By David Layland, U. C. Master Gardener of Napa County
Climate change, also called global warming, has been in the news lately because of the devastating wildfires in Northern and Southern California. Climate change refers to the rise in average surface temperatures and is due primarily to the use of fossil fuels which releases carbon dioxide and other greenhouse gases into the air.
The gases trap heat within the atmosphere, which can have a range of effects on the environment including rising sea levels, severe weather events, and droughts that render landscapes more susceptible to wildfires.
There are two ways to mitigate the environmental damage done by fossil fuels. The most common way is to reduce the use of fossil fuels—by driving a hybrid or electric car, for example, or using solar or wind power. The second way, carbon sequestration, involves pulling carbon out of the air and storing it in the ground.
I don't drive a hybrid or electric car but I do have solar power. It provides 90 percent of my electricity at home so I've done something toward lowering emissions.
Carbon sequestration is new to me. In researching what I could do to help pull carbon out of the air, I discovered that I'm already using several carbon-sequestration practices in my garden. To some extent, these practices are what organic gardeners have been doing for a long time.
Make compost: One of the primary differences between organic and conventional gardening can be boiled down to a simple change in perspective: Instead of worrying about feeding the plants, we should worry first about feeding the soil. Take care of the soil and the plants will take care of themselves.
By composting all of our food scraps and garden waste, we aren't just providing valuable nutrients for plants. We are providing food for a huge ecosystem of bacteria, fungi and insects, all of which help to absorb carbon from the environment and keep it locked up in the soil. You can add cardboard and other paper-based waste to your compost, too. High-fiber composting works, and it's another way to lock up some CO2.
Don't dig: Many old-school gardeners may scoff at the idea of no-dig gardening, but there are good reasons to abandon the rototiller and dig only when necessary. No-dig gardening could have a significant impact on preserving soil carbon.
By slowing down the rate of decomposition in the soil, you help increase soil carbon and save yourself some labor. More than 15 years ago I purchased a rototiller because I thought I “needed” one for my garden and vineyard. I used it for a few years, until I realized I didn't need it. It sat under a tarp for a few more years until I found a new home for it.
That was an expensive lesson. Not using a gas-powered rototiller also means you are not using fossil fuels and are not spewing pollutants into the atmosphere. And you're not killing the hard-working earthworms that are improving your soil health.
When you refrain from tilling, you avoid exposing the soil to excess oxygen and sunlight. You can achieve the same thing by mulching, but an even better way is to plant cover crops, or so-called green manures, which can later be hoed in or mowed down. Doing so will add carbon to the soil while helping the root system keep soil in place. Cover crops also provide a habitat for soil life when you don't have edible crops.
Lose the lawn: This recommendation was easy for me. Before my wife and I moved to Napa, we had a lawn that was more than an acre and, of course, we had a riding lawnmower. After four years of mowing this lawn I never wanted to have another one.
The standard lawn requires a considerable amount of costly maintenance, water and chemicals if you want that green carpet to look perfect. There are many environmentally-friendly alternatives to a lawn. In Napa, I opted for decomposed granite. There's no maintenance and the permeable surface allows water to reach the soil. I added a few drought-tolerant plants for color and trees to shade the house. And I'm saving fossil fuels by not using a gas-powered lawnmower.
Grow lots of stuff (except a lawn): To store the maximum carbon, always keep the soil surface covered with growing things such as trees, turf, vegetables, flowers and cover crops. The more variety, the better. Grow plants with deep, extensive root systems and coarse, woody roots; shallow, fine roots decompose too easily. If I had it to do over again, I might not use as much decomposed granite as I did. At the time, I was focused on lawn alternatives, not on carbon sequestration.
So there you have some tools for carbon sequestration at home. Now go out there and do your part to fight climate change.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Pruning” on Saturday, January 13, from 10 a.m. to noon, at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Why do we prune roses? Is winter the only time to do it? What will happen if we don't? Should hybrid teas be pruned differently from floribundas? Join the Master Gardener Rose Team at this popular forum where resident experts will answer your questions about basic rose pruning fundamentals with research-based information. Topics include rose types, how and when to prune, what tools to use and how to care for them, safety and sanitation. No doubt each Master Gardener will have some suggestions for new plantings, too. Online registration (credit card only);Mail-in/Walk-in registration(check only or drop off cash payment).
