By Michael-Anne Foley, Butte County Master Gardener, January 22 2016.
When is soil more than just dirt? When you want to grow healthy plants in your yard and garden, the soil is as important a factor as are water and sunlight. You can improve your soil's ability to support thriving plants of all kinds by protecting it from compaction, amending it with nutrients, and adding mulch as a top dressing. An ideal soil includes various proportions of clay, sand, humus, water and air. You can smell a good soil!
Why is Compacted Soil a Problem?
Compacted soil has less air and is less porous than well-aerated, friable soil. This means it is harder for roots in compacted soil to grow and harder for those roots to get air. Restricted roots are often unable to take up sufficient water or nutrients from the soil. These conditions inhibit plant growth, particularly during drought if soils are dry.
Compacted soil layers can either hold water in (by creating poor drainage), or keep water out (by preventing inadequate water infiltration and creating conditions that are too dry for plant growth and development).
A large number of organisms make up the “soil food web.” They range in size from tiny one-celled bacteria, algae, fungi, and protozoa, to nematodes, earthworms, insects and plants. These organisms are beneficial to plant health but also have difficulty living in compacted soil.
How to Prevent Soil Compaction
- Keep foot traffic limited to a few areas in the garden by using consistent pathways.
- Avoid walking on wet soil and in areas where you have recently loosened the soil.
- Working compost into soil can help alleviate soil compaction by improving soil structure, aeration, and water-holding capacity.
Amending the Soil
Soil amendments improve the physical properties of soils. They increase the water and nutrient-holding capacity of soil and improve aeration and water infiltration. Soil amendments are more than simply fertilizers. Fertilizers (especially synthetic chemicals) add nutrients to the soil for immediate use by plants, but little is retained in the soil. Soil amendments such as compost, humus, worm castings, and aged or composted animal manures improve the soil by making its texture and drainage more conducive to plant health. Soil amendments add nutrients to the microbes in soils, and the microbes then make those nutrients available to plants. The soils that help our foods and landscape plants grow are not sterile but are filled with microbes that are unseen by human eyes. These microbes make our soils healthy and productive.
Amendments are best chosen for the needs of the soil based on how the plants are performing. Landscape plants, annual flowers, and vegetables all have different needs. Commercial producers of amendments tailor blends to generalized garden uses. Some companies offer specific combinations of amendments for specific needs. Worm castings and homemade compost have been found to be among the best amendments because their ingredients are completely broken down and plants cannot be burned by concentrated synthetics.
Two useful websites to consult when determining appropriate amendments for your own yard are the “Analyses of Soil Amendments” at Analyses of Selected Soil Amendmentsand “Amendments for Landscape Soils” at Amendments for Landscape Soils
Using Mulch in the Garden
Mulch performs a number of important tasks in the landscape, and is particularly useful for the following purposes:
- Smothering weeds
- Retaining soil moisture
- Moderating soil temperature
- Feeding the soil by adding organic material as the mulch breaks down
- Alleviating soil compaction by absorbing pressure due to foot traffic
Types of Mulch
Mulch can be organic or inorganic. Each type has its uses in the landscape.
- Yard waste: grass clippings, leaves and small twigs can be used as mulch in moderation and may be best for use behind bushes or borders. Mulching with yard waste functions better when it is composted first. Because yard waste tends to look unsightly, a uniform mulch is often more attractive.
- Straw keeps weeds down and is good for vegetable gardens. It has a short life span.
- Pine bark and needles are good for weed control. Barks last longer, while needles allow water through.
- Wood chips: bark and wood pieces are attractive, provide good weed control and save water.
Inorganic mulch
- Landscape cloth of a woven material provides good weed control, allows air and water to pass through and, if used with organic mulch, can save time and labor for years to come.
- Black plastic can work well for annual plants like strawberries that can be planted through holes in the plastic mulch. Landscape plants, however, will not get enough air, water or nutrients.
- Rocks and gravel are relatively permanent but can be expensive. Decomposed granite tends to stay in place and look tidy.
- Spread a two-to-four-inch layer of organic biodegradable mulch over tree roots, shrubs and plant beds. Keep mulch two inches away from the woody trunks of trees and shrubs.
- Replenish annually or as needed to keep a two-to-four-inch layer. This depth is ideal for weed suppression and water conservation.
As you plan your 2016 garden, keep in mind the importance of keeping the soil aerated by preventing compaction, amending the soil, and mulching to conserve water and fight weeds.
By Barbara Ott, Butte County Master Gardener, January 8, 2016.
During the long days of summer sunlight, trees cast shade created by leaves that use sunlight to convert water and carbon dioxide into sugar. This is the process of photosynthesis, which feeds the tree and its leaves. Chlorophyll, responsible for the green color we see in leaves, is an important pigment that absorbs the light energy used in photosynthesis. As days grow shorter and temperatures begin to cool, trees respond by producing less chlorophyll, and photosynthesis slows and eventually comes to a stop. When that happens, pigments of yellow, orange and brown in the leaves (called carotenoids) begin to show through. Some trees produce pigments called anthocyanins in their leaves during the fall, creating red leaves.
