Of the many tools we use in the garden, one of the most effective multi-taskers is mulch. This water-saving,

soil-empowering material will amaze you with its miraculous qualities, making  your garden both beautiful and sustainable.

Mulch, a material loosely defined  as anything applied to the soil surface for protection and improvement, comes in two basic forms. Organic materials are carbon-based (i.e. used to be alive) and biodegradable. Nonorganic mulches are synthetics (e.g. plastic or rubber), or natural materials that decompose too slowly to benefit the soil in our lifetime (e.g. rocks). Organic mulches are generally considered to be the most beneficial for garden health, as they provide many services:

• Improved soil tilth: Tilth refers to how suitable the soil is for growing plants. Mulch provides both food and protection from Delta winds, the hot valley sun, and frosty winters for micro- and macro- organisms living in the soil. This stabilized environment allows them to go about their business, contributing nutrient availability, aeration, and soil structure.
• Erosion control: With better soil structure comes better water absorption. Mulch also slows heavy rains so water has a chance to percolate into the soil; in summer, mulched soils are less likely to form a crust, allowing for better percolation when irrigating.
• Weed control: Mulch prevents annual weeds from germinating by blocking sunlight from hitting the soil surface.
• Water conservation: Mulch helps retain soil moisture by reducing evaporation, which usually translates into reduced irrigation needs.
• Healthy roots: Fine roots are highly susceptible to drought stress and high temperatures; mulch helps keep the soil cool and hydrated, enhancing plant establishment and overall vigor. Healthy plants are more resistant to pest damage, requiring fewer chemicals and less maintenance.

The home gardener has many types of mulches to choose from; selecting the best for your situation depends on what and where it will be used, your budget, and availability. In beds where the ground will be worked every year (e.g. annual and vegetable beds), use short-lived materials such as straw or compost that can be incorporated into the soil if desired.

Long-lasting materials such as bark nuggets are best for perennial beds where a slow release of food over time is desired. Soil organisms use up nitrogen as they decompose the bark, so it should only be used on the surface to avoid nutrient deficiencies (nitrogen eventually returns to the soil as organisms die). 

Synthetic mulches such as black plastic are good where warming the soil is desired (e.g. for vegetable beds) or to eradicate soil-born pathogens. However, it is not the best choice for perennial beds in the home garden. Plastic restricts air flow and water penetration, creates a mess as it breaks down, is not completely biodegradable, and weeds can grow through holes and tears. Drip irrigation must be used underneath, which can be difficult to inspect and maintain when covered with plastic sheets.

Gravel has more aesthetic appeal than plastic and lasts a long time. Some plants, such as succulents, are much better off with gravel mulch. However, a huge disadvantage is it's high thermal mass, meaning it absorbs and radiates a lot of heat. This might be a bonus in some parts of the world, but not in a sweltering city like Stockton. Although some gravel is fine, avoid graveling your entire landscape to keep your air conditioning bills and the city's heat index down.

Correctly applying mulch is just as important as knowing what kind to use. For ornamental perennial beds, a  3” – 4” layer of coarse bark or 2” of small bark is recommended. Keep mulch 6” away from trunks to prevent root rot. Mulching techniques for vegetables and annuals varies greatly, depending on the crop and type of mulch being used. Newspaper, straw and grass clippings are common and readily available; make sure the last two are weed-free to avoid a bed full of undesirables!

More information on mulches can be found at the following websites:
www.ext.colostate.edu/mg/gardennotes/245.html#trees
ucanr.edu/sites/UrbanHort/files/80212.pdf

No talk of mulch would be complete without a discussion of where not to use it. Besides the obvious impracticality of mulching “the back 40”, approximately 70% of North American native bees are solitary ground-nesters. If you have a well-drained, sunny spot (preferably on a slope), leave it open for our native bees, whose habitat is rapidly disappearing. For best results, avoid cultivating or walking on this sacred ground. See the Xerces Society webpage for more information:
www.xerces.org/providing-nest-sites-for-pollinators

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.

Tomato picking season is here and I love to grow lots of them, although I have cut back from 100

plants to only 78. Unfortunately, where I live, thrips, any of an order of very small, destructive, usually small insects, carry a virus causing Tomato Spotted Wilt Virus and I lose several plants each year to this nasty disease. Having lots of plants is insurance that I will eat some tomatoes. There are a few resistant varieties to this disease, but they don't taste great.

