- Author: Help Desk Team
It's getting close to the end of our summer gardening season. Now is the time to start thinking about next summer's garden. Do you have annual flower or vegetable varieties that did really well in your garden, and you'd like to grow them again next year?
Saving seeds to plant for a new crop is an ancient but simple and enjoyable process. In fact, it was routinely practiced until the 19th century when seed companies started to multiply. Seed saving is especially useful if the seeds for the item you want are hard to find. Additionally, it enables you to replant varieties that are well-suited to your garden's particular conditions.
Saving seeds from your own garden will start with seeds from the healthiest plants and produce that have the characteristics you want. You might choose the flowers that last the longest, or a vegetable plant that is most productive. You should also choose seeds from plants identified as “open pollinated” or “heirloom”. Seeds from hybrid varieties may not grow into plants even remotely like the variety you are growing.
Some plants such as tomatoes and most beans self-pollinate so their seeds will grow true to the variety. Others are pollinated by insects (e.g., squash and cucumbers) or wind (e.g., corn). If the original seeds are from open pollinated wind- and insect-pollinated plants, saved seeds may give unexpected results if there are other varieties of that vegetable or flower growing nearby. Flowers with easy-to-save seeds include calendulas, columbines, foxgloves, nasturtiums, poppies, sunflowers and zinnias.
Let seeds mature on the plant before collecting. This usually means leaving them longer than you would for good eating quality and letting some seed heads dry on the plant rather than deadheading. Determining when to harvest for seed saving is generally based on whether the seed is classified as wet or dry. Tomatoes, peppers, eggplants, and squash are examples of wet seeds. Wet seeds should be collected when the vegetable is slightly overripe. Beans and peas are dry seed plants. They should be harvested after the pods are fully mature and dry, and the beans or peas inside are hard.
After harvesting, there are three steps: cleaning, drying, and storing.
To clean wet seeds, separate them from the fleshy vegetable, rinse until they are clean, and spread them out to dry thoroughly. Dry them on a screen or a pan as the dried seed can be difficult to separate from paper towel or newspaper.
Some wet seeds, such as tomatoes, need another step before rinsing and drying. This mimics a natural process that lets beneficial microorganisms develop to remove a gelatinous coating on the seeds and destroy seed-borne diseases. Soak the seeds in their own juice (add about half as much water) for several days until a white mold appears. Swirl them daily. The viable seeds will sink to the bottom. Drain off the mold and anything floating, rinse the seeds well, and proceed with drying.
Cleaning dry seeds is easier. Dry seeds and pods are produced by beans, peas, lettuce, chives, most crucifers, and most flowers. After the pods or seed heads are fully dry, remove the seeds from their surrounding pods and membranes, also known as ‘chaff'. One method to remove the chaff is to rub the seeds against something mildly abrasive, such as a screen. Then, put the seeds in a jar; pour the seeds into another jar outside in the wind, or in front of a fan, and let the air carry the chaff away.
Make sure seeds are completely dry before storing. Store dried seeds in an airtight container in a cool place to avoid exposure to moisture and heat. Mark the container with the name of the plant, the date, and any notes on color, location, or size.
For more information on saving seeds, see these links:
• Beginners guide to seed saving: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=11597
• Seed saving basics: https://mgsantaclara.ucanr.edu/garden-help/how-to/seed-saving/
• Saving seeds of popular plants: https://mgsantaclara.ucanr.edu/garden-help/how-to/seed-saving/saving-seeds-of-popular-plants/
• Video: https://www.youtube.com/watch?v=edUwq0wMztM&t
• Book: What We Sow by Jennifer Jewell
Help Desk of the UC Master Gardeners of Contra Costa County (SEH)
- Author: Help Desk Team
Spider mites are very common pests found on many of our landscape and vegetable garden plants. They are tiny and difficult to see but once you learn about them, you might start seeing evidence of infestation on a wide variety of plants.
Spider mites live in colonies, mostly on the back side of leaves. They are less than 1/20 of an inch long, have eight legs, and if you look carefully, you can see two red eyespots. When their population is high, you might see dense webbing covering the leaves, twigs, or fruit.
Spider mites use piercing mouthparts to suck cell contents from leaves. Damage appears first as a stippling of light dots on the top of the leaves. Evidence of their presence can be seen or felt on some leaves—fecal matter, cast off exoskeletons of young mites, dead mites, and fine webbing becomes more obvious with heavy infestations. With heavier infestations, leaves can turn yellow and fall off.
Spider mite activity is most severe and damaging during hot, dusty conditions, and when plants are water-stressed. June through October are prime months for these little pests. In Contra Costa's relatively mild climate, spider mites can feed and reproduce year-round on evergreen plants. On deciduous plants, they can spend the winter under rough bark or on the ground.
To control spider mites, make sure your plants are not drought stressed. Dusty conditions often encourage spider mite outbreaks. Regular, forceful spraying of your plants with water, especially the undersides of the leaves, will often reduce their numbers and the damage they do.
