The best growing substrate for cannabis is what is best for your Cultivation Method, for Either indoor or outdoor Gardens.
The selection process for the soil and grow mediums best suited for cannabis cultivation should be methodical if you want the most ideal composition for a premium crop. The decisions you make before you plant seed, clones, or young stock are very important to the long-term success of your plants and must be appropriate to the type of farming practice you will use to cultivate your crop, and where you grow it.
"A good substrate is the key to strong root systems necessary for healthy, fast-growing cannabis plants that produce premium crops."
The method you use to cultivate your plants is the most significant factor in selection of the growing medium. To make the best choice, it is important to know there are two basic types of growing substrates in cannabis horticulture.
•Soil: Refers to field soil. (In the context of cannabis cultivation, “soil” is the material that occurs naturally, outdoors, although some products may have a label that includes “Potting Soil.” These are mixtures of materials that rarely contain any field soil.)
•Soilless: Manufactured mixtures of organic and inorganic materials. Use in containers and hydroponics.
Where your plants grow determines the formulations, or mixes, of the soils and amendments.
In the ground
Plant directly in amended planting holes or use planting bags containing potting soil designed for placement into the ground at varying depths.
Use prepared potting mixes, modifications of them or make your own.
Includes container and hydroponic growing techniques for closed rooms and greenhouses.
Choose from potting mixes designed for indoor use and fertilizers suited for indoor use like gravel and indoor soil mixed; clay pebble and indoor soil mixed; perlite and indoor soil mixed; stand-alone porous substrates like clay pebbles, gravel, or perlite; varied substrates listed mixed with coco, etc.
[Note: Do not bring soil from outside or opened bags to an interior growing space and only use products suited for indoor use when growing indoors, in a greenhouse or hydroponically. Closed soil products should remain sealed to avoid dehydration and pest contamination.]
Organic or Synthetic
In cannabis cultivation, you have the option of growing your plants organically (without artificial chemicals added) or by using products that contain synthetic formulations to enhance and control plant growth. While it is perfectly acceptable to use both organic and synthetic products together, if you plan to label your product as organically grown, you should not include non-organic substances, even in small amounts.
To make an informed decision about what method of cultivation you will utilize, consider your production goals, your budget, and your facilities. Ask for advice from friends, colleagues, local dispensaries, and sales people at your favorite suppliers. Try to identify trends in consumption that coincide with your own production standards and criteria. Think about how the chemicals you use on your plant affect it grows and later ingested by human consumption. As medical cannabis patients look for responsible and accurate labeling, many dispensaries test for impurities present in the plant material and reject any product that they deem unsuited for their patients, an important consideration if you plan to become a supplier.
Also, if not already a requirement in your location where medical or recreational cannabis is legally available, when contaminant testing becomes mandatory, products for sale must include a label with the testing results.
Whatever method you decide upon, organic, with synthetics or a combination of both, always read and follow the label instructions of the products you use; conserve whenever possible; recycle and more than anything else, realize you are a temporary steward of the land you work on and it requires your respect to receive any reward from it. Not New Age; just common sense.
Off the Shelf or Custom Mix
The marketplace offers a wide selection of premium soils and amendments from which to choose. Many growers use products especially suited for cannabis cultivation and readily available from plant nurseries, garden supply stores, and hydroponic garden stores. Others use products from a variety of sources and mix them for their own magical blend according to recipes they have developed, found on the internet or at cannabis events. Base your plan primarily on local availability since shipping soil and amendments can be costly because they are typically bulky and heavy.
Although retailers with old stock might disagree, there is a “healthy shelf life” to soils and most amendments so it is good to purchase only what you will need in a season or growing cycle. Volume buying to get a discount rarely pays off if you plan to store your materials for longer than 6 months, or from growing season to the next. Problems from decomposition and pest infestation are the chief reason for avoiding the storage of your soil products, not to mention the need to protect them from the elements, especially from water and wide temperature changes. Usually, your favorite local supplier can get what you want most times of the year, so there is no real need to “stock-up” on soil products, except for convenience.
5 Good Soil Products for Cannabis Cultivation*
Suited for use in containers, pots and raised beds
Happy Frog® Potting Soil
By Foxfarm Soil and Fertilizer Company
Fibrous content from aged forest products. Ingredients include earthworm castings, bat guano. Innoculated with soil microbes.
Available sizes: 12 Dry Quarts (0.46 cu. ft.), 2 cu ft bags
VermiSoil® Potting Soil
By VermiCrop Organics
Fibrous content from Sphagnum Peat Moss and low salt coco coir. Ingredients include worm castings, feather meal, blood meal, bone meal and bat guano. Fortified with kelp and inoculated with Mycorrhizae.
Available sizes: 1.5 cu oft bag, 4 cu ft tote, bulk
Fibrous content from 100% premium buffered coco coir, produced from renewable sources. Use right out of the bag and amend as required.
Available sizes: Brick (makes .32 cu ft), 1.75 cu ft bag, 5 kg bale (makes 2.2 cu ft when hydrated), Super sacks (55 cu ft or 2 cu yds).
By E.B. Stone
Contains aged forest products, coir, sphagnum peat moss, pumice, earthworm castings, feather meal, seabird guano, crab meal, fish bone meal, humic acid, gypsum, oystershell lime, dolomite lime, bat guano, kelp meal, yucca, mycorrhizal fungi and beneficial soil bacteria. Available size: 1.5 cu ft
Ancient Forest® (Amendment)
By General Organics (A division of General Hydroponics)
A natural product of 100% pure forest humus ideally suited for use as an amendment for soil or soilless substrates for improvement and as an inoculum with thousands of species of beneficial bacteria and fungi.
Available size: .5 cu ft
Design Your Own
Every growing situation is different, requiring modification and adaptation of the soil or growing medium to fit the needs of the plants in culture. What works for one grower might not be great for one in another part of the State; for example. Even within the same county, water, and microclimates will affect soil, or soilless mediums differently. Specific cannabis strains also have varied soil preferences.
In the pursuit of excellence, growers are always looking for ways to improve yield quantity and quality. The soil or soilless medium that performs best for your setup and strain selection may be what you create yourself. Water holding capacity in soil is vital for plant survival, so prioritize this aspect. Strive for good texture, correct pH, and nutrient content. Beyond those basic criteria, preferred soils can effectively remove impurities, eradicate disease agents, degrade contaminates and convert dead organic matter into nutrient forms needed for plant growth.
The ultimate grow medium for cannabis is what ultimately produces the best crop. Whether that comes from packaged merchandise, a modification of the ready-to-use products, or a completely unique mixture made from individual ingredients, great grow mediums come from great growers who understand the importance of nurturing their crops by working with their soil and keeping its habitat alive.
*Suggested for consideration, based on our actual use. Results may vary for each grower from use of these products; products, labeling, availability, and pricing subject to geographic distribution. Contact the manufacturer(s) or your local sources for these and other growing media for more information.
This blog post contains excerpts from “The Art of Growing Cannabis” with permission from the Author.