up faster and can release that warmth back into the air. Replace mulch in the late spring or early summer to help keep the shallow roots cool and reduce water loss in hot weather.
Frost injures plants by causing ice crystals to form in plant cells. This makes water unavailable to plant tissues and disrupts the movement of fluids. Frost-damaged leaves appear burned and shriveled and turn dark brown or black.
So how does one prepare for cold weather? Many plants can survive short periods of below-freezing temperatures. You may see some blackened branch ends and dieback but nothing life threatening.
Prolonged low temperatures cause most of the problems. If frost is forecast and it hasn't rained recently, water your landscape. Citrus and other frost-sensitive plants require further protection. Cover these plants with a lightweight, breathable fabric like floating row cover. Other commonly used materials include old sheets or bed covers. Build a structure to keep the cover from touching and burning the plant.
Tomato frames can provide support for frost cloth. Remove the cover during the day so plants can enjoy the sunshine and air. Recover at dusk. Lighting under the covers will supply heat, but make sure to use only lights and extension cords rated for outdoor use.
If you didn't heed the frost warnings, you may now have damaged plants. Resist pruning the dead or damaged foliage as it will protect the plant from further damage. Force yourself to leave the plant alone until it sends out green shoots. You have been forewarned. The frost months are fast approaching so make preparations now.
Workshop: Napa County Master Gardeners will host a workshop on “Saving and Sowing Seeds to Sustain School Gardens” on Wednesday, January 21, from 3:30 p.m. to 5:30 p.m. This workshop will introduce basics of seed-saving with children, along with simple activities for seed exploration and observation. We will demonstrate the best seed sowing methods. Participants will start late spring/early summer crops, which Master Gardeners will tend until they are ready to leave the greenhouse for school gardens. Location: Connolly Ranch Education Center Greenhouse, 3141 Browns Valley Road, Napa. This workshop is free but registration is encouraged. Click here to register: http://ucanr.edu/2015schoolgardens
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( 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.
The University of California is a land-grant university. The first campus, in Berkeley, had a strong agricultural focus. In 1907, the university established a research farm that became the U. C. Davis campus, and the Citrus Experiment Station in Riverside, the foundation for the U.C. campus there.
Counties wanting to participate in C. E. had to allocate funding for it. They also had to organize farmers into Farm Bureaus .Each community would get a farm advisor to work with the Farm Bureau. In 1913, its farm advisor in place, Humboldt County became the first county to join Cooperative Extension. Seven more counties, including Napa, joined the partnership in 1914.
U.C. Cooperative Extension is part of the University of California's Division of Agriculture and Natural Resources. It encompasses 200 C.E. advisors, 130 specialists, 57 county offices and nine research and extension centers. The Master Gardener program, including the active Napa Valley branch, operates under the purview of U.C. Cooperative Extension.
Farm advisor Dean Donaldson organized the U.C.C.E. Master Gardeners of Napa County in 1995. The group will celebrate its 20thanniversary next year. It continues to expand outreach to home gardeners in Napa County.
Napa County has been agriculturally important since before it became a county in 1850. Grain was the main crop while California was still part of Mexico, with wheat grown along the Napa River. By 1880, Napa County produced wheat, barley, wool, wine and fruit and shipped these crops across the country. By the beginning of the 20th century, there were an estimated 500,000 fruit and nut trees in the valley, including apples, cherries, apricots, peaches, pears, plums, olives, almonds and walnuts. At the time, prunes and grapes were the largest crops.
The ‘Hartley' walnut and ‘Boysenberry', both developed in Napa Valley, are stars of our county's agricultural history. John Hartley emigrated from England to California in 1884, moving to Napa in 1904. He purchased land with Persian walnuts, known for producing large crops of heart-shaped walnuts with mild flavor. At the 1915 Panama-Pacific International Exposition in San Francisco, judges awarded the walnut a medal for exceptional quality and named it the ‘Hartley' walnut.
In the 1920s, Rudolf Boysen experimented with crossing various berries. In 1923 he crossed a blackberry with a loganberry and a raspberry to create the Boysenberry. In the 1930s, Boysen sold the rights to his fruit to Walter Knott in Southern California, who later would found Knott's Berry Farm. The fruit was first sold commercially in 1935.
To celebrate the centennial, you are invited to participate in a science project. On May 8, the 100th anniversary of the Smith-Lever Act, Cooperative Extension invites all Californians to become citizen scientists for a day and help collect scientific data.
