- Author: Help Desk Team
It's summertime! Our gardens are in full swing, tomatoes are beginning to ripen, berries are mostly done, and everything is lush and green. But beware, your plants can sunburn just like you. Sometimes we all need a little break from the heat, especially in the central and eastern portions of Contra Costa County where daytime temps regularly exceed 90 degrees.
Sunshine is necessary for plant growth, but too much can stress plants. Shade cloth (also called shade fabric) can block excessive sunshine and heat and will:
• Lower temperatures
• Reduce heat stress
• Prevent sunburn
• Reduce evaporation from the soil and the plant
• Reduce water needs
• Extend the growing season
• Expand the type of plants that can be grown
Selecting shade cloth
Shade cloth can block between 20% and 90% of the sun's rays reaching your garden beds, also called the transmission rate. A 30% shade cloth will reduce the sunlight reaching plants by 30% and will let 70% of the sun's rays in. The transmission rates will be shown on the product at the store. Delicate seedlings and cooler season plants (lettuce and spinach) will benefit from more shade (50–60% shade cloth), while sun-loving plants like fruits, tomatoes and peppers would do better with less blockage (20–40% shade cloth). Shade cloth is sold two ways: from a roll with a predetermined width and a length that you choose, or in pre-cut triangle and rectangle shapes. Shade cloth also comes in a variety of colors—black, brown, green, shades of beige, white, and sometimes less-common colors.
Installing shade cloth
Shade cloth can be installed several ways, depending on your garden layout. It can be spread over PVC hoops, also called hoop houses, or other PVC structures and secured with zip ties, ropes/twine, bungee cords, etc.
A triangle or rectangular piece can be installed like a sail attached to building edges or poles over the garden bed in a tent-like structure.
A DIY Frame can be made from fencing, vegetable cages, etc. and shade cloth can be draped and secured over the frame.
Be sure to attach shade cloth securely so that it does not flap or slide out of place because that can damage plants.
The vast majority of commercially available shade cloth is made from petroleum products like polypropylene or polyethylene. You may find shade cloth made from natural fibers such as jute, bamboo, sea grass, etc. but this is less common.
Give yourself and your plants a break from the heat this summer and for many summers to come by investing in some shade. It can help you use less water, prevent sunburn and heat stress, and extend your growing season. Enjoy your summer!
For more information about shade cloth in the garden, see this link: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=55005
Help Desk of the UC Master Gardeners of Contra Costa County (DLB)
- Author: Help Desk Team
You really do not want voles (also called meadow mice) moving into your garden. They are larger than a house mouse or deer mouse but do not quite reach the size of an adult gopher or rat. Although it is said that they can mature to 5–8 inches long including the tail, they are most commonly on the smaller side of the range. With their charming pudgy shape, beady black eyes, small ears, soft gray/brown fur, and rather short and oddly furry tail, their appearance could be thought of as somewhat cute or endearing. That is, until you experience how quickly they can lay waste to your beloved garden.
When they are not ravaging your garden plants, these rodents spend much of their time hiding in their burrows. They are most likely to be seen during the cooler parts of the day such as dawn and dusk, when they dash from one burrow to another, or scurry from dining on your favorite plant into the safety of their burrows. The burrows have openings that are 1 ½ to 2 inches wide. There are often obvious runways from the burrows where soil is trampled down by their repeated scampering back and forth. Voles will happily burrow into both mulch and soil, and where there are dense weeds or long grasses (a favored habitat), voles will create distinctive tunnels through the vegetation.
Vole populations regularly go through cycles of low to high numbers. Their numbers generally peak each 3 to 6 years or so, but don't count on being able to guess when the next vole invasion will occur. These cycles are not predictable. Their numbers can increase to staggering amounts during a population explosion, soaring to as many as several thousand per acre.
If you have voles in your garden, you already know they eat a very wide variety of plants. Unlike rats and mice that are out and about wreaking havoc at night, voles are active both day and night, and year-round. Also, unlike rats and mice who have favorite foods and tend to go after sweet, ripe fruits and the most succulent vegetables, voles are not terribly picky. They will eat a wide variety of plants including zucchini, cucumber, green bean, tomato, and artichoke. Basil, dill and parsley are some herb plants that may be there one day and gone the next. Flowers such as marigolds, cosmos, yarrow, and sunflower are also part of their menu plan.
Voles do take an occasional break from their feeding frenzy to breed and can have 5 to 10 litters of offspring each year. They can have 3–6 young at a time. One redeeming quality is their short lifespan of just a few months to a year, and the fact that after a season of super high numbers, the population tends to go back to normal.
There are several effective control methods such as habitat modification (make the area less hospitable to them), trapping (setting many, many mouse traps), and exclusion (creating impassable barriers around your garden, your garden beds, or even individual plants).
