{"id":9108,"date":"2023-04-23T10:34:40","date_gmt":"2023-04-23T08:34:40","guid":{"rendered":"https:\/\/marijuanagrowing.com\/?p=9108"},"modified":"2024-01-31T13:37:15","modified_gmt":"2024-01-31T12:37:15","slug":"soil-chapter-18","status":"publish","type":"post","link":"https:\/\/marijuanagrowing.com\/soil-chapter-18\/","title":{"rendered":"Soil – Chapter 18"},"content":{"rendered":"\n

Soilsare different\u2014very different\u2014from one another. The average organic mineral soil is made up of 45 percent mineral particles; 5 percent living and dead organisms such as bacteria, protozoa, microbes, fungi, and earthworms; and 50 percent air and water. Three major factors contribute to cannabis roots\u2019 ability to grow in a soil: texture, pH, and nutrient content (organic and mineral).<\/p>\n\n\n\n

Most gardeners look at soil in two basic ways. The first is to see it as a living, organic substance that must be nurtured in order for cannabis roots to extract the necessary nutrients quickly, efficiently, and in maximum amounts. There are large volumes of soil in outdoor gardens and in large containers placed in green\u00adhouses or indoors, and for such volumes, we can apply complete organic principles. The second way to look at soil is as a growing medium that holds chemical elements, salt-based fertilizers (nutrients), air, and water. Indoors and often in greenhouses this is the way many gardeners approach growing.<\/p>\n\n\n\n

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Dirt, Soil, and Soilless Mix<\/strong>
Dirt is found under your fingernails. Soil is mineral-based and best employed to grow cannabis in fields, planting beds, and very large containers. Soilless mixes are best for growing cannabis in small containers\u2014indoors, outdoors and in greenhouses. The dynamics of small containers are not the same as in large containers, planting beds, or Mother Earth.<\/p>\n\n\n\n

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Many soils and soilless mixes used by cannabis gardeners are peat-based and are mixed with other elements.<\/em><\/p>\n\n\n\n

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Rocky, clayey soil is packed with nutrients, but its texture restricts air and moisture content.<\/em><\/p>\n\n\n\n

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Heavy clay soil is easy to spot. It clumps up readily, is difficult to work, and drains poorly.<\/em><\/p>\n\n\n\n

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Soil texture is governed by the size and physical makeup of the mineral particles. Proper soil texture is required for adequate root penetration, water and oxygen retention, and drainage as well as many other complex chemical processes.<\/p>\n\n\n\n

\u201cSoil texture\u201d is a descriptive tool used to express mineral particle sizes and grains in sediment, and is divided into three main groups, clay, loam, and sand. Most soils are a mix of three basic soil particle sizes: clay, silt, and sand (described below).<\/p>\n\n\n\n

Soil pH is a measure of the acid-to-alkaline balance. Soil life and mineral (nutrient) availability and uptake by roots are affected by soil pH levels. Every full-point change in the 0 to14 pH scale denotes a tenfold <\/em>increase or decrease. Nutrient uptake is best within a pH range of 6.0 to 6.5. Keeping the soil and water pH-balanced and within the proper range is essential to a strong, healthy cannabis crop.<\/p>\n\n\n\n

Soil varies from location to location on the earth and often varies from one place to another in your own backyard.<\/p>\n\n\n\n

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Soil Tests<\/h2>\n\n\n\n

Soil tests are remarkably inexpensive ($20\u2013$200 USD) and save medical cannabis gardeners much time and money wasted on fertilizers. Such tests also save the environment from ex\u00adcessive fertilizer pollution, including nitrates and phosphates, accumulation in the soil, and runoff in the watershed. Excess fertilizer salts wash out into the water system where they cause countless environmental and health problems. For example, home gardeners use at least ten times more fertilizer per square yard (m2) than big agribusiness farms. For every $10 USD spent on fertilizer by home gardeners, $9 USD is wasted! I recently spoke to an outdoor medical cannabis gardener who spends $3,000 USD on fertilizer annually. By applying the above information we see that 10 percent ($300 USD) worth of fertilizer is actually used and 90 percent ($2,700 USD worth of fertilizer) is washed into the soil and groundwater. The gardener could easily save $2,700 USD by invest\u00ading $20 to $200 USD in soil tests and the following recommendations.<\/p>\n\n\n\n

Familiarize yourself with 2 basic types of soil analysis: base cation saturation ratio (BCSR) and sufficiency level of available nutrients (SLAN).<\/p>\n\n\n\n

Base cation saturation ratio is commonly used by organic farmers and market gardeners in many countries. The results of BCSR testing provide the actual amounts of nutrients in soil. The goal of BCSR testing is to achieve a balanced ratio of nutrients. The methodology uses Mehlich 3 extraction with different testing parameters. The BCSR soil-test\u00ading method is supported by the National Sustainable Agriculture Information Service (ATTRA).<\/p>\n\n\n\n

Standard soil tests provide information for some or all of the following:
\u2022 calcium
\u2022 magnesium
\u2022 potassium
\u2022 sodium
\u2022 phosphorus
\u2022 sulfur
\u2022 chlorine
\u2022 minor elements
\u2022 trace elements<\/p>\n\n\n\n