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.
This year has been one of the hottest on record, and next year is likely to be even hotter. As the temperature rises, gardening can become increasingly challenging. There are a few easy things you can do to help your garden beat the heat this summer.
Typically, the first sign of a plant's heat stress is wilting. No need to panic; immediate watering usually results in a quick rebound. If the plant continues to suffer, however, you will begin to see brown areas and dropped leaves. At that point, the plant may be permanently damaged and require extra care.
Provide the stressed plant with water and shade if possible. Pay special attention to container plants, as they not only get hotter but can be more difficult to rehydrate. Very dry container soil may resist absorbing water at first. You may need to water repeatedly to rehydrate it.
Regarding in-ground plantings, your soil will partially determine how well your plants stay hydrated. Sandy soil drains quickly, whereas clay soil (common in Napa County) retains water, possibly too much for your plants.
The optimal soil type is somewhere in between, rich in humus. Amending your soil with compost or manure will help change its structure to one that is healthier for your garden.
When planning for hot weather, consider that a plant does not have to be in direct sunlight to suffer from heat. A plant may become stressed if the air or soil around it reaches extreme temperatures.
Wind can also be a problem. Despite what common sense or personal experience may tell us, wind will not help your garden stay cooler on a hot day. While a breeze may bring relief to the gardener, it draws moisture from plant leaves, increasing their rate of dehydration.
The key to preventing such problems is proper watering. Where possible, install drip irrigation. The slow, steady application of water will reduce the likelihood of water stress. Drip irrigation also encourages plants to grow deeper roots, allowing them to find water that might otherwise be inaccessible.
Most plants also benefit from mulch. A thick mulch around the plant helps keep soil cool and slows evaporation. Even container plants benefit.
I do a lot of container gardening, and I water my containers by hand. When I know the day will be hot, I prepare my plants with an extreme soaking. During extremely hot periods, I rarely worry about overwatering anything except cacti and succulents. However, that's not impossible, so check your container soil regularly.
Be aware that hard surfaces absorb heat, raising temperatures around them as the day progresses. Light-colored containers reflect sunlight, potentially increasing the amount directed at your plants. These features can be used to your advantage in shady areas or during cool seasons but can turn deadly during the summer.
I recommend treating plant labels with a skeptical eye. Many times I have planted something that the label indicated was suitable for full sun, only to watch it shrivel to a crisp in the Napa heat.
Fertilizer can dehydrate a plant, making it more vulnerable to high temperatures. Before fertilizing, be sure the plant is well hydrated and showing no signs of heat stress. I typically wait to apply fertilizer until the cool of the evening.
If you experience significant challenges in a certain part of your garden, consider using drought-tolerant, low-maintenance plants such as succulents, cacti and California natives.
Salvias are one of my personal favorites. I have heard them referred to as "the only truly drought-tolerate plants" (other than cacti and succulents, of course). Once established, which may take about a year, they will have deep roots that help them access extra water when needed. The family is diverse, and nurseries offer salvias with a variety of growth habits and flower colors.
Finally, don't forget about self-care. Gardening can be strenuous, and you can become dehydrated more quickly than you expect. Start garden work early in the day, and never forget to water yourself!
Free Guided Tree Walk: Meander through the park as guides talk about its history and share information on 41 different trees. Wear comfortable shoes. Water and restrooms are available. All are handicap accessible. The book Trees to Know in Napa Valley will be available for $15, cash or check only. Tours depart from Fuller Park, 560 Jefferson Street, Napa. ONLINE REGISTRATION or call 707-253-4221. Walk-ins are welcome but you will be guaranteed a complimentary map if you register at least 48 hours in advance.
Do you want to become a UC Master Gardener of Napa County? To apply, you must attend an information meeting. For meeting dates, locations and times, or to learn more about the program and volunteer commitment, visit the UC Master Gardener of Napa County website.
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.
By Denise Levine, U. C. Master Gardener of Napa County
October is a colorful month filled with ripe but dwindling summer produce. Tomatoes are at their reddest, hoarded and appreciated; peppers are hot crimson and sweetly gold. Cucumbers are finally big, but the vines are slowing down. Squash and melon plants have sprawled and are looking spent and ready to come out.
