What Are Soil Amendments?
Soil amendments are tools of the seasoned gardener. They allow us to modify soil characteristics such as water-holding capacity, drainage, soil biology, and fertility in ways beneficial toplants. As a result, we can optimize soil conditions to suit specific groups of plants. For example, a vegetable garden will benefit from nutrient-rich composts. In contrast, a space dedicated to drought-tolerant plants will require fewer nutrients but an amendment that will produce soil with a loose structure and excellent drainage. Within a garden area, the localized use of various amendments allows plants with differing needs to be placed throughout the garden, providing greater diversity and interest. With the help of soil amendments, a diversity of plants will be healthy and thrive. Use amendments consistently and frequently.
Soil Amendments
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ClodBreaker - For Clay Soils
Soils with high clay content can pose problems for gardeners because they readilydevelop a structure that can result in compaction and poor drainage, adversely affecting plant growth. ClodBreaker is an excellent choice for improving the structural properties of clayey soils and adding some extra fertility. Using ClodBreaker should be the first step in clay soil management.
ClodBreaker has a long history. It is an American Soil & Stone product developed with Magic Gardens of Berkeley over 30 years ago. We formulated, mixed, and modified while they did the field testing and shared the results and recommendations. Eventually, we all agreed the product worked, and ClodBreaker was born. ClodBreaker, whose efficacy has been proven over the years, is an essential product in our arsenal of soil amendments.
How to use: ClodBreaker should be mixed as evenly as possible into the top 8 inches or more of soil. With clayey soil, it is best first to break up the ground to the 8-inch depth, ensuring no large clods remain. Reducing clumps to nothing larger than the size of a golf ball is best. Then spread a 4-inch layer of ClodBreaker over the soil and work it in as best as possible.
Where plant roots are close to the soil surface, ClodBreaker can be spread over the soil as a two-inch layer and gently raked into the first few inches of soil, careful not to injure any roots. This will help keep the soil surface open, so water and air can easily enter and move into the root zone. Some gardeners use ClodBreaker as a mulch spread about 2 inches deep. Then, in parts of the garden during a fall or early spring cleanup, the ClodBreaker can be raked into the upper layer of soil, adding fresh ClodBreaker. This way, there will be a slow buildup in the soil over the years, producing soil of good tilth.
$46.95 / yd
$31.75 / 1/2 yd
$7.95 / 2 cu ft bag
Walt Whitman Compost – An all-time favorite
The great American poet Walt Whitman was amazed and fascinated by the process of compost formation. He marveled at how the remains of dead plants and animals were turned into rich and fertile soil that brought forth new life. He appreciated the composting process as a purifying force of nature. It was a constant wonder to him. And so, we honor him by naming our favorite compost Walt Whitman.
Walt Whitman is our most popular soil amendment. It is a highly aged compost derived from plant materials. We blend it with some aged rice hulls to aid soil aeration and fortify the mixture with feather meal, an excellent organic nitrogen source. It works exceptionally well in improving soil structure and adding plant nutrients. In addition, it has abundant humates and complex organic compounds that stimulate plant growth. These substances are slow to break down and are essential for building soil organic matter while increasing the quantity of nutrients a soil can hold (known as cation exchange capacity, CEC).
How to use: Walt Whitman works best when incorporated evenlyinto the soil. First, spread a 3 to 4-inch layer over the soil's surface, then mix it as thoroughly as possible into the top 8 inches of soil. Some prefer to break up the ground to about an 8-inch depth first, then spread the compost over the soil and mix the two.
Walt Whitman is also used as a top dressing over the soil surrounding established plants, where digging would damage surface roots. It is best to spread the top dressing no thicker than 2 inches to keep excess nutrient salts from moving into the root zone at a level that will not harm the plant. This can be performed a couple of times during the growing season as long as there is a spacing of one month between applications.
$49.75 / yd
$33.60 / 1/2 yd
$6.25 / 3/4 cu ft bag
WonderGreen Compost – A good all-around amendment
WonderGreen is an excellent soil amendment derived from composting a diverse mix of plant materials. Because WonderGreen is from plants, it provides a balanced supply of plant nutrients back to plants when blended with soil, completing the nutrient cycle. In addition, the organic component of WonderGreen serves as an excellent food source for the web of soil organisms that are so important in maintaining the release of nutrients and the continued improvement of soil structure. WonderGreen is also rich in humates that stimulate plant growth and aid in forming a stable soil structure allowing improved air and water movement into the root zone of your plants. All of which can dramatically improve plant growth.
How to use: Walt Whitman works best when mixed thoroughly into the soil. First, spread a 3 to 4-inch layer over the soil's surface and incorporate it as evenly as possible into the upper 8 inches.Alternatively, break up the ground to about an 8-inch depth first, then spread the compost over the soil and mix.
WonderGreen is also used as a top dressing on the soil surface surrounding established plants, where digging would damage the shallow plant roots. It is best to spread the top dressing no thicker than 2 inches to keep excess nutrient salts from the compost from moving into the root zone at a level that will harm the plants. If you desire an additional nutrient boost, wait at least four weeks before adding the next top dressing. Top dressings are most effective when water moves through from the top. Drip lines placed below the compost are less effective.