To participate, simply look around your home or workplace and record your observations on any or all of these three questions: How many pollinators do you see? How do you conserve water? Where is food grown in your community? To record your observations, visit http://beascientist.ucanr.edu.
Workshop: Napa County Master Gardeners will lead a workshop on “Container Gardening and Succulents” on Saturday, May 17, from 9:30 a.m. to 11:30 a.m., at the Senior Multi-Use Center, 2185 Elliott Drive, American Canyon. Grow gardens that are mobile. Discover the best containers, soil and locations for your plants to prosper. Gain confidence to work with unfamiliar types of plants. Online registration (credit card only); Mail in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( 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.
Napa County Master Gardeners welcome the public to visit their demonstration garden at Connolly Ranch on Thursdays, from 10:00 a.m. until noon, except the last Thursday of the month. Connolly Ranch is at 3141 Browns Valley Road at Thompson Avenue in Napa. Enter on Thompson Avenue.
Although each of these claims may be true, for me the answer is simpler: I grow food for my table. As I have become a more knowledgeable vegetable gardener, I have wanted to increase the variety of crops I grow and to harvest year round.
Plants are adapted to grow at specific temperatures. Some annual vegetables prefer warm weather; others perform best when it’s cool. Warm-season plants grow best in daytime temperatures of 65°F to 95°F. They thrive when night-time temperatures stay above 50°F. Most of them tolerate high temperatures but are damaged or killed by frost. Cool-season crops prefer cooler soil and air (55°F to 75°F), perform poorly when temperatures are high, and tolerate or are improved by frost.
When researching average temperatures for Napa County, I found some useful graphs on the Weather Channel’s website (www.weather.com). From May to October, our average lows range from 49°F to 55°F, while average highs for the same months are 76°F to 83°F. The months of November to April see average lows of 39°F to 45°F degrees, and highs of 57°F to 71°F. If our weather is not too extreme, we can accommodate cool-season vegetables six months a year and warm-season vegetables during the other half.
So growing vegetables year-round in Napa County is just a matter of timing: growing the right plants at the right time.
Year-round vegetable gardening uses soil intensively, so maintaining fertility is critical.
Soil is comprised of four principal components: minerals, organic matter, air and water. Minerals and organic matter make up about half of the volume of typical California soils, with minerals being by far the largest part. Soil minerals are basically decomposed rock. The size of the particles determines whether your soil is sandy (large particles), loam or clay (small particles).
Organic matter consists of decomposing plant and animal residue, living soil organisms (earthworms, fungi, bacteria) and the substances they synthesize.
The other half of the soil’s volume is the pore spaces between the solid particles. In soils with ideal moisture content, the pore spaces are about half water and half air. Typical soil by volume will be about 45 percent minerals, 25 percent water, 25 percent air and 5 percent organic matter.
Soils can be coarse and sandy or fine and clay-like. Their texture reflects the mineral content, which is difficult to alter. However, increasing the organic matter in sandy or clay soils changes the way the soil aggregates, or clumps, and improves the conditions for growing plants.
Although the living organisms in soil comprise a small percentage of its volume, mounting scientific evidence suggests that these organisms play a significant role in helping plants fight disease and pests. Many soil microorganisms live in beneficial relationships with roots. These organisms digest organic matter over time and need air and moisture to survive. Even when you don’t have a crop in the ground, you need to provide an environment that encourages this soil life. In a year-round vegetable patch, you should add compost or other organic amendments at least twice a year, or each time a new crop is planted.
Our California soils tend to be low in nitrogen, a major nutrient for growing plants. Your soil may also be lacking in other nutrients. Year-round vegetable gardening can quickly deplete soil nutrients. If your organic amendments are not relatively high in nutrients, you will need to fertilize several times a year. Although you can use synthetic fertilizers, they can harm the natural soil life. Use all fertilizers carefully, following package directions and never using more than recommended.
Plants interact with soil in different ways. Just as farmers do, home gardeners should rotate crops to prevent soil-borne diseases from getting established and to foil pests that prefer specific crops.
So here’s 12-month gardening in a nutshell: plant the right plants for the season;feed the soil with organic amendments; use fertilizers as needed; and rotate plants. Then proceed to enjoy homegrown food year round.