Get a BCSR soil analysis ($110\u2013$150 USD) from Earthfort, http:\/\/earthfort.com\/lab services.html<\/a>.<\/p>\n\n\n\n

Also known as Index (UK) system, SLAN is used by the majority of uni\u00adversities, farmers, and big agribusinesses worldwide. The results of this type of test provide plant-available nutrient levels in a well-known range, ensuring neither a deficiency nor an excess. The methodology uses ammonium acetate extraction.<\/p>\n\n\n\n

Standard SLAN soil tests provide some or all of all of the following and many include recommendations to improve soil nutrient content.
\u2022 pH
\u2022 ECe (dS\/m)
\u2022 NO3-N (ppm)
\u2022 NH4-N (ppm)
\u2022 PO4-P (ppm)
\u2022 potassium (ppm)
\u2022 magnesium (ppm)
\u2022 calcium (ppm)
\u2022 sodium (ppm)
\u2022 SO4-S (ppm)
\u2022 zinc (ppm)
\u2022 manganese (ppm)
\u2022 iron (ppm)
\u2022 copper (ppm)
\u2022 boron (ppm)<\/p>\n\n\n\n

An optimum range for each reading and amendment and fertilizer recommen\u00addations are also included in many soil tests. For a little more money many labs include an easy-to-read graph.<\/p>\n\n\n\n

SLAN Soil Test Labs<\/strong><\/p>\n\n\n\n

Logan Labs, LLC: Least expensive soil tests I have found. Basic test $20 USD. www.loganlabs.com<\/a><\/p>\n\n\n\n

A&L Western Laboratories, Inc.: Excellent service at a reasonable price. https:\/\/al-labs-west.com\/<\/a><\/p>\n\n\n\n

Spectrum Analytic, Inc.: This lab does everything and also shows a sample soil test. www.spectrumanalytic.com<\/a><\/p>\n\n\n\n

Regardless of the type of test you choose, BCSR or SLAN, follow soil collection and submission guidelines to the letter. Gardeners living in a state or country that sanctions medicinal cannabis can send tests to local labs and request recommendations for cannabis. Medical gardeners who do not live in such a state can send their soil samples to any soil test lab but are advised not to mention the target crop.<\/p>\n\n\n\n

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Excellent sites to learn more about soil:<\/strong><\/p>\n\n\n\n

\u2022 Soil and Health Library provides free e-books, mainly about holistic agriculture, holistic health, and self-sufficient homestead living. https:\/\/soilandhealth.org<\/a><\/p>\n\n\n\n

\u2022 Soilminerals.com provides complete information on garden soil minerals, nutrients, trace minerals, fertilizers and amendments for all gardens, farms, lawns, orchards and greenhouses. www.soilminerals.com<\/a><\/p>\n\n\n\n

\u2022 University of Idaho, College of Agriculture offers a short course in soil and plant diagnostics. www.webpages.uidaho.edu\/~bmahler\/s44603.pdf<\/a><\/p>\n\n\n\n

\u2022 Acres USA is North America\u2019s oldest magazine covering commercial-scale organic and sustainable farming. www.acresusa.com<\/a><\/p>\n\n\n\n

\u2022 National Sustainable Agriculture Information Service (ATTRA) manages projects that promote self-reliance and sustainable lifestyles that include sustainable and renewable energy, energy conservation, resource-efficient housing, sustainable community development, and sustainable agriculture. www.attra.ncat.org<\/a><\/p>\n\n\n\n

\u2022 Jorge Cervantes Presents Marijuana Growing. Check our site, which includes a forum for updates and current discussion! www.marijuanagrowing.com<\/a><\/p>\n\n\n\n

\u2022 Google <\/strong>William A. Albrecht, PhD, a famous agronomist who pointed out the direct relationship between soil fertility and human health. www.google.com<\/a><\/p>\n\n\n\n

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Plant Tissue Analysis<\/h2>\n\n\n\n

Analyzing plant tissue for nutrient accumulation and utilization is common among professional farmers and green\u00adhouse growers. The tests cost less than $40 USD and help growers fine-tune fertilizer application. A small investment in periodic plant tissue analysis will lower fertilizer bills and increase yields, often substantially. Legal medicinal can\u00adnabis gardeners are also able to request plant tissue analysis from agricultural laboratories within states and countries that sanction medical cannabis.<\/p>\n\n\n\n

Soil tests measure nutrient levels that are potentially available for uptake by roots.<\/p>\n\n\n\n

The test is normally performed before planting, and it does not measure the actual concentration of nutrients inside of plants. For example, nitrogen is often deficient in plants even though it may be readily available in the soil. A tissue analysis, on the other hand, will provide current data to make timely decisions.<\/p>\n\n\n\n

Plant tissue analysis also helps ensure plants are not overfertilized. High concentrations of nitrogen, in particular, may affect human health because excess nitrates can convert to nitrites while being digested in the gut. Nitrates may react with other compounds to form nitrosamines that may be carcinogenic.<\/p>\n\n\n\n

