Is your garden soil as productive as you want? Need to make some enhancements?
Soil amendments may be the solution to improve the quality of your soil, but before making any additions or changes to your soil, it is best to understand what soil amendments are and how they could improve your soil. Remember, soil improvement will not overcome poor design, plant choice, incorrect planting, and lack of care.

What is Soil?

Soil development is the result of physical, chemical, and biological processes. The process of soil formation begins with wind, rain, and temperature fluctuations that break rocks down into fragments of various sizes. The particles that compose most soils in decreasing sizes are sand, silt, and clay. Therefore, the mixture of these three particles gives the soil its texture.
Soil high in sand tends to drain fast and is predisposed to drought, whereas soils high in clay store water, are heavy, and not permeable to air and water. Loam soils feel like they have an equal amount of sand, silt, and clay.
Soil formation results in layers like the layers of a cake. The topsoil is where the most organic matter resides and where most biological activity occurs. The subsoil layer tends to be brighter in color and finer textured than the topsoil, and the subsoil is prone to be low in organic matter and is generally less fitting for plant growth.

What makes soil productive?
Any soil, no matter how compact, can be improved by adding organic matter, becoming a nutrient-rich environment for any plant. Like humans, roots and soil organisms breathe and require sufficient air and water to thrive. As a result, good soil is not “solid,” instead, between 40 and 60 percent of the soil volume is pores. The pores may be infused with water or air, making both available to plants. The minor pores store water, and the largest pores control the aeration and circulation of water through the soil and are primarily the result of earthworm or root growth.
Fertile soils are a dynamic community of many genera of fungi, bacteria, insects, and mites that depends on organic matter as a fuel source. Without these organisms, minimal soil formation would take place. Therefore, these organisms, with earthworms and plants, provide the glue that holds the soil together and gives it structure. Consequently, rich soil provides physical support, water, air, and nutrients to plants and soil-dwelling organisms.

What is an amendment?
Amendment: Any matter added into the soil to enhance its physical attributes, such as water retention, permeability, drainage, aeration, and structure. They are indirectly affecting plant growth.
Mulch: Organic or inorganic materials added to the soil surface to help inhibit weed growth, conserve moisture, and add organic matter to the soil as they break down.

Soil conditioner: A type of amendment or material that improves soil structure, increases pore space, and enhances air exchange, water movement, and root growth.
Fertilizer: Directly affects plant growth by improving the supply of nutrients in the soil. Amendments may act as fertilizers by providing nutrients.
Organic material improves the soil structure and can be added to sandy soil to increase nutrient and moisture retention, help clay soils loosen, and provide better aeration and drainage. Compost is the most accessible organic material and can be purchased at garden supply stores. Examples of organic amendment include animal manure (Manure from farm animals such as cows, horses, sheep, goats, and chickens can be used, but never pig manure or pet waste, because of the risk of exposure to the parasites these may contain), compost, grass clipping, leaf mold, straw, wood chips, wood ash, and worm casting.
Inorganic amendments are either mined or artificial; they may improve soil texture and structure and aid in pH adjustment. Examples of inorganic amendments include greensand, gypsum, lime, perlite, pumice, and sand.
Topsoil may be added to raise the soil level to a minimum depth of 6 to 8 inches. If you add topsoil, it should be mixed into the existing soil. Do not just lay it on top of the old soil; this may create a layered profile, making it difficult for water to move through or for plant roots to penetrate.

Soil pH
The ideal soil pH ranges from 5.5 – 7.0. Soils with a pH of 5.5 or lower are too acidic. Lime can be applied to raise the soil ph. Soils with a pH of 7.0 or higher are too alkaline and can be modified with elemental sulfur. A soil analysis may help determine what kind of amendment may be needed.
In conclusion, knowing what type of soil your garden has will help determine what kind of amendment may be needed.

For more information:

http://ipm.ucanr.edu/TOOLS/TURF/SITEPREP/soilamen.html

https://marinmg.ucanr.edu/BASICS/COMPOST_-_OTHER_SOIL_AMENDMENTS/

https://www.uvm.edu/sites/default/files/Extension-Master-Gardener/improvinggardensoilswithcomposting.pdf

https://extension.oregonstate.edu/news/add-organic-matter-improve-garden-soils

https://www.lotusland.org/greengarden/building-sustainable-gardens/

https://www.thespruce.com/compost-black-gold-for-your-garden-soil-1403130

 

When we lived in St. Louis Missouri, pin oaks graced the yards of our neighborhoods. When they dropped their leaves in the fall, the raking began with families filling up paper sacks purchased in bulk from the box stores. The annual fall event was as important as Halloween. The more rows of sacks on the curb, the more efficient and conscientious you were about raking leaves. I was so thankful burning was not allowed.