Vole management
Habitat modification is an effective way to reduce vole damage in the landscape. Remove weeds, heavy mulch, and dense vegetative cover to reduce their food sources and expose them to predators. Voles prefer not to feed in the open so 4-foot buffer strips of open ground can help protect trees or other plants.
Because of the large numbers of voles that can be present during a population explosion, exclusion is often the most important option. Wire hardware cloth with ¼ inch or smaller mesh makes a good barrier if it is at least 12 inches tall. Make sure it surrounds the plants completely and bury it into ground 6 to 10 inches deep. Metal roof flashing, sold in hardware stores, makes a very effective barrier. It comes in rolls with varying widths. Unlike gophers, who dig deep burrows, voles usually dig down only a few inches. They are not very athletic and don't climb or jump very well like rats can, so barriers don't have to be terribly tall to be effective.
Trapping can be effective if vole numbers are low or they are in a small area, but difficult when the population is high. The key is to use many mouse traps at the same time. For detailed directions on how to place traps, see the link below.
Voles are an important part of the natural food chain. They are prey for a variety of predators including hawks, crows, owls, snakes, raccoons, bobcats, foxes, coyotes, opossums, and domestic cats. They may not keep vole populations adequately controlled near homes because of their reluctance to hunt close to homes.
There are toxic baits available, but care must be taken to ensure the safety of children, pets, and nontarget animals such as the predators listed above. See the link below for more information.
This UC IPM (integrated pest management) link is an excellent source for information on identifying and managing voles:
https://ipm.ucanr.edu/home-and-landscape/voles/pest-notes/#gsc.tab=0
This link will help you determine whether damage to your yard is due to voles, gophers or moles:
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=49119
Help Desk of the UC Master Gardeners of Contra Costa County (SMH)
- Author: Help Desk Team
This post is a rerun from 2023.
Have you noticed tomatoes that have round, water-soaked spots on the bottom? Blossom end rot (BER) is a frustrating problem that can be quite common in vegetable gardens, as it can affect tomatoes, peppers, and squash. You might notice it after a few very hot days. It usually starts on green fruit as a small, discolored spot on the end opposite the stem that might look water soaked. The spot enlarges and tissues dry out, becoming sunken, collapsed, and leathery.
Some tomato varieties, especially paste tomatoes, are affected more than others, but all varieties except cherry tomatoes seem to be susceptible if conditions are conducive. It is more likely to occur earlier in the season when plants are rapidly growing, but it can also show up later in the season when we have hot, dry weather.
Blossom end rot results from a low level of calcium in the fruit and a lack of water balance in the plant. Most of our soils have plenty of available calcium so there is no need to add more. Fluctuations in irrigation and/or heavy application of nitrogen are often the culprits in this condition. To reduce blossom end rot, monitor soil moisture to make sure the root zone neither dries out nor remains saturated. Follow recommended rates for vegetable fertilizers, using organic fertilizers.
Improvement in irrigation practices usually results in the problem going away. Rather than watering on a schedule, you should check the soil to determine its moisture level. Either by digging down into the soil without disturbing the roots or using a moisture meter, check to make sure the entire root zone is moist but not soggy. Use mulch around the plants to help maintain soil moisture, but make sure the mulch isn't right against the base of the plants.
Blossom end rot is not caused by a pathogen, so there are no pesticide solutions.
To reduce blossom-end rot:
• Use cover crops in the off season to increase water-holding organic matter in the soil.
• Irrigate before periods of hot weather.
• Don't disturb the root area.
• Don't over fertilize. Too much nitrogen during the early fruiting period can tie up calcium and make BER worse. Manure, especially poultry manure, can make it worse.
Vegetables affected by blossom end rot are still edible if they haven't begun to get moldy. Just cut away the discolored area.
More information about blossom end rot:
http://ipm.ucanr.edu/PMG/GARDEN/VEGES/ENVIRON/blossomendrot.html
Information about growing tomatoes in the home garden: https://anrcatalog.ucanr.edu/pdf/8159.pdf
Help Desk of the UC Master Gardeners of Contra Costa County (SEH)
- Author: Help Desk Team
Earwigs are one of the most common pests in our gardens. There is a lot to learn about them besides knowing how to prevent the damage they cause.
Fun facts about earwigs:
- Their name probably comes from myths surrounding these insects:
- They sometimes enter peoples' ears when they are sleeping and they sometimes burrow into the brain
- The forceps appendages at their rear ends look like tools to puncture ears for earrings
- The expanded wings of earwigs have the shape of human ears
- The common and abundant earwigs in our gardens weren't even in California 100 years ago.