Fine-tuning fertilization programs, including micronutrient levels, is much easier when accurate information from analysis of plant tissue is available. Micro\u00adnutrients are required in minute amounts, and an overdose could easily stunt a crop or significantly diminish yields.
Soil gardeners are able to test soil, which gives them an idea of which nutrients may be lacking. They can use subsequent plant tissue analysis to concentrate on determining amounts of specific elements and how those elements are utilized by plants.<\/p>\n\n\n\n

Hydroponic gardeners, who do not have soil tests at their disposal, find plant tissue analysis especially useful.<\/p>\n\n\n\n

Plant tissue analysis often takes 1 to 2 weeks when a specimen is sent to a laboratory. When crops are grown for 10 to 12 weeks total, this might be 10 percent of the plant\u2019s life. But, nitrogen tests* can be completed on the spot with a handheld meter in the garden, and results are available immediately.<\/p>\n\n\n\n

*A chlorophyll concentration meter measures chlorophyll content index (CCI) in foliage and the nitrogen content is extrapolated from this data. One molecule of chlorophyll contains four nitrogen atoms.<\/p>\n\n\n\n

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A soil test and the proper organic amendments before planting saved this gardener hundreds of dollars in fertilizer.<\/em><\/p>\n\n\n\n

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Texture and Types of Soil<\/h2>\n\n\n\n

To feel its texture, pick up a handful of moist outdoor soil and rub it between your fingers. Heavy clay soil will feel slick and greasy. Sandy soil feels grainy and rough. Silty soil will feel soft and spongy and be dark in color.<\/p>\n\n\n\n

Pick up a handful of moist potting soil and gently squeeze it to feel the texture. The soil should barely stay together and have a sponge effect when you slowly open your hand to release the pressure. Potting soils that do not fulfill these requirements should be thrown out or amended.<\/p>\n\n\n\n

The cation exchange capacity (CEC) of a growing medium is its capacity to hold cations that are available for uptake by the roots. The CEC is the number of cation charges held in 3.5 ounces (100 gm or 100 cc) of soil and is mea\u00adsured in milliequivalents (mEq) or cen\u00adtimoles\/kg on a scale from 0 to 100. A CEC of zero means the substrate holds no available cations for roots. A CEC of 100 means the medium always holds cations available for uptake by roots. Growing mediums that carry a negative electrical charge are the best.<\/p>\n\n\n\n

Cation exchange capacity is a calculated value that estimates the ability of a soil to attract, hold, and exchange cation elements; CEC values are reported in milliequivalents per 100 grams of soil (mEq\/100 gm). Soil-sample testing labo\u00adratories report a value for the CEC. Use the CEC numeric value on your report and then compare the number to the graph below to find your soil type.<\/p>\n\n\n\n

High-CEC soils hold more nutrients and water. But soils with high levels of clay (and high CEC readings) allow little room for oxygen and can slow root growth and nutrient uptake. If acidic, high-CEC soils also require more lime to buffer and lower pH.<\/p>\n\n\n\n

Nutrients take more time to leach out of high-CEC soils.<\/p>\n\n\n\n

Low-CEC soils hold nutrients poorly, which requires more frequent irrigation and lower volumes. These soils have a low capacity to retain cations. Add humus-based amendments to acidify and balance low-CEC soils.<\/p>\n\n\n\n

Nutrients must be dissolved in (water) solution in order to be absorbed by roots. When dissolved, they are in a form called \u201cions.\u201d This means that they have electrical charges. An electrical charge is either positive (+) or negative (-). For example, table salt, sodium chloride (NaCl), becomes 2 ions when dissolved: sodium (Na+) and chloride (Cl-). The sodium ion with a positive (+) charge is called a \u201ccation,\u201d and the chloride ion with a negative (-) charge is called an \u201canion.\u201d In chemistry, oppo\u00adsites attract and likes repel one another. In ionic form, nutrients are attracted to opposite charges\u2014positive attracts negative and vice versa.<\/p>\n\n\n\n

Soil chemistry can become very com\u00adplex, and it is beyond the scope of this book to dig deeply into the subject. For more information on the subject, check www.marijuanagrowing.com<\/a>.<\/p>\n\n\n\n

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This soilless mix is super dry but light and powdery. It holds a lot of water and air at the same time.<\/em><\/p>\n\n\n\n

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This handful of soil has everything necessary for strong plant growth.<\/em><\/p>\n\n\n\n

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This is very heavy clay soil. It is great for making pottery but horrible as garden soil.<\/em><\/p>\n\n\n\n

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Use this table to estimate the CEC of your soil:<\/p>\n\n\n\n

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SOIL<\/th>MIN.<\/th>MAX.<\/th><\/tr>
<\/td>CEC<\/td>CEC<\/td><\/tr>
sand<\/td>1<\/td>4<\/td><\/tr>
sandy loam<\/td>5<\/td>8<\/td><\/tr>
silt loam<\/td>8<\/td>20<\/td><\/tr>
clay loam<\/td>20<\/td>40<\/td><\/tr>
clay<\/td>40<\/td>80<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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