Professional Marijuana Grower November-December 2018 Issue

Connected Greenhouses This is another example of a freestanding design, but it is geared towards large-scale production. Essentially, they are multiple greenhouses that are joined together. The large, undivided space allows for more efficient heating and cooling throughout the facility, but there are usually different sections to house and tend to seedlings, clones, and plants in different stages of growth. Just like an indoor grow room, greenhouses do have space limitations. Whether growing in a small glass greenhouse or a huge and long poly tunnel, space needs to be planned to ensure your plants have room to catch light when they start to get big. When planning, remember that indica plants are shorter, yet bushy, with wide and fan-like leaves, whereas sativa strains can grow to great heights and are usually more on the slender side. Temperature Cannabis like many crops likes different temperatures at different stages of growth. The air temperature in the greenhouse should be adjusted according to the level of light. In general, winter crops grow best at tempera- tures of about 65° to 85° F in the daytime and 60° to 75° F at night. On cloudy days, these temperature ranges should be somewhat lower, since the plant is not manufacturing as many sugars as usual. Your green- house heating and cooling systems need to consider the temperature needs and controls for each zone. Typically, the heat provided by the sun combined with the natural heat given off by the plants as a result of the greenhouse effect, should keep plants warm during cold weather in mild climates. No matter what kind of marijuana greenhouse growing techniques you use, you must be sure that you have proper ventilation. The temperature has to be kept at a steady level, even if you are using the hydroponics method. In extremely cold locations, it is advisable to equip your cannabis greenhouse with a heating system that controls the greenhouse temperature. MULTIPURPOSE GREENHOUSE DISINFECTANT & DISEASE CONTROL • Disinfect pots, trays, benches, tools, etc. • Algae control on walkways, pots, evaporative coolers, soil • Spray on plants to control bacterial, viral and fungal disease • Excellent wetting agent • Cost effective, pleasant odor and environmentally friendly MARIL PRODUCTS, INC. 15421 Red Hill Ave. • Suite D • Tustin, CA 92780 USA 714-544-7711 • 800-546-7711 • www.physan.com 40 • Professional Marijuana Grower Likewise, cooling and ventilation can be critical to pre- venting heat buildup during the warmer months. Humidity Keeping your plants at the correct humidity levels is key to keeping your plants safe through the seasons. Most young plants and seedlings tend to react better to a slightly more moist environments or 60 – 70% humidity. As the plant matures, it is best to slightly dial down the humidity, shooting for around 40% by the time your plants are fully flowered (around week nine). Too much humidity invites disease and too little dries out the plant and hinders growth. Cannabis in the vegetative stage actually likes a higher humidity level and prefers lower humidity when in flower. Ventilation Every greenhouse needs to have a ventilation system and circulation fans installed to produce optimal grow- ing conditions. Ventilation is the exchange of inside air for outside air to control temperature, remove moisture, or replenish carbon dioxide (CO 2 ). Greenhouse ventila- tion breaks down into two main categories: 1) natural ventilation covers roof vents, sidewall vents and rollup sides, and 2) forced air ventilation requires mechanical systems like exhaust fans, and sometimes cooling pads. Exhaust fans should be sized to exchange the total volume of air in the greenhouse each minute. The total November/December 2018

Professional Marijuana Grower November-December 2018 Issue | Page 40