A friend of mine liked to visit bars in Hawaii in search of the perfect Mai Tai. I have a similar quest searching for the best tasting, perfect tomato. Of course the search is nearly endless as named tomatoes are almost as numerous as named roses. Wikipedia says there are 7,500 varieties of tomato and the Seed Saver's Exchange Yearbook lists over 5,000 varieties. I grow a few new ones each year and it adds some excitement to the gardening experience to try new varieties. I also grow favorites every year that are good producers and good tasting.

Everyone seems to like Sun Gold, a yellow cherry tomato that is very sweet. It has been the top pick at our Master Gardener Tomato tasting for the past two or three years. The human sweet tooth is at work and cherry tomatoes, like Sun Gold and Sun Sugar are, well, sugary. When it comes to sweet tomatoes, Early Girl, a hybrid, is also high on my list and I think if I had only one tomato to grow this would be the one. It is an early bearer and keeps on producing all season, and the tomatoes are sweet and delicious. I once made tomato juice using only Early Girl and it was the sweetest, best tomato juice I ever tasted.

I am amazed how the tomato went from the New World after 1492 to Europe, Asia and then came back again with so many varieties. It is truly an international fruit. There are many with good taste and I am always willing to try those that score high in tomato tastings. The Cherokee Purple is noted for taste as is Brandywine, both winning many tomato tastings, but not noted for great yields.

For good productions and good tastes, the heirlooms Ace 55, Druzba, Crème Brule, Italian Heirloom, Soldacki, Paul Robeson, Thessaloniki, Bulgarian No. 7, Mortgage Lifter and Henderson's Winsell all fill the bill. For beautiful colorful tomatoes on the platter, I like bicolors such as Big Rainbow, Marizol Gold, Hillbilly, Gold Medal and Pineapple. Then there are the pure yellow and orange tomatoes: Persimmon, Golden Queen and Golden Jubilee and orange slicers, Amana Orange and Kellogg's Breakfast.

Tomatoes that don't perform well or taste good go off my list and don't get replanted. This year, I am giving Mamie Brown's Pink, Pink Berkeley Tie Dye, Dester, Verlon, Blue Berries, Trophy and Jaune Flamme a chance to make my favorites list. Because I have a greenhouse, heat mats and light stand, starting tomatoes is easier for me than for gardeners with only a warm windowsill. Hence, I started growing tomatoes and peppers for the Linden Garden Club's Annual Plant Sale about five or six years ago and it has been interesting to introduce new varieties to our clientele each year.

What to do with all those tomatoes? I take samples to our August Master Gardener's meeting for an

Master Gardener tomato tasting. LEE MILLER

annual tomato tasting. It is often disappointing, because I fail to cut back on the water as tomatoes ripen which enhances their flavor and sweetness. A more practical use is to can whole tomatoes or process them for sauce or tomato juice.

Tomatoes were once erroneously considered poisonous, but now are a health food. Tomatoes contain lycopene which gives them the red color. It is a powerful anti-oxidant that improves cell membranes and fends off free-radicals that can cause cancers. Tomatoes are a source of vitamins A and C and folic acid. Tomatoes contain a wide array of beneficial nutrients and antioxidants in addition to lycopene, including alpha-lipoic acid, choline, beta-carotene and lutein. For information on health benefits see: medicalnewstoday.com/articles/273031.php. Of course yellow tomatoes don't have lycopene, but have more of other nutrients, so take your pick of what is important; see: prevention.com/content/which-healthier-red-tomatoes-vs-yellow-tomatoes.

The tomato is really a fruit, but it is considered the most popularly grown vegetable in the United States, so if you are limited in garden space, take out some lawn and try a few tomatoes next year. Give them full sun, deep watering once or twice a week and enjoy for taste, health and the satisfaction of growing your own.

— If you have a gardening related question, you can contact the University of California Master Gardeners at (209) 953-6112. More information can be found at sjmastergardeners.ucanr.edu/

Humans love flowers for their aesthetic charm, but for pollinators, the need to feed is top priority. When out foraging, pollinators look for certain features indicating a plant's potential as a food source. Nectar and pollen quality are important; so too is the flower's shape, a determining factor for which species can access the goodies within.