A severe drought can delay the arrival of fall color by a few weeks. A dry fall with plenty of warm sunny days and cool nights contributes to vibrant late fall foliage.
Deciduous trees begin to release their leaves when cool temperatures trigger a hormone that sends a chemical message to the leaves to “let go.” Located where the leaf stem meets the branch is a thin bumpy line of microscopic cells called Abscission cells. These cells “cut” the leaf away from the stem when they receive that message. When the air moves them, these dangling leaves fall away. If the abscission cells do not develop, wind will not blow the leaves off. This is why some trees keep their brightly-colored fall foliage long after most other trees have dropped their leaves.
The yellow, orange and brown carotenoid colors in leaves remain fairly constant from year to year. Carotenoid is always present under the chlorophyll and does not change in response to weather. But when a series of warm autumn days and cool non-freezing nights occurs, it's a good year for red fall foliage. The warmth allows the leaves to produce sugar through photosynthesis, but the cool nights prevent the sap from flowing through the leaf into the branches and trunk.
Scientists offer several reasons for why some trees produce the anthocyanin that leads to bright reds. Primarily, it seems that anthocyanins protect leaves from excess sunlight and enable trees to recover remaining nutrients. This helps trees prepare for the next growing season. Anthocyanins give leaves their bright shades of red and purple. So, thanks to the warm days and cool nights we had this past fall, we enjoyed spectacular, vibrant leaf color all autumn long.
By Michael-Anne Foley, Butte County Master Gardener, December 25, 2015.
Winter is the time many gardeners reflect upon what worked in the garden over the past year, plan changes to implement in the coming months, and consider new plants to introduce. This January, why not begin planning a more wildlife-friendly garden? You can encourage birds, butterflies, lizards, frogs and a host of other beneficial native animals and insects to visit or reside in your garden by adding desirable habitat and plants to your home landscape.
By choosing to develop and maintain a garden that follows a few basic wildlife-friendly steps you can help contribute to a better local environment while reducing your water usage and maintenance costs, conserving local flora and fauna, and making our urban and rural areas more ecologically sustainable.
Why Attract Wildlife to the Garden?
It is enjoyable and satisfying to witness the activities of natural visitors in our gardens. Beneficial insects and animals also help to naturally control garden pests.
Creating a Wildlife-Friendly Garden
Provide food, shelter, and water, and avoid the use of toxic chemicals. Food required by beneficial wildlife includes pollen, nectar, and pest bugs. Shelter can be as simple as native bunch grasses that lady beetles use for winter shelter, while the bare ground next to the grasses can provide nesting sites for predatory ground-nesting wasps. A simple wide-rimmed shallow dish with a layer of sand on the bottom creates safe water access for many insects.
Hummingbird feeders filled with a solution of one part sugar to four parts water (brought to a boil and cooled) will give hummingbirds the energy to catch and eat the flying insects that constitute their main source of protein.
Selecting Wildlife-Friendly Plants
Our own native plants require less water, have fewer pests and attract beneficial insects that prey on the undesirable insects that feed on vegetables and fruiting plants.
- As a general rule, flowering plants that have a landing zone (the petals) for insects to settle on allows them to move by foot to the pollen and nectar. Cosmos, sunflowers, daisies, zinnias, salvias and echinacea are good examples.
- Planting in groups increases pollinator efficiency. If a pollinator can visit the same type of flower over and over, it doesn't have to relearn how to enter the flower and can transfer pollen to the same species, instead of squandering the pollen on unreceptive flowers.
- Plant with bloom season in mind, providing food from early spring to late fall. The goal is to provide pollen and nectar throughout the entire year.
- Herbs used in the kitchen support many species of pollinators. Chives, mint, marjoram, parsley, lavender, rosemary, dill, basil and fennel are all attractive to insects.
Providing Shelter
- While bird, bat, and owl boxes are familiar to most gardeners, shelters can also be constructed for native bees. There are many species of native bees that live all around us, but their nesting and rearing requirements can generally be broken into two categories: 1) those that nest above the ground in dead wood, hollow twigs, or crevices; and 2) those that nest in tunnels deep in the soil. About 30% of native bee species nest in wood or twigs and 70% nest in the soil. Soil nesters are more difficult to shelter: sometimes the best we can do is notice their small entrances and try to avoid compacting the soil above their tunnels.
Today, native insects face many challenges for survival through loss of habitat; use of pesticides and herbicides; diseases; predators; and disappearance of native flower populations. As gardeners in the Central Valley of California we can shape our environment in an ecologically sustainable way that celebrates our native wildlife.
By Eve Werner, Butte County Master Gardener, December 11, 2015.
Fall and winter are the perfect seasons to plant a native pollinator garden. Pollinators are the buzzing, flying creatures responsible for the formation of many of the fruits and vegetables that we humans love to eat. Planting for pollinators is a colorful way to attract interesting and beautiful birds, butterflies, bees, and insects to your garden while increasing the productivity of many edible plants.