Workshop: Napa County Master Gardeners will conduct a workshop on “Success with Veggies All Year Long” on Saturday, January 25, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Learn how to keep your garden soil healthy and productive, find out which vegetables to plant in what months, and be introduced to many reliable resources. Online registration (credit card only)Mail in registration (cash or check only)
Napa County Master Gardeners welcome the public to visit their demonstration garden at Connolly Ranch on Thursdays, from 11:00 a.m. until 1 p.m., except the last Thursday of the month. Connolly Ranch is at 3141 Browns Valley Road at Thompson Avenue in Napa. Enter on Thompson Avenue.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( 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.
I remember ending last month’s to-do list with a promise that December’s garden to-do list would be shorter. What was I thinking?
There is actually a lot to do in the garden in December. If you planned ahead and were industrious in late summer, you are probably harvesting Brussels sprouts, cabbages, broccoli, kohlrabi and kales. Harvest individual Brussels sprouts from the bottom, or cut off the entire stalk and store somewhere cold while you use them. We have two upright, full stalks of bright green Brussels sprouts resting in our cool pantry, and I pop off a potful of sprouts as needed.
Beets, carrots, scallions, radishes and lettuces of all varieties are easy to grow in fall and winter. Micro-greens and Asian greens also thrive in cool and even cold weather. It is easy to fill your salad bowl from the garden at this time of year.
When the weather gets really cold and my lettuce freezes, I have found that if I do not touch the leaves until they thaw, they will often be fine. Touching them damages fragile cells, which causes the leaves to deteriorate when they thaw in the morning sun.
Carrots and radishes can be sown now, as can English peas, sugar peas, sweet peas and spinach. Perhaps you are harvesting some of these crops now if you planted them in late summer. Pomegranates seemed to ripen a little early this year, but you might have a few of those left to pick, too. Complete your olive harvest if you haven’t already. University of California Extension has instructions for curing olives in several ways.
You can plant fava beans now. They are a popular cover crop in Napa Valley, preventing erosion during the winter rains. Plowed into the soil in spring, they contribute nitrogen and biomass, replenishing fertility.
However, if you grow fava beans for the table, wait to harvest them until the beans swell inside the fuzzy green pods. After shelling them, you can eat the beans raw or cooked, peeled or unpeeled. Italians enjoy young fava beans peeled and raw, with olive oil and salt for dipping, crusty bread and a glass of red wine. You can also let the pods mature on the plant and harvest the dry beans to use for soup.
If you plant radishes right now, you may have some fast-growing varieties ready by Christmas or New Year’s. Consider crisp red ‘Cherry Belles’ or long white daikon types. Smooth- or curly-leaf spinach varieties, chard, parsley, and sets of shallots and garlic can still go in.
Because a gardener’s work is never done, you will already find transplants at the nursery for spring harvests of broccoli, cabbage, cauliflower, lettuce and arugula. Shop for rhubarb and artichokes early; nurseries offer them on a first-come, first-served basis. When the supply runs out, you won’t see them again for a year.
Nurseries may still have a few bulbs for spring bloom. Their blossoms are lovely in the garden, but consider forcing bulbs for indoor color, too. Many bulbs are sold with directions for forcing. Some instructions may recommend chilling bulbs before planting outdoors. Follow the directions and enjoy the results.
Get out your floating row covers to extend the harvest of some crops as the temperature drops. You can also use this material to keep aphids and other insect pests off broccoli and cauliflower. If you have done your winter garden cleanup and eliminated piles of debris, lumber, pots and other hiding places for snails and slugs, you won’t find many pests. If you are still finding a lot of slugs, you might need to tidy up the garden a bit more.
December brings more gray days, but it is still possible to have lots of garden color in protected spots and in pots and baskets. If blue or purple flowers cheer you, then head for the pansies and violas. Violas in yellows and oranges make a wonderful contrast in sunny baskets.
Remember to stay off your garden soil when it is wet to avoid compacting it. If you expect to plant bare-root roses, fruit trees or vines this winter, try to get the planting holes dug before heavy rains begin. Lay plastic sheeting over the planting holes to prevent them from getting too wet to work.
Begin pruning your deciduous fruit, nut and shade trees now. Do not prune evergreen shrubs, roses or vines. Pruning evergreens stimulates new growth that could be vulnerable to a cold snap. Cover your compost pile when it rains so you do not drown your hard-working microbes. Bundle up and enjoy our Napa Valley winter. January’s to-do list will surely be shorter.
Napa County Master Gardeners welcome the public to visit their demonstration garden at Connolly Ranch on Thursday mornings, from 10:30 a.m. until noon, except the last Thursday of the month. Connolly Ranch is at 3141 Browns Valley Road at Thompson Avenue in Napa. Enter on Thompson Avenue.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( 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.