However, I never filled any paper sacks ever. I thought it a waste of time and energy. Instead, I first waited for the leaves in my yard to be windblown around the neighborhood. “Who can control the wind?” I thought. What a great idea this was. Some of my neighbors must have had the same idea and their leaves would end up equally in my yard. After seeing all of the leaves had fallen and been blown or raked, I would run my lawnmower with a mulching blade, cutting the grass and disintegrating the leaves. With the first fall rains, the leaves disappeared and my lawn and oak trees looked great in the spring.

We encountered a much different situation when we moved back to California in 2016. We now have a fenced, partially xeriscape backyard, with islands of mature valley oaks surrounded by a sea of river rocks. There was
an adjacent lawn area separated by a sidewalk where the late fall and winter oak leaves could be blown or raked for mowing or collection. However, there were too many leaves and not enough lawn to absorb the mutinous gathering. Where was my “aha” moment now?

Collaborating with Master Gardeners and reviewing university studies on leaf mulching / compositing, my first “aha” moment arrived. The answers to whether you should mulch oak leaves into turf, compost the leaves, use leaves for landscape mulch, till leaves into your vegetable garden, simply let the leaf litter lie, or combinations thereof, were summed up in two words: “it depends.” For my situation, it made sense to mulch some leaves into the turf, collect some for landscape mulch, till some into the vegetable garden, and compost the remainder. I was happy to have choices.
Mother Nature has been recycling oak leaves back into soil nutrients for plant growth since the first oak tree. There are numerous University studies that help us to better understand this process. Soil organisms (bacteria, fungi, worms, and insects) utilize oak leaves as a food source and in particular, release nitrogen, phosphorous, and sulfur back into the soil. By design, the rate of leaf litter decomposition and release of nutrients back into the soil is relatively slow. This is partially due to the low nitrogen content of leaves which controls the rate of decomposition. If you are using shredded leaves for landscape mulch, this is a good thing, as you want mulch to remain in place to prevent weeds from germinating / growing, hold in moisture, and slowly release nutrients back into the soil. However, if you are mulching leaves into turf, tilling into the vegetable garden soil or composting, an accelerated rate of decomposition may be more desirable.

What factors influence plant material decomposition rate? A critical factor is the amount of nitrogen in the plant material. Similar to when you fertilize your lawn with nitrogen and the grass grows faster, decomposers will also multiply and grow more quickly with more nitrogen. Decomposers break down decaying plant material for energy and cellular growth. The carbon to nitrogen ratio (C:N) largely determines leaf decomposition rates. Oak leaves are high in carbon and relatively low in nitrogen with a C:N ratio of around 60:1.

To increase decomposition rates, decomposers require more nitrogen, around 30:1, which translates into one pound of nitrogen to thirty pounds of lightly moist organic material. The 30:1 ratio is achieved by blending oak leaves with high nitrogen sources such as inorganic fertilizer, grass clippings, and manures. Additional environmental factors that will speed up decomposition rates include adequate aeration, moisture, particle size, and heat. The Soil and Fertilizer Management Chapter of the California Master Gardener Handbook, Second Edition, as well as The University of Missouri Extension “Making and Using Compost” provides information on how to optimize decomposition rates, C:N ratios of compostable organic and inorganic materials, how to set up a compost pile and trouble shooting.

Michigan State and Missouri Universities have studied mulching leaves into turf which skips the bagging, reduces fertilizer use, and reduces lawn weeds. Leaf particle size is a key variable as the leaf particles need to be small enough to fall between the blades of grass and not form layers / smother the lawn. At times, there may be too many leaves to mulch adequately and with a bagging mower, it is possible to alternate mulching leaves into turf with collecting the ground leaves for landscape mulch or composting. Michigan State University has a video illustrating mulching leaves back into turf.

When tilling oak leaf litter (low in nitrogen) into soil as an amendment, the decomposer population and activities increase. However, Instead of adding nitrogen to the soil, they incorporate the nitrogen into their own cellular tissues. In this process called “Immobilization”, microbes are competing with plants for nitrogen. Therefore, if incorporating leaf litter into the soil at time of planting, it is recommended to add inorganic nitrogen fertilizer to balance the C:N ratio to around 30:1. Immobilization only temporarily locks up nitrogen and when the microorganisms die after consuming their food source, the nitrogen contained in their cells is converted back to plant available nitrogen.

