Soil and Soil Analysis

Many soils and soilless mixes used by cannabis gardeners is peat based and mixed with other elements.

Many soils and soilless mixes used by cannabis gardeners is peat based and mixed with other elements. 

Soils are different, very different from one another. The average organic mineral soil is made up of 45% mineral particles, 5% living and dead organisms – bacteria, protozoa, microbes, fungi, earthworms, etc. – and 50% percent air and water. Three basic factors contribute to cannabis root’s ability to grow in a soil: texture, pH, and organic and mineral nutrient content. 

There are two basic ways most gardeners look at soil. The first is to see it as a living organic substance that must be nurtured so that cannabis roots can extract the necessary nutrients quickly efficiently and in maximum amounts. Soil outdoors and in large containers in greenhouses and indoors there are large volumes of soil and we can apply complete organic principles. The other way to look at soil is 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.

Dirt, Soil and Soilless Mix 

Dirt is found under your finger nails. Soil is mineral-based and best employed to grow cannabis in fields, planting beds, and very large containers. Soilless mixes are best to grow cannabis in small containers – indoors, outdoors and in greenhouses. The dynamics of small containers are not the same as in large containers, planting beds or Mother Earth. 

Rocky clayey soil is packed with nutrients, but the texture restricts air and moisture content. 

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. 

Heavy clay soil is easy to spot. It clumps up readily, is difficult to work and drains poorly. 

The texture, a tool used to express the mineral particle sizes and grains in sediment, are divided into three main groups, clay, loam and sand. Most soils are a mix of three basic soils particle sizes, sand, silt, and clay; all described below. 

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 0-14 pH scale denotes a tenfold increase or decrease. Nutrient uptake is best within a pH range of 6.0-6.5. Keeping the soil and water pH balanced and within the proper range is essential to a strong healthy cannabis crop. 

Soil varies from location to location on the earth and often varies from one place to another in your own backyard. 

Soil Analysis 

Soil tests are remarkably inexpensive (€20-200) and save medical cannabis gardeners much time and money wasted on fertilizers. Such tests also save the environment from excessive fertilizer pollution, including nitrates and phosphates, accumulation in the soil and runoff in the watershed. The excess fertilizer salts wash out into the water system where they cause countless environmental and health problems. For example, home gardeners use at least 10 times more fertilizer per square yard (m2) than big agribusiness farms. For every €10 spent of fertilizer by home gardeners, €9.00 is wasted! I recently spoke to an outdoor medical cannabis gardener who spends €3,000 on fertilizer annually. By applying the above information we see that 10 percent (€300) worth of fertilizer is actually used and 90 percent (€2,700) worth of fertilizer is washed into the soil and ground water. The gardener could easily save €2,700 by investing €20-200 in soil tests and following recommendations. 

Two basic types of soil analysis include BCSR and SLAN. 

BCSR (base cation saturation ratio) is commonly used by organic farmers and market gardeners in many countries. The results of this type of test provide the actual amount of nutrients in soil. The goal of BCSR testing is to achieve a balanced ratio of nutrients. The methodology uses Mehlich 3 extraction. The BCSR soil test method is supported by the National Sustainable Agriculture Information Service (ATTRA). 

Standard BCSR soil tests provide some of all of the following:
1.         Calcium
2.         Magnesium
3.         Potassium
4.         Sodium
5.         Phosphorus
6.         Sulfur
7.         Chlorine
8.         Minor elements
9.         Trace elements 

SLAN (sufficiency level of available nutrient) AKA Index (UK) system, is used by the majority of universities, farmers and big agribusiness 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. 

Standard SLAN soil tests provide some or all of all of the following and many include recommendations to improve soil nutrient content.

1.      pH
2.      ECe (dS/m)
3.      NO3-N (ppm)
4.      NH4-N (ppm)
5.      PO4-P (ppm)
6.      Potassium (ppm)
7.      Magnesium (ppm)
8.      Calcium (ppm)
9.      Sodium (ppm)
10.  SO4-S (ppm)
11.  Zinc (ppm)
12.  Manganese (ppm)
13.  Iron (ppm)
14.  Copper (ppm)
15.  Boron (ppm)

An optimum range for each reading and amendment and fertilizer recommendations are also included in many soil tests. For a little more money many labs include an easy-to-read graph. 

SLAN Soil Test Labs

Logan Labs, LLC: http://www.loganlabs.com* – Least expensive soil tests I have found – Basic test €20

A & L Western Laboratories, Inc. http://www.al-labs-west.com* – excellent service at a reasonable price

Spectrum Analytic, Inc. http://www.spectrumanalytic.com* this lab does everything and also shows a sample soil test 

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 their tests into 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 to not mention the target crop. 

Excellent sites to learn more about soil include:

http://soilandhealth.org, provides free e-books, mainly about holistic agriculture, holistic health and self-sufficient homestead living.

http://www.soilminerals.com, Complete information on garden soil minerals, nutrients, trace minerals, fertilizers and amendments for all gardens, farms, lawns, orchards and greenhouses.

www.google.com, search William A. Albrecht, Ph. D. He was the foremost authority on the relation of soil fertility to human health.

http://www.webpages.uidaho.edu/~bmahler/s44603.pdf, a short course in soil and plant diagnostics.

http://www.acresusa.com, Acres U.S.A. is North America's oldest, largest magazine covering commercial-scale organic and sustainable farming

www.attra.ncat.org, 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.marijuanagrowing.com, check our site including a forum for more updates and current discussion! 

*To find a soil test lab near you or in your country go to www.google.com and search for “soil analysis labs Europe” or “soil analysis labs (your country name)”