GUEST COLUMN BY DR. BRIAN E. JACKSON SOILLESS SUBSTRATE SELECTION: Find the RIGHT PRODUCT and PARTNER Choosing a here are many decisions that a grower must instead of mineral (field) soil for a variety of reasons that knowledgeable, make in relation to the production of plants have been well established and proven during the past grown in any type of container system. Con- six decades. These soilless materials give growers two of reliable supplier siderations such as site location, outdoor or the most powerful tools in managing plant growth and is just as indoor production, genetics of plant material, yield: precision and control. The selection of the optimal important as organic or synthetic fertilizers, pesticide/fungi- substrate should be considered carefully. cide or herbicide selection, container type and picking the right size, irrigation method, and more all have to be CHOOSING SUPPLIERS Testablished early in the process. The most fundamental pieces of advice I could give substrate for your operation. Also near the top of that list of critical decisions is someone in the market to purchase soilless substrates substrate selection, as it can weigh heavily in how you are to 1) pick a supplier, not a product and 2) do not let Here are key resolve many of the above considerations. cost be the primary/initial deciding factor in substrate questions to ask The basic functions of any container substrate selection. This is true for growers purchasing raw when deciding are the same as the functions mineral soil serves for substrate materials with plans to blend their own outdoor-grown plants: stability, water supply, nutrient substrates at their growing operations as well as for on both. reservoir and availability, and adequate air (oxygen) for growers purchasing pre-blended, ready-to-use mixes. proper root growth and development. Soilless sub- There is a lot to unpack in those two statements, so let strates, organic or inorganic and single component or me offer some justification to my recommendations. multiple component mixes (Fig. 1) are used in containers One of the most valuable attributes of a commercial | ADOBE STOCK PIXEL-SHOT 58 | CANNABIS BUSINESS TIMES | OCTOBER 2020 substrate supplier is the technical and keep them in storage for many its resources has been a priority for assistance experts from those com- months in case a problem is ever dis- many companies and consumers. panies who help their customers covered. If so, they have a reference In a global effort to reduce the envi- QUESTIONS make decisions and guide them with product quality data. ronmental impact of growing plants, through production problems. The Research and innovation devel- horticultural growing practices are GROWERS assurance that comes with having opment within companies (depend- taking significant steps forward in someone to call in times of need is ing on size) can be another point of sustainability, and the substrate MIGHT ASK often worth paying a little bit more attraction. Is the company planning industry has been a leader in this for certain products. Growers who for the future? Are they offering new effort, as overall, it has focused on make their own substrates or who products based on research of their utilizing more localized/regional SUPPLIERS buy from suppliers who offer no own? Are they collaborating or coop- growing media components to re- technical support may be left to erating with university researchers or duce freight distances, implementing INCLUDE: figure out problems on their own or other industry partners if they do not more advanced peat harvesting and • What steps do you forced to bring in paid consultants have a researcher (or team) of their peat bog restoration practices, and implement to ensure to help solve their problems. own? Not all substrate suppliers are developing more organic growing product quality? Another key attribute worth in- large enough to maintain large or media products to substitute inor- • Will your product quiring about is the Quality Control active research programs, but that ganic or non-renewable materials. be the same from (QC) program that the company should not disqualify them as a po- If sustainability is a priority shipment to ship- has. Engineered substrates are tential supplier. However, all suppliers for growers, it’s important to ask ment or season to thoroughly designed materials that should stay updated on current potential suppliers about their season? have been through many years research, industry trends, and new sustainability efforts. There are • For new product of research and development to products and growing systems, as numerous certifications that sub- offerings, has there get to commercialization. Com- all of these are evolving quickly. As strate producers can participate in been thorough panies should have strict oper- a grower, you should be able to de- to verify their efforts to protect the testing of product ating guidelines on raw material termine if a company is up to speed environment (e.g., Veriflora certifi- performance and acquisition and handling, material on the latest industry innovations cation, Global Reporting Initiative plant/crop success? processing, material blending, and developments by comparing (GRI), International Organization • Are you able to bagging, and shipping. These steps feedback with that of other suppliers for Standardization (ISO), among help me calculate ensure consistency across batches you talk to by asking the supplier to others). Ask about their efforts in how much and and over time. Suppliers should be address how they are staying current resource conservation, ecosystem which type growing regularly checking various material and innovative, or by asking other protection, restoration efforts, etc. media is best for my properties, including particle size growers about their products and Sustainability efforts also apply to operation (existing distribution, wettability, pH, electrical the suppliers they are using. the use of packing materials (plas- or planned)? conductivity (salts), physical prop- tics), transportation types and the • Are there any issues erties, and plant growth testing, ENVIRONMENTAL distance supplies travel. or limitations to etc. (Fig. 2). Companies with strong CONSIDERATIONS In addition to sustainability ini- product disposal af- QC programs will retain samples During the past several years, tiatives, also ask potential substrate ter my crop is done? of all substrate batches produced protecting the environment and suppliers about their reputation with • Can I reuse the product for future/ additional cropping cycles? • Have these prod- ucts been tested on the specific crop I am growing? • What technical assistance is avail- able if I encounter a problem during pro- duction that I think is substrate-related? • Is there a cost for technical support or Figure 1 (left): Substrate selection is one of most important production related decisions that any grower has to make, and how to make that limitations on when/ decision does not have to be a guessing game. Figure 2 (right): Professional substrate suppliers most often test or offer testing of heavy metals (A), chemical and nutritional properties (B), physical how to access it? ALL PHOTOS BY BRIAN JACKSON BY ALL PHOTOS properties and plant germination/growth tests (C-D) as part of their technical assistance programs. OCTOBER 2020 | CANNABISBUSINESSTIMES.COM | 59 GUEST COLUMN BY DR. BRIAN E. JACKSON TO LEARN germination or cuttings) ing perlite, rice hulls, pum- or for plant production/fin- ice, wood chips, or others MORE ABOUT ishing in larger containers. that can modify substrate WHICH Propagation substrates porosity and drainage are designed and formu- properties. Other substrate SUBSTRATES lated specifically to meet amendments may include WOULD BE the needs of young plants lime, mycorrhiza, water with developing root absorbing polymers/gels, BEST FOR YOUR systems. Those substrates wetting agents, gypsum, OPERATION, are not appropriate for starter charge fertilizers, larger containers for plant controlled released fertiliz- GROWERS production and finishing ers, and organic fertilizers because of the ratio of (Fig. 4). MAY WANT different components and Growers who are using TO ASK THE the particle size of those hydroponic systems or hy- components, as they brid hydroponic systems— FOLLOWING create different air and substrate in bags or trays QUESTIONS: water properties as well that have nutrient solution as drainage and drying pulsed through the system • Are there advan- properties. For materials and then recaptured—like- tages to having such as mineral wool or ly use more inorganic ma- multi-complete rockwool, it is the size of terials, including perlite, substrates? the slabs and compres- vermiculite, growstones, • What is the stabil- sion ratio that can change and stone/rockwool. The ity of the different those physical/hydrologi- selection of these sub- component/mix cal properties. strate products may differ options and will they Other criteria for sub- than the loose-fill, mostly degrade during my crop production? strate selection include organic substrates, but other growers, variety of physical and chemical the number and type of • Which components are organic and/ Figure 3 (top): Substrate product offerings, delivery properties, regional offerings is likely the same. component offerings and time and scheduling availability, crop longev- (A good substrate or could be used in selections vary tremendous- flexibility, willingness and ity, blending and mixing