- Roald Dahl, author of children's books, has a character in George's Marvelous Medicine that urges the grandson to eat a ‘big fat earwig' and tells him how to do it so it wouldn't grab his tongue with the ‘sharp nippers on its back end.
- Roald Dahl also mentions earwigs in James and the Giant Peach where the characters find an earwig inside the giant peach.
- Under their hard, shiny wing covers, they have remarkably large and complex flight wings that spring from folded to flight without muscles. (These wings expand to 10 times larger than when folded.)
- Female earwigs watch over their eggs and newly hatched young, protecting them and keeping them clean until they are old enough to fend for themselves.
Did you know?
- Earwigs are important predators of aphids, mites, nematodes, and other small insects and their eggs.
- Research from Washington State University shows earwigs can be beneficial in apple and pear trees, eating pests but doing minimal damage to the crop.
- They also feed on fungi and decaying plant material.
- They are food for other animals, including birds and lizards.
Tips to control earwigs in your garden:
- Remove their hiding places. Earwigs thrive in dark and moist areas during the day, coming out to feed at night.
- Clean up debris, leaf piles, and decaying plant matter
- Trap them by placing numerous traps throughout your yard.
- Use empty tuna or cat food cans with ½ inch of vegetable oil and a smelly substance such as fish oil or bacon grease. Place these in your garden bed with the top of the can level with the soil. In the morning, dispose of the trapped earwigs.
- Roll up damp newspaper, secure with rubber bands, and place in your garden bed. Next morning, collect them and shake the earwigs into a pail of soapy water.
- Baits such as SluggoPlus can be used, but often they are not effective if the earwigs have other attractive food sources like your tasty garden.
For more information about earwigs, please visit these links:
https://ipm.ucanr.edu/PMG/PESTNOTES/pn74102.html
Ode to an Earwig https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=51351
Earwigs in California (published 1975): https://essig.berkeley.edu/documents/cis/cis20.pdf
Washington State University study: https://www.mdpi.com/2075-4450/14/12/906
Help Desk of the UC Master Gardeners of Contra Costa County (SEH)
- Author: Help Desk Team
Are you a gardener with questions? Are you a beginning gardener just getting started? Do you want to know more about how to troubleshoot problems in your garden? Some of the topics addressed in our classes and material cover what, when, and how to plant, how to prepare the soil, and maintenance of your plants, including pruning.
The Contra Costa Master Gardener website (https://ccmg.ucanr.edu/) has links to information about both edible gardening and landscape gardening. We also offer a program called Vegetable Gardening for Beginners if you are interested in growing vegetables: https://ccmg.ucanr.edu/GrowingGardeners/
This is the handbook for this class: https://ucanr.edu/sites/ccmg/files/292083.pdf
There are many resources online through the University of California that can provide you with good information about specific pests and diseases, including the following:
• Home, garden, turf, and landscape pests: https://ipm.ucanr.edu/PMG/menu.homegarden.html
• UC California Garden Web: https://cagardenweb.ucanr.edu/
These are the books the Master Gardeners use for training and reference:
• The California Master Gardener Handbook: https://anrcatalog.ucanr.edu/Details.aspx?itemNo=3382
• Abiotic Disorders of Landscape Plants: https://anrcatalog.ucanr.edu/Items.aspx?search=abiotic%20disorders%20of%20landscape%20plants
• Pests of Landscape Trees and Shrubs: https://anrcatalog.ucanr.edu/Items.aspx?search=pests%20of%20landscape%20trees%20and%20shrubs
• Pests of Garden and Small Farm: https://anrcatalog.ucanr.edu/Items.aspx?search=pests%20of%20the%20garden%20and%20small%20farm
The UC Master Gardener volunteers of Contra Costa County are actively involved in bringing you educational programming. We partner with the Contra Costa County Library to present topics that will help you grow a healthy, thriving and sustainable garden. See the upcoming and past webinars here: https://ccmg.ucanr.edu/Webinars_and_Programming_/
You can find a schedule of in-person talks at libraries, at our Walnut Creek demonstration garden, and when Master Gardeners will have tables at Farmers Markets where you can ask questions at this link:
https://ccmg.ucanr.edu/Find_Us/Find_Us_by_Location/
You can also find past webinars as well as short, single-topic videos on a wide range of gardening topics on the Contra Costa Master Gardener Program YouTube channel: https://www.youtube.com/@CoCoMGUC
Still have questions? Send an email to the Contra Costa Master Gardener Program Help Desk: ccmg@ucanr.edu
• Include your name, phone number, and city.
• A description of the problem, including the name of the plant, when the problem began, and cultural history such as water, fertilizing, pruning, pesticides, etc.
• Photographs are very helpful. Include photos of the problem parts, but also photos of the whole plant.
Help Desk of the UC Master Gardeners of Contra Costa County (SEH)