Some plants appeal to a narrow range of pollinators while others are able to cast a broader net, aided by certain features:

• Tiny flowers clustered together reduces energy output by the pollinator when moving from one bloom to the next. Abundant, small blooms also increases the number of insects able to feed at once
• Extended anthers and stigma (a flower's reproductive parts) makes pollen access easier
• Flat-topped flower heads appeal to non-hovering pollinators, which need a “landing pad” while feeding (e.g. butterflies, many bee species)

In small gardens, selecting plant species that appeal to many will help support biodiversity, which is critical to the overall health of our ecosystem. Try some (or several!) of the following plants, all of which are hardy in the Central Valley:

Asteraceae family (Aster)
This is one of the largest plant families with approximately 23,000 species. Flowers in the aster family usually appear to have a single bloom on each stem; in actuality, each flower is a composite of tightly-packed individual tubular flowers. Some asters, such as dandelion and thistle, contain only tubular flowers. Others, such as daisies, also have ray flowers on the outside.

Planting a variety of asters can extend your bloom season from spring through fall, giving pollinators plenty of forage:

• Yarrow (Achillea millefolium) is native to California and a great plant for low-water gardens. It's evergreen foliage is frond-like and fragrant; graceful clusters of white flowers welcome myriad bees and butterflies to sip nectar from spring through summer. Good for full sun to part shade, growing to 1' high by 2' wide. Many cultivars and hybrids come in pink, magenta, or yellow-orange colors.

• Frikart's aster (Aster x frikartii ‘Monch') fills a difficult niche by blooming at a time of year when there is little forage in the garden. It puts on a display of lavender-colored blooms from summer into fall, which can be extended by deadheading. Provide some summer water and full sun. Grows to 1.5' tall by 1' wide.

• Blanket flower (Gaillardia x grandiflora) is one of my favorite low-water plants with its cheery, red and yellow blooms that last from late spring until frost. Plant in full sun, removing spent blooms to extend the season. It forms compact mounds about 1' high and wide. Blanket flower is an herbaceous perennial, and will die to the ground in winter. Watch for snails and slugs when they re-emerge in spring.

• Dusty miller (Senecio cineraria/Jacobaea maritima/Cineraria maritimus) has a long list of botanical aliases. Whatever you call it, Dusty miller makes a wonderful accent with it's silvery, fuzzy foliage and bright yellow flowers. An easy-care plant that is usually sold in nurseries like annuals (i.e. in 6-packs), they are evergreen and tough in our climate, requiring some water but having a decent amount of drought tolerance. Grows to 2' high and wide, blooming late spring through summer.

Eriogonum species (Buckwheat) 

Some of my favorite California natives are buckwheats; they are hardy, beautiful, and very attractive to native pollinators. Their tightly clustered flowers sit atop umbels rising 1 – 3 feet above the basal mound, depending on the species. Most species in cultivation are evergreen.

• St. Catherine's Lace (Eriogonum giganteum) is a real show-stopper, with it's silvery-green foliage and towering flower stalks to 3' tall. Atop each stalk sits a dinner plate-sized cluster of white flowers that attracts honeybees and butterflies; the flower heads age to rust as they dry, making a great accent for flower arrangements. This is a very large shrub, reaching up to 6' tall and wide when in bloom. Requires little water once established.

• Rosy buckwheat (Eriogonum grande var. rubescens) is at the opposite end of the size spectrum. This 1' tall, 1.5' wide perennial produces beautiful dark pink flower clusters in summer, attracting bees from many different families. Water 2-3 times a month once established. Likes morning sun and some afternoon shade.

More information on buckwheats can be found at:blogs.esanjoaquin.com/gardening/2014/09/12/buckwheats-for-central-valley-gardens/

Ceanothus species (California lilac) are some of California's most beloved natives, ranging in size from low-growing

ground covers to shrubby trees. Most Ceanothus for gardens are evergreen with dark green, glossy foliage. Flower clusters are typically shades of purplish – blue, though a few hybrids have white or light pink flowers. Provide good drainage, full sun to part shade, and little water once established, allowing soil to dry out slightly between waterings.