$55.85 / yd
$37.70 / 1/2 yd
$8.95 / 2 cu ft bag
Worm Compost – Unique and Special
Worm Compost, also called Vermicompost or worm castings, is very special. If you have ever used it, you must have seen the positive effect on plant growth. Plants that have been growing poorly often perk up and show new life. Vegetables, roses, and plants of almost all types look better, flower more, and have a new vitality. Interestingly, it is not just the compost's nutrient content; additional factors are at play. The scientific literature is full of experiments that show that under the controlled condition where nutrient levels are held the same, plants in vermicompost still display more growth than those not receiving it. Many of the experiments also show better disease resistance of the plants, especially root diseases. What this extra factor is, is still being debated. One leading idea is that the critical factor lies in the microbiology of worm compost. As soil with its organic matter, insect exoskeletons, fungi, etc., passes through the worm’s gut, the digested material that comes out is much higher in beneficial bacteria and chemicals, such as complex humates, which are known to stimulate plant growth and suppress plant pathogens.
Not all worm composts are the same. The substrate, the food source, and how long the worms have lived in the substrate can vary considerably, and so does the quality of the compost. We have chosen to carry vermicompost where the substrate is sedge peat (already partially humified), the food is corn silage, and the worms are grown for bait. The final product has seen many generations of worms, meaning it is highly humified and has a very active microbiology, which is precisely what is required for top-quality vermicompost.
$65.25 / yd
$44.00 / 1/2 yd
$12.50 / 2 cu ft bag
Coconut Coir Pith – A renewable peat moss substitute
Coconut Coir Pith, often called Coco Peat, Coco Coir, or just Coir, is derived from the husks of coconuts. It is a byproduct of extracting and cleaning Coir, the fibers prevalent in a coconut husk. These are harvested to make many articles, such as door mats, rope, hanging plant baskets, etc. Although the correct name for this fiber is Coir, the word it has been coopted and used as a synonym for Coconut Coir Pith, a very different material.
Coconut Coir Pith is the soft pithy material surrounding the Coir (fibers). The "coir" used for growing plants is composed chiefly of rounded or irregularly shaped, soft-walled dead cells that can adsorb water much like a sponge. This material may have a small amount of fiber mixed in, but that is a minor component. This Coir Pith is soft, compressible, and readily adsorbs water while still holding a high percentage of air, making it an excellent choice as a container medium for growing plants.
About 20 years ago, when American Soil & Stone first began importing Coconut Coir Pith from Sri Lanka, the general opinion in the horticultural community was that it was inferior to Sphagnum Peat Moss, the dominant ingredient in potting mixes and organic soil amendments sold in plant nurseries. Yet the advantages of Coconut Coir Pith over Sphagnum peat are numerous. Whereas it takes thousands of years to replace the harvested Sphagnum moss, there is a new crop of coconuts every year. Whereas, when Sphagnum dries, it is difficult to rewet. The Coconut Coir Pith wets and dries and wets without any problem. Whereas Sphagnum shrinks away from the walls of a container when it dries, Coconut Coir Pith does not. Many a plant in Sphagnum has died after watering because the water flowed between the Sphagnum and the container wall and out the bottom instead of moving into the Sphagnum. This phenomenon created a substantial market for wetting agents that nurseries could sell you with each bag of potting mix or bale of peat moss.
Today, Coconut Coir Pith has gained dramatically in popularity because of the facts pointed out, plus the recognition that coir mixes make excellent media for growing all sorts of plants. It is also a perfect choice for starting seedlings and has a proven ability to stimulate root growth.
The above facts and a general recognition that "Coir" potting mixes make excellent media for growing all sorts of plants have dramatically increased its use and popularity. In addition, it is a perfect choice for starting seedlings and has a proven ability to stimulate root growth.
$125.00 / yd
$19.95 / 2 cu ft bag
About Our Soils
At American Soil & Stone, we take great pride in producing the highest quality soils. We have over 38 years of experience blending soil and 38 years of listening to our customers. This has given us the knowledge to provide some of the best soils and soil amendments that you will find in the Bay Area.
We produce a variety of soils and soil amendments, each formulated and optimized for a specific use. For example, American Soil & Stone makes a very nutrient-rich, open-structured soil for vegetable gardens, a moderately acidic, high organic matter soil for woodland-style gardens, and an open-structured, granular, fast-draining soil for cactus, succulents, and similar plants. The list goes on. We also produce custom-blended soils for projects with special requirements, such as rooftop gardens or unique plantings at botanical gardens. We have the knowledge and ability to handle almost any project.
Quality Control
We continuously run growth tests on all of our soils. Growth tests provide a much better indication of how soil performs than laboratory tests that only capture a single point in time. Soil is dynamic. As soon as you water or dig into it, its chemical, physical and biological properties begin to change. Using a growth test, we can follow the plant's response throughout its development and maturation. Growth tests also allow us to determine if the various components we blend into the soil are consistent with the high quality we require.
How We Mix Our Soil
Our soils are blends of many different materials, such as composts, organic fertilizers, mineral components, bark, soil, etc. The method by which all the components are blended is of extreme importance in determining how the soil will perform. A uniformly mixed soil is essential for consistent plant growth. To this end, American Soil & Stone has invested in the best mixing equipment to ensure that all ingredients are uniformly blended in the production of our soils and amendments. We use an electric batch mixer that is capable of evenly combining as little as one pound or less of an ingredient into a cubic yard of soil. The result is that our soils are consistently uniform within a batch and between batches. There are no fertilizer hot spots or dead spots to cause problems. Growth will be uniform and predictable. It is almost impossible to achieve this level of uniformity when using a front-end loader which is the common practice in our industry.