For More Information

ANRCatalog - California Master Gardener Handbook--2nd Ed - ANR Catalog (ucanr.edu)
Making and Using Compost, G6956 | MU Extension (missouri.edu)
Don't Bag It - Leaf Management Plan - Earth-Kind® Landscaping Earth-Kind® Landscaping (tamu.edu)
Mulch leaves into turf for a smart lawn - Gardening in Michigan (msu.edu)
Don't sweep your leaves to the curb! Mulch them back into your lawn or garden - MSU Extension
https://www.youtube.com/watch?v=os-EFAPLcP0
Recycling Autumn Leaves // Missouri Environment and Garden News Article // Integrated Pest Management, University of Missouri
Autumn Leaves: From Trash to Treasure // Missouri Environment and Garden News Article // Integrated Pest Management, University of Missouri
Autumn Leaves - Myth and Reality | Missouri Department of Conservation (mo.gov)

 

 

 

During the summer, the MG Herb Study group met monthly to discover and discuss the herb of the month. June's herb was Basil, July's was mint, and August's was lemon balm. All three are great additions for gardens and add unique flavors and aromas to chosen dishes.

September's herb is coffee. In Europe and England, cooks add ground coffee or liquid coffee to foods to enhance flavors and highlight other herbs. It is more than just a wake-up beverage. October's herb is caraway. 

Another herb worth mentioning here is the weed Common Purslane. This is an edible plant which can substitute for spinach or lettuce; raw in salads or sandwiches or cooked in soups or quiche. Purslane grows in parts of the world with a wide range of environments including gardens, sidewalk cracks, rocky gravel beds, and even harsh desert-like caliche soil. It tolerates extremes including drought and very salty or nutrient-deficient soil.

Purslane has a long history of use in traditional/alternative medicine and is very nutritional. A 100-gram (3.5 oz) portion contains):

• Vitamin A (from beta-carotene): 26% of the DV.
• Vitamin C: 35% of the DV.
• Magnesium: 17% of the DV.
• Manganese: 15% of the DV.
• Potassium: 14% of the DV.
• Iron: 11% of the DV.
• Calcium: 7% of the RDI.
• It also contains lesser amounts of vitamins B1, B2, B3, folate, copper, and phosphorus.

You get all these nutrients in only sixteen calories! This makes it one of the most nutrient-dense foods on the planet, calorie for calorie!

Allium is a genus of monocotyledonous flowering plants that includes hundreds of species, including the cultivated onion, garlic, scallion, shallot, leek, and chives. Allium is Latin for garlic. Allium is an herb.

Alum is not an herb! An alum is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula XAl(SO?)?·12 H?O, with “X” being a cation such as potassium or ammonium. Aluminium and Aluminum are the same element!

For more information on the herb of the month, check out the Herb Society of America. 

Avid gardeners know a successful garden is a result of research, planning, trial and error, hard work, and evolution. The Learning Landscape located at the Robert J. Cabral Agricultural Center, 2101 E. Earhart Avenue, in Stockton, is an example of these principles as a work-in-progress and now maturing garden. From its inception and design, it has, through the hard work of the San Joaquin Master Gardeners (SJMG) and its program leaders, evolved from its original generic commercial landscape plan into a Learning Landscape. 

When the Robert J. Cabral Agricultural Center opened in August 2008, the southwestern corner of the landscape had been set aside for the Learning Landscape through the efforts of then-San Joaquin UCCE County Director, Mick Canevari (emeritus).

Professional landscape designers prepared plans for the Learning Landscape without consulting the SJMG's program coordinator Marcy Sousa, or the UC Horticultural Advisor Ashley Bassinger. Sousa and Bassinger were able to review and rework some of the plans via change orders before the garden's installation. They swapped out redwood trees for more climate-appropriate selections, changed paths to permeable concrete, and add crushed granite areas, in accordance with best water runoff mitigation principles and garden practices for our Mediterranean climate. It was too late in the process to swap out many of the plantings and it has taken years to replace large swaths of plantings and form it into its current state (for example, a large rosemary patch is now the Mediterranean fruit tree area). 

Concurrent with the installation of the original garden, the first group of SJMGs were graduating from the resurrected local program. Sousa polled the MGs who expressed interest in volunteering in the garden to initially ascertain the interests of the graduates. Sousa and Bassinger also researched and toured demonstration gardens in Sacramento, Fresno, Orange County and Los Angeles. The tour provided practical insight into working gardens maintained by volunteers. The duo then extracted ideas suitable for the San Joaquin plot. 