But the first peas are big enough to pick, figs both black and white are ripe for the picking, and days are cool enough that lettuce and radishes are beginning to thrive again.
Pull out your bare-root fruit tree catalogs or call local nurseries for lists of the trees they will be offering this winter. Take advantage of October's mild days to prepare holes for the apple, peach, plum and pear trees you want to purchase bare-root in January, when the soil may be too waterlogged. You will thank yourself in January if you do this work now. Then your rainy-season planting will be easy and successful.
October is also a good month to order compost and have it delivered. Heavy trucks will compact softened, rain-soaked soils and leave you with deep ruts to remember them by.
Are we getting at least an inch of rain a week this month? If not, continue watering shrubs and plants. Feed citrus and other shrubs such as azalea and camellia. They are all prone to chlorosis (yellowing) from iron deficiency. A trip to your favorite nursery or garden center for chelated iron may be in order.
Yellowing in other leafy plants is often a sign of nitrogen deficiency. Diluted fish emulsion, applied with a watering can, will typically “green up” leafy plants and give them a new flush of growth. But as winter approaches, the Master Gardener Month-to-Month Guide recommends feeding the vegetable garden one more time with an ammonium form of nitrogen to reduce leaching when the rains come. Your garden center can show you the options.
Are you lucky enough to have a big garden or good-sized beds? Are you replenishing this soil with cover crops yet? If you now have bare beds that produced melons, corn or other crops all summer, consider planting a cover crop to grow through winter.
Cover crops, also called green manures, protect your soil from erosion caused by winter rains. They pull up minerals deep in the soil, making them accessible to future crops. And they serve as a living mulch, smothering weeds, creating habitat for worms and other soil-forming organisms and providing pleasing visual texture through cold gray months.
For your green manure, consider fava beans, golden mustard with its sunny yellow blooms, or oats or barley planted with clover. University of California Cooperative Extension has helpful information on cover cropping for the home gardener (http://ucce.ucdavis.edu/files/filelibrary/5842/25997.pdf). Plant cover crops now so they can grow through winter. In spring, till them into the soil. Three weeks later, the green biomass will have decomposed and the beds will be ready to plant.
Clean up your vegetable and flower garden this month and eliminate hiding places for pests and diseases. Rake up and discard fallen fruits and vegetables and spent annuals like zinnias and sunflowers. Start a new compost pile. Making these efforts now will mean fewer hiding places for snails and slugs and new soil for your garden when you need it next spring.
Now is a good time to dig up and divide crowded perennials like Shasta daisies, agapanthus, nepeta, daylilies or echinacea. Give extra plants to friends for their gardens, or expand your own beds.
If your dahlias look unhappy, let them die back and then gently dig them up and store them where they will not freeze. Keep them dry; do not wash them off or they could rot or become diseased before replanting in spring.
Chrysanthemums are still in their full autumn glory. Whether you cut them by the armfuls for indoor bouquets or enjoy them outside, examine them closely for aphids. If you spot these pests, wash them off with a good blast of water from your hose or spray bottle. Repeat diligently until you no longer spy them.
Continue planting your vegetable garden. Sow seeds of fava beans, carrots, spinach, lettuce and arugula, and plant seedlings of cabbages, Brussels sprouts, broccoli and cauliflower. All of these brassicas appreciate a floating row cover to thwart moths, aphids, birds and critters.
Native Plant Sale: U.C. Master Gardeners of Napa County will have an information table at the California Native Plant Society Napa Chapter's plant sale on Saturday, October 15, and Sunday, October 16, from 10 a.m. to 4 p.m., at the Martha Walker Native Garden in Skyline Park in Napa. Volunteers from both organizations will help you choose the right native plants for any spot in your garden. The preview party for CNPS members and guests is Friday, October 14, from 6 p.m. to 8 p.m., at Skyline Park.
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.
A tree's heat requirement is the number of hours it needs between bloom and maturity at a temperature above 55°F. ‘Washington' oranges, for example, need 8,000 hours. Perhaps more important, you need to consider the cold hardiness of your choice. Popular citrus, in order of most hardy to least hardy, would include mandarin orange, sweet orange, grapefruit, lemon and lime.