Visited by many bee and butterfly species, Ceanothus blooms in late March through late April, a valuable time slot and a way to extend your forage availability into the early part of the growing season. Many species, hybrids, and cultivars are available in nurseries; the following are recommended by the UC Davis Arboretum Teaching Nursery:

• Ceanothus ‘Concha' is a medium-large shrub to about 6 feet tall and wide with dark blue flowers.
• Ceanothus ‘Ray Hartman' is a large shrub to 20' tall and wide with sky blue flowers. Can be grown as a small tree.
• Ceanothus ‘Valley Violet' is a 4-foot shrub with long lasting violet-colored flowers

For more information on providing for pollinators, visit the Honey Bee Haven's website:
hhbhgarden.ucdavis.edu/welcome

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.

Chuck Ingels, Farm and Horticulture Advisor
UC Cooperative Extension, Sacramento County

Organic soil amendments are products that are mixed into soil for the overall purpose of benefitting plant growth and crop

production. Contrast that with mulch, which is placed on top of the soil surface to reduce soil moisture loss and water runoff, prevent weeds, and moderate soil temperatures.

Soil amendments improve coarse-textured (sandy) soils mainly by improving the water and nutrient holding capacity by the addition of organic matter. Fine-textured (clayey) soils are improved by creating larger soil pore spaces and improving soil aeration, which leads to better water infiltration and drainage.

Organic soil amendments contain plant nutrients, but most are not considered fertilizers because their nutrient content is often quite low, and because release of the nutrients to plant-available forms can take weeks, months, or longer depending on the product. The most important benefit of the organic matter additions is to provide an energy source for bacteria, fungi, and other microorganisms, as well as earthworms that live in the soil. These organisms create glues (polysaccharides) that hold soil particles together to create highly desirable soil aggregates. They also release plant-available nutrients as they die off.

From an environmental standpoint, using amendments from a local source can reduce fossil fuel use and air pollution compared to shipping products across the country. Consider producing compost at home, using well broken down local manure, or growing cover crops to add organic matter.

Soil Amendment Analyses (click on header to see amendment chart link)

In July 2012, UC Master Gardeners purchased nearly two dozen organic soil amendments, also known as soil conditioners, from several retail outlets in Sacramento County. Samples were bagged the next day and taken to Sunland Analytical Lab in Rancho Cordova, who provided a discount on our analyses in support of Harvest Day at the Fair Oaks Horticulture Center. A soil analysis panel was selected that included the following tests.

% N—percent total nitrogen. Products ranged from 0.7 to 2.1% N. There is no threshold for how much N should be in a product. More important is the C/N ratio.

C/N ratio—carbon-to-nitrogen ratio.  Ratios above about 30 (30% C to 1% N) result in nitrogen “tie-up” in the soil because soil microorganisms such as bacteria and fungi require both carbon and nitrogen in their diet. They feed on the carbon source (soil amendment) and extract nitrogen from the soil when the C/N ratio is over about 30.  This temporarily deprives plants of nitrogen until the microbes begin to die off which often takes about 2-3 weeks. With amendments below about 30, the amendment will readily begin to release its nitrogen to the soil. The lower the C/N ratio the faster the release.

pH—the measure of acidity or alkalinity of the amendment, with pH 7.0 being neutral. A pH of about 6.5 to 7.0 is ideal, but pH 5.0 to 8.0 may be acceptable depending on the pH of your soil. Low pH materials such as sphagnum peat moss are best for blueberries and some ornamentals such as azaleas and camellias, but there are questions about the sustainability of increased harvesting of peat bogs in Canada and the northern US.

% Organic Matter—the measure of carbon-based materials in the product. Ingredients other than organic matter may include soil, nutrients, and other inorganic particles. There is no threshold for % organic matter.

Conductivity—indicates the amount of salts present, also called electrical conductivity or EC. Many salts are essential for plant growth, but excess salts in soil may be detrimental to plant health, especially for seedlings, transplants, and salt-sensitive plants, and to soil microbes. The threshold of salts in amendments depends on many factors, especially the salinity of your soil and water. If you have soil or water with elevated salt content, use amendments with lower conductivity – about 3.0 or lower. In most of the Sacramento area, water is low in conductivity, so the threshold is higher – perhaps up to 10.0.

To see the Analyses of Selected Soil Amendments, go to:
ucanr.edu/sites/sacmg/Soil_Amendments/
If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.