Based on the survey results and research trips, Sousa and Bassinger began adding appropriate plantings. They incorporated native, pollinator, and Mediterranean plants and trees into the landscape, and carved out an area for the Arboretum All Stars. 

The gardens have not been without challenges. Manzanitas and other plantings have been lost due to irrigation issues. The All Stars section sunk lower than the surrounding gardens and had to be dug out and rebuilt. Construction debris had 

In 2010, Karrie Reid (just retired), took over as UCCE Environmental Horticultural Advisor and brought vast local expertise and structure to the gardens. Reid held meetings to brainstorm how to make the gardens more in line with MG goals. The group formalized seven themed sections; an 8th section was designated in 2021. Throughout the redesign of the gardens, Reid insisted on plantings that were truly appropriate for each themed area, suitable for the region, and with the exception of edible plants, either low or moderate water-use according to the Water Use Classification of Landscape Species.

The themed gardens are: 

• Entry Garden 
• Foliage Garden 
• Arboretum All Stars 
• Edibles Garden 
• Pollinator Garden 
• Mediterranean Garden 
• California Natives 
• Cutting Flowers Garden (designated in 2021)

Several MGs were instrumental in the creation of the newly formed theme gardens. The Foliage Garden was the brainchild of MGs Susan Price and Sharon McDonnell, and has remained under McDonnell's supervision since its inception. MGs Kathy Grant and Rosalee Osman proposed and created the Pollinator Garden.

Volunteers then began the heavy lifting of turning the generic landscape into the themed gardens. Excepting one Xylosma tree, all plants and trees were removed from the Foliage and Pollinator gardens and replanted with appropriate species. Decomposed granite pathways were added into those gardens to allow visitors access to the plantings, and to avoid soil compaction and trampling of plants.

Edible landscaping was an emerging theme at the time. MG Rich Mullenbach was instrumental in removing excessive plantings, including a thorny Hawthorne tree that was a maintenance issue. He regraded the area in the Edible Landscape that became a pathway, and built the retaining walls, and volunteered many hours in the gardens.

MG Steve Sanguinetti has and continues to provide his expertise in reworking, repairing, and maintaining the irrigation system. Reid converted the irrigation in the Mediterranean Garden and Reid and Sanguinetti used the conversion of irrigation in the California Native section as an educational demonstration for MGs and the public at an Open Garden Day. Over time, Sanguinetti and Reid converted irrigation in much of the garden from point-source to modern internal drip line.

Reid also brought management structure to the gardens. She created Team Leader positions for each garden section. Team Leaders are responsible for the planning, communication, recruiting volunteers, organizing workdays, monitoring irrigation, and overall maintenance of the plants and trees within their gardens. The Team Leaders are entrusted with researching species appropriate for their garden and working with their group of volunteers to maintain each area. Several areas—the pollinator, cutting flowers, and edibles gardens change often and are reflective of the team's styles and preferences.  

In addition to creating a management structure for the gardens, Reid created maps and maintenance calendars for each section and worked with the County to create signage for the overall garden and individual garden sections.

Reid's contributions and direction of the gardens for the past 12 years has been enormous. When interviewed, she mentioned,“Developing the gardens has been an ever-evolving project only accomplished through the endless hours given by MGs to this endeavor. I am incredibly proud of all their hard work, because it has created an inspirational space used frequently by the building's employees, as well as visitors to the Ag Center on business, who stroll through, take a break, or have their lunch. Additionally, it has become a resource for local landscape professionals and home gardeners who use it for ideas for regionally appropriate gardens. The signage we developed means the gardens are educational, even when we aren't on site to teach. I recently had the long-time head of marketing for Green Acres Nurseries tell me he sends clients here all the time to see our garden because of the many examples of sustainable and inspirational plant selections. It is so rewarding to see the goals we set come to life and I know it will remain a vital asset to the region.”

Master Gardeners are educated by subject matter experts in a variety of fields, including pest management, composting, plant pathology and propagation, water usage, and other subjects based upon their geographic location. They are tasked with educating the public based upon research-based practices. The Learning Landscape is a tool for MGs to learn and utilize best practices for gardening, and is one vehicle used for educating the public.

The San Joaquin County Master Gardener's program is funded and supported by AB939 and through San Joaquin County Solid Waste Division.