Pollen is found in the flowers of plants. Different pollinators prefer variously shaped flowers to accommodate their personal anatomy. Selecting an assortment of California native plants with diverse flower shapes and staggered bloom times ensures that a wide variety of native pollinators will thrive in your garden.
Hummingbirds, for example, reach into tubular flowers with their long, thin beaks. Zauschneria californica (California Fuchsia; also known as Epilobium canum) is a perennial native to Butte County that is covered with brilliant orange-red tubular flowers from mid-summer through fall. This plant is a hummingbird magnet! Zauschneria ‘John Bixby' and Zauschneria ‘Calistoga' are especially attractive and well-behaved varieties of California Fuchsia. Plant Zauschneria in part- to full-sun areas of your garden. Water once or twice a month during the dry season. To keep it looking tidy, cut this perennial to within a couple inches of the ground annually in late fall/early winter.
To attract a miniature zoo over a long period, pair early-summer-blooming Salvia ‘Winnifred Gilman,' (Winnifred Gilman Sage), with late summer-blooming Eriogonum nudum, (Naked Buckwheat) or Erigonum fasciculatum (California Buckwheat). Plant these beauties in full sun. Water the sage once or twice a month. The buckwheats need no added summer water after the first year but can tolerant semi-weekly watering. Sit quietly and watch numerous species of tiny (non-stinging) native bees and wasps harvest nectar from the ball-like flower clusters of these plants. See if you can spot one-quarter-inch-long metallic green sweat bees among the crowd.
Mimulus (Diplacus) aurianticus (Sticky Monkey Flower) offers deep, wide tubular flowers that provide a helpful ‘landing pad' for several species of butterflies and bees. Hummingbirds love them, too. The soft orangey-yellow blossoms light up part shade gardens in the spring. Water Sticky Monkey Flower once or twice a month during the summer. It is stress deciduous, so it will lose its leaves or look wilted during the heat of summer.
Planting for pollinators is an easy and fun way to add a new dimension of interest to your native garden!
- Author: Brent McGhie
By Brent McGhie, Butte County Master Gardener, November 27, 2015.
Freezing temperatures damage plants by causing ice crystals to form in their cells. Frost-damaged vegetation withers and turns a dark brown or black. Ice crystals can also form in citrus fruit, causing juice vesicles inside the fruit to rupture and the fruit to dry out. Although frost-damaged fruit is edible after a freeze, it is susceptible to decay and often becomes unusable soon after the damage occurs.
Leaves, green wood and fruit are more frost sensitive than hard wood. Ripe fruit is more cold tolerant than green fruit because sugars in the juice act like antifreeze and lower the temperature at which it will freeze. Fruit is slightly less cold tolerant than leaves, and trees with fruit are less tolerant than trees without fruit, so in addition to preventing damaged fruit, picking fruit before a predicted freeze will not only save the fruit, but will help protect the entire tree as well.
Where a tree is planted can affect whether or not it is damaged by frost. Trees that are growing in open areas are more likely to suffer frost damage. Cold air tends to collect in low areas, so avoid these sites as well when planting citrus. On the other hand, trees can benefit from reflected and reradiated heat if they are planted near walls or other structures.
Certain cultural practices can also mitigate frost damage. Healthy, well-irrigated trees are better able to endure freezing temperatures. The full, leafy canopy of a healthy tree also helps shelter the fruit. In addition, moist soil retains heat better than dry soil and can actually warm the air near the soil surface. It is also a good idea to keep the ground around trees bare during the winter months. Bare, moist soil is better able to absorb and reradiate heat than soil insulated with mulch, weeds, or other ground covers. Fertilizing and pruning both encourage new growth, and delicate new growth is far more frost-sensitive than mature foliage. Thus, pruning and fertilizing of citrus trees should occur in the spring and early summer in order to give the new vegetation time to mature and harden off before cold weather sets in.
Frost-sensitive young trees can be protected by wrapping them with insulating material from the ground up to the main branches. In frost-prone areas, you might also consider covering trees that are one to three years old entirely, using a light material to trap heat being radiated by the ground. A frame or stakes should be used to minimize contact between the cover and leaves because ice may form where the cover touches any leaves. Sheets, burlap, or tarps are a better choice of cover material than plastic because plastic transfers more heat and if leaves come in contact with it they are more likely to freeze. The cover should extend as close to the ground as possible and be removed the next morning after the temperature rises.
If trees do show signs of frost damage, resist the urge to prune out “dead” wood in the early spring. Allow a few months for the trees to recover with the return of warm weather. Once new growth appears, the actual extent of the frost damage will be apparent and frost-killed branches can be removed without accidentally pruning out living material.
This article was based on information from the following sources:
http://homeorchard.ucdavis.edu/8100.pdf
http://ucanr.edu/sites/placernevadasmallfarms/files/135464.pdf