Spider mites have many natural enemies that help control them, including lacewings, predatory thrips, and predatory mites. Maintaining a diverse garden habitat can encourage these predatory mites and insects to stay in your garden, waiting to assist with pest control.
If more control is needed, consider using an insecticidal soap or an insecticidal oil such as Neem oil in your sprayer and make sure you spray enough to fully cover both tops and bottoms of leaves. You'll need to spray soap again two or three days later to cover any newly hatched spider mites, because soap doesn't have residual action.
If you choose to spray insecticidal soap or insecticidal oil, don't spray if temperatures are over 90 degrees F and make sure to follow the label instructions. Before spraying it on the whole plant, test it on a few leaves to make sure it doesn't damage them. Using broad spectrum insecticides is not recommended as these can kill the natural enemies of spider mites, which may result in an increase in the spider mite population
How to prevent spider mites
Scout plants for their presence anytime hot and dry conditions occur. If you catch spider mites early, you may be able to prevent a large infestation just by removing a part of a plant or a single plant. Watering down dusty walkways and misting plants when it's hot and dry can make it less attractive to spider mites. If a plant becomes too infested and treatments are not working, consider removing that plant to reduce the chance of the spider mites traveling to other nearby plants.
For more information on managing spider mites, see this Pest Note: https://ipm.ucanr.edu/PMG/PESTNOTES/pn7405.html
Help Desk of the UC Master Gardeners of Contra Costa County (SEH)
- Author: Help Desk Team
This time of year, as the heat increases and things start to get dusty, you might see a number of webs on your plants. Uh oh. Are these webs a sign of spider mites?
Chances are the webs you see covering the ends of branches are actually created by spiders, a close relative to spider mites, and are nothing to worry about. Spiders are predators of insects, some of which are pests, and the webs are used for capturing prey. According to the UC Cooperative Extension, there are at least 54 families and over 1,000 species of spiders in California (https://ipm.ucanr.edu/natural-enemies/spiders/#gsc.tab=0).
Most spiders are beneficial to your garden. Think of them as a free pest control service and remember that among poisonous spiders only the widow spiders are commonly found in California, and these generally stay hidden in places like cellars or woodpiles. And even though the vast majority of spiders are harmless, that doesn't mean you want them surprising you in the garden! You can learn to recognize the many types of spiders hunting among your plants. Some of the more common web-spinning spiders you might see include:
• Dwarf Spiders: These tiny spiders hunt during the day and produce sheet-like or irregular crisscross webs on plant surfaces. You will find them in the plant canopy and in ground litter. They are common in fields and vegetable crops.
• Cobweb Spiders: Hang upside down in sticky, irregularly spun webs waiting for prey. Most are small and harmless, although widow spiders fall into this category.
• Funnel weavers include the Common House Spider: These spiders hang out in the garden, and on walls and ceilings in the house. They feed during the day and night, hiding and waiting for their prey near the ground in most types of vegetation. They spin funnel shaped webs, often with a flat extension covering the plant or soil. Their webs become conspicuous in morning light after collecting dew.
• Orb weavers or Garden Spiders: Often large and colorful, these spiders spin elaborate webs in concentric circles in the garden. They wait in their webs or nearby for prey to become entangled. Often, we can tell the species of the spider by the pattern woven into their web.
• Sac spiders: Typically nocturnal, Sac spiders live in silk tubes in places such as corners, beneath plants, or on bark, and stalk their prey at night. They occur both indoors and out.
Spiders that don't spin webs include the jumping spiders, lynx, crab and wolf spiders. Like their web-spinning cousins, these spiders are beneficial in your garden, preying on insects and other pests.
Are the webs damaging my plants?
In these photos you can see spider webs on a Daphne shrub, some succulents, and a Japanese Pieris. Notice there is no visible plant damage associated with the webs, although occasionally some dead leaves may get caught in a web, such as with the Japanese Pieris. A closer inspection shows the web hasn't caused the leaf damage — in this case it's sunburn from the recent heat wave.
Try to refrain from using insecticides as they aren't necessarily effective on the spiders, and you risk killing other beneficial insects. You can remove cobwebs from your plants by sweeping or hosing them away, or if inside, with a vacuum cleaner or mop. Instead, learn to recognize the spiders in your garden and you will come to appreciate the antics of the jumping spiders, or the beauty of a web with droplets of dew shining in the early morning.
• Quick Tips about spiders: https://ipm.ucanr.edu/QT/commongardenspiderscard.html
• Video to help you learn to identify spiders: https://www.youtube.com/watch?v=Bs-OUvY8L80.
• Identifying and managing spiders: https://ipm.ucanr.edu/PMG/PESTNOTES/pn7442.html
Help Desk of the UC Master Gardeners of Contra Costa County (RDH)
- 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)