If your property experiences frost, one strategy is selecting a citrus variety that ripens early. 'Satsuma' mandarins are the most cold-hardy citrus and the earliest bearer. They do well in areas that are normally too cold for citrus, and the foliage survives temperatures down to about 22°F.
Spring is the best time to plant citrus in Napa County, after the threat of frost has passed. This schedule gives the tree's roots time to establish before the onset of cold weather. Choose your site carefully, preferably a protected area away from wind with at least six hours of sun each day. When the winter sun is low in the southern sky, the tree will appreciate placement near a sidewalk or wall that radiates heat.
Mulching around your citrus in winter may not be a good idea. Research shows that the soil retains more heat when allowed to absorb daylight sun. Replenish your mulch in the spring.
Cold air flows downhill, so avoid siting your tree in a low spot or on top of a windy hill. You can also protect your tree from wind by espaliering it against a wall or fence. Citrus trees can also be planted in containers that can be moved to a warm spot in winter, but pots are a temporary arrangement. Your citrus tree will need a larger pot every couple of years.
Fertilize mature citrus with nitrogen monthly from April through August. Feed from November through January with a citrus fertilizer, such as 0-10-10. Trees in containers require less fertilizer. Citrus occasionally suffer from a deficiency of micronutrients, such as zinc or iron. As new growth emerges in spring, add zinc or iron sulfate to the soil or try a foliar application of chelated zinc or iron. Iron will increase the juiciness and size of the fruit.
Maintaining a good fertilizing program helps your tree resist fungal diseases. However, over fertilizing will produce excessive foliar growth, making the tree susceptible to other disorders such as bacterial blast. Use insecticidal soap against the common insects that tend to bother citrus, such as scale, leaf miners and mites. Blast aphids with a strong spray of water.
When cold weather arrives, be ready for frost protection. A citrus tree's tolerance for frost is related not only to variety, but also to maturity and the level of hardening it has experienced. Young trees are especially vulnerable. The amount of damage a tree and its fruit suffer depends on the length of time the temperature remains at or below the threshold for that variety.
For example, if the temperature remains at 25°F for four to five hours, 60 percent of the fruit may freeze. Ripe oranges, grapefruits and mandarins start to freeze at 27°F to 28°F and lemons at 29°F to 30°F. With this information in mind, you can understand the value of frost-protection fabric, which affords a few degrees of protection. I have seen homeowners in Napa who have risen to the challenge, devising tenting that is practically an art form.
Water your tree before the temperature dips. A well-hydrated plant is more capable of withstanding frost damage because moist soils hold heat better. Outdoor tree lights (not LEDs)can be wrapped around your tree to provide extra warmth. Wait until spring to prune any frozen limbs.
Free workshops: Napa County Master Gardeners will lead a workshop on “Soils, Mulches & More” on Monday, September 29, from 6:30 p.m. to 8:30 p.m., at the Yountville Community Hall, 6516 Washington Street, Yountville. Learn the importance of soils, amendments and mulching. Understand basic landscape design and plant grouping. Napa County Master Gardeners will assist with another workshop on “Perfect Plant Picks” on Monday, October 6, from 6:30 p.m. to 8:30 p.m. in the same location. See how a drought-tolerant garden can be colorful and beautiful. Dozens of plants will be on display, including California natives. Both workshops are free but registration is required. To register, call 707-252-4188 X116 or e-mail frances@naparcd.org.
Workshop: Napa County Master Gardeners will lead a workshop titled “Be Successful with Citrus” on Saturday, October 11, at the American Canyon Senior Multi-Use Center, 2185 Elliiott Drive, American Canyon and on Saturday, October 18 in Calistoga at the Community Room, 1307 Washington St. Both workshops are from 9:30-11:30. Get the information you need to succeed with your new or mature citrus trees. Learn about choosing varieties, planting, fertilizing and protecting from frost.Online registration (credit card only); Mail-in registration (cash or check only).The workshop will be repeated on Saturday, October 18, from 9:30 am to 11:30 am. Register online for the Calistoga workshop.
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.
- Author: Denise Seghesio Levine
Time for last-minute holiday shopping, and if gardeners are on your list, you are in luck. Gardeners are some of the easiest people to shop for. There is always something a gardener can use.
Gardener-friendly finds range from tiny seed packets, garden clogs and bare-root roses to big-ticket items like greenhouses. So if you are still pondering last-minute gifts, consider some of these for inside and out.
More gardeners every year are embracing old-fashioned culinary skills and learning how to preserve their harvests. Canning jars, canning supplies and cookbooks about preserving and canning are more available than ever and welcomed by new and seasoned canners alike. Responding to the renewed interest in home preserving, merchants now stock beautiful jars, BPA-free canning lids and a plethora of pickling and preserving books. Little items like decorative labels for pantry jars are fun and useful, too.
For gardeners and cooks who are ready to move beyond basic water-bath canning, consider surprising them with a pressure canner. These devices process low-acid foods that cannot be safely preserved by the water-bath method. For example, you can process plain tomatoes with salt and lemon juice in a water-bath canner, but you need a pressure canner to process tomato sauce with onions or mushrooms. Pressure canners are easy and safe to use and expand the gardener's ability to safely stock the pantry with produce from the garden. Regardless of what kind of home preserving you or your gardening friends do, follow the directions and processing times recommended by the USDA onits website and in its publications.
Compost buckets for collecting kitchen waste are now as fanciful and decorative as cookie jars—a good choice for any home composter tired of fruit flies hovering over the scraps on their way to the compost pile. Sure, there are utilitarian metal buckets, but you can also find ceramic compost keepers in a wide palette of colors, or more whimsical buckets that look like heads of romaine lettuce. Simple compost keepers are just good-sized lidded containers, while more expensive versions have replaceable charcoal filters to help keep odor down.
Compost thermometers can help dedicated composters monitor the temperature of their compost piles. Keeping a pile hot is essential for breaking down pathogens and killing weed seeds in compost. You can find these thermometers in garden-supply and hardware stores. For an aspiring composter, consider purchasing a home compost system. There are many types to choose from.
Every gardener can use another good reference book in his or her library. Noteworthy possibilities include one updated classic and a new local publication.
Sunset has recently reissued its popular Western Garden Book. First published 80 years ago, this gardening bible has been completely revised and updated for the ninth edition. Sunset has refreshed and expanded its compendium to meet gardeners' evolving needs. This ninth edition includes new sections on edible landscapes and fire-wise gardens, as well as information on wall and roof gardens.
Field Guide to Mushrooms of Western North America by R. Michael Davis, Robert Sommer and John A. Menge (University of California Press) will be treasured by wild-mushroom enthusiasts. Davis teaches plant pathology and mushroom identification and culture at the University of California at Davis. Sommer and Mengeare emeritus professors at Davis. The three have compiled primary descriptions and illustrations of 300 species of mushrooms, plus text-only descriptions of many more. For “shroomers,” this is a helpful new addition to the field-guide section of the bookshelf.
Of course, a wonderful gift for Napa Valley gardeners is A Month-by-Month Guide to Gardening in Napa County, written by U. C. Master Gardeners of Napa County. For tree lovers or anyone re-doing a landscape, consider Trees of Napa Valley by John Hoffman and illustrated by local Master Gardeners. Hoffman, now deceased, was a professional arborist and Napa resident. You can order both books online at http://ucanr.edu/sites/ucmgnapa/Gardening_Books/Our_Books/.
For gardeners who anxiously await the first hint of spring to start their gardening season, consider a soil thermometer. These devices take the guesswork out of when to plant. Just insert the thermometer into the soil as directed to know if your seeds are likely to sprout, or rot waiting for warmer soil. The same gardeners might also appreciate some floating row cover to extend the season or a mini-hothouse to get a jump on planting.
Seeds and plants make wonderful gifts, too. Illustrated seed packets are wonderful stocking stuffers. You can choose quick-growing crops like radishes for little people, or something exotic for the gardener ready for a new challenge. Bare-root roses and fruit trees are good choices, as are gift certificates to a favorite garden center.
Ask Master Gardeners what they want for Christmas, and quite a few will tell you they would like a truckload of compost. I know that is what I am getting. I just don't know if there will be a bow on it.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners (http://cenapa.ucdavis.edu) 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, 707-253-4221, 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?
