What is the construction principle of indoor cannabis greenhouse?

Types of large-scale cannabis cultivation

Today, most industrial cannabis production falls into three categories: indoor, greenhouse and hybrid. Indoor growing operations are fully enclosed, warehouse-like buildings, relying entirely on artificial light and environment control. While it's true that indoor setups make for the easiest environmental control, that comes at a cost. The cost for the extensive amount of artificial light required in an indoor operation alone can be a massive expensive. For example, for a 3,600 square foot indoor grow in Colorado, where electricity costs about 10 cents per kilowatt hour, it would cost about $5,880 in electricity for lighting alone to raise 144 plants to the flowering stage.

Greenhouses provide a cost-efficient alternative to an indoor growing facility. Commonly used as a way to protect plants from the elements and provide some climate control since the early 20th century, a greenhouse is an enclosed structure with a transparent roof and walls that allows the light and heat of the sun in while creating a microclimate for optimal growth.

In addition to greenhouses and indoor growing spaces, a third option that has gained popularity in recent years mixes elements of the two. Hybrid greenhouses have the permanently constructed walls of an indoor operation with the transparent ceilings of a greenhouse. These structures offer the durability and much of the insolation of warehouses while still allowing growers to utilize free, efficient solar light.
So why go with a greenhouse?

Of the three options, traditional greenhouses are still the most cost effective. Greenhouses are not permanent structures, which means that in most cases they receive construction and expansion permits much faster than fixed structures. Greenhouses are significantly less expensive to construct than warehouses or hybrid greenhouses with their permanent steel and concrete structures. Greenhouses can arrive to the site largely prefabricated, needing only to be assembled, which saves significantly on construction labor costs.

Even the most efficient indoor lighting setups can't compare to the most powerful light source in the solar system, which just so happens to be 100 percent free. Direct sunlight on a clear day provides light levels of about 1,000 to 1,500 micromoles per square meter per second, compared to 500 to 800 micromoles per square meter per second from a 1,000 watt high pressure sodium lamp.

While of course solar light isn't available all the time, cannabis companies using solar still enjoy a solid 12-18 hours each day free from having to run the costly high-pressure sodium lamps. This can save growers as much as 50 to 90 percent in energy costs depending on the time of year and other factors.

Not to be overshadowed by the cost savings, that saved electricity significantly lowers the environmental footprint of a growing operation. A 2012 study by Evan Mills, a senior scientist in energy technologies at the Lawrence Berkeley National Laboratory, found that indoor cannabis grow operations accounted for one percent of energy use in the United States. As more jurisdictions move to build legitimate cannabis industries, there's pressure from governments and the public to ensure that the cannabis industry is environmentally sustainable.
Building the Ideal Environment

1. Geographic location. I cannot overstress the importance of this point. Not all greenhouse manufacturers or cannabis growing consultants have experience in different geographical locations. Many people will try and sell you the greenhouse that has been successful in Colorado, but if you are in Southern California, Puerto Rico, or Alaska, the greenhouse you need is going to be very different.

Your outside temperature fluctuations, wind speeds, humidity levels, snow loads, and light levels all factor into what equipment and the style of structure that is best for you and your crop.

2. Inside greenhouse temperature. Cannabis like many crops likes different temperatures at different stages of growth. As a generalization you want your greenhouse temperatures between 65 to 85° F. Your greenhouse heating and cooling systems need to consider the temperature needs and controls for each zone. Inexperienced consultants may tell you that you don't need as much heating because the lights generate a lot of heat, but as you will see in the sections below, cannabis typically wants only 18 or 12 hours of light, so your coldest night time temperatures will still typically have no lights on at all.

3. Managing humidity inside a cannabis greenhouse. We all know the effects humidity has on plants. Too much, and you invite disease, too little and you dry out the plant and hinder growth. As with any crop, knowing the humidity that the plant thrives in is important when designing a greenhouse. While cannabis in the vegetative stage actually likes a higher humidity level, it prefers lower humidity when in flower. Greenhouse manufacturers who understand this can help you build flexibility into your greenhouse designs. There are several dehumidification units on the market, and for areas needing the ability to add humidity misting systems can be added into the greenhouse design.

4. Ventilation recommendations for greenhouses tie into temperature and humidity needs. Greenhouse ventilation 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. Please note that cooling pads are not a good option for high humidity regions.

In addition to ventilation to remove hot air from inside the greenhouse, most greenhouse growers put airflow fans inside the greenhouse to circulate air movement which is good for keeping healthy plants. Greenhouse manufacturers can provide you with a greenhouse plan layout showing fan locations that optimize airflow coverage.

5. Adjusting lighting levels will increase yields in a cannabis greenhouse. One of the biggest advantages that greenhouse growing offers over indoor growing is that greenhouse plants benefit from natural sunlight. Not only does sunlight naturally provide the plants what they need to grow, it doesn't cost the grower any money to power. Having said that, when cannabis is in the vegetative state it performs best with around 18 hours of light. For this reason we recommend greenhouse growers include supplemental lighting in their cannabis greenhouse plan. Make sure your greenhouse lighting plans satisfy year round production if you want to optimize yields.

6. Flowering cannabis needs blackout. While the vegetative stage enjoys greater light levels, for flowering longer periods of darkness are desired. Ensuring 12 hours of uninterrupted darkness inside your greenhouse will force the marijuana plants to flower according to your production schedule. This is best achieved by utilizing blackout curtain technology, also known as light deprivation in the marijuana industry. Blackout has been commonly used in production greenhouses for decades for poinsettias, kalanchoes, mums and other
crops that benefit from photoperiod adjustments.

Blackout curtains can cover flat roof areas running truss to truss on gutter connected greenhouses, or they can be sloped to follow the roof line of freestanding greenhouses. Remember to cover sidewalls and door openings, and at GGS we provide light traps for exhaust fans as well.

7. Cannabis plants thrive with CO2 enrichment. If you are using a hot water heating system CO2 can be pulled off the boiler. In other cases you may wish to use liquid CO2 to dose your cannabis crop.

Additional considerations include connecting your greenhouse to warehouse and office facilities for packaging, shipping, and other support functions. There are other unique requirements for cannabis that you will not have encountered with typical horticultural crops, such as drying rooms and vaults. Work with a company that has the expertise to help you.
Here is the 420 on Growing Marijuana in a Warehouse:
A warehouse facility environment provides the cannabis grower with maximum control, and therefore the most reliable consistent marijuana crops can be produced in a properly designed warehouse grow room.
Without natural light, warehouse grow rooms depend on intelligent grow lights which need to replicate the parts of the sunlight spectrum that the marijuana plants need at each stage of growth. Lighting is a key component in an integrated system.
Air filtration and circulation systems are essential for controlling heat buildup, and eliminating exhaust odors. It is critical that the air circulation in a marijuana warehouse is designed in conjunction with the grow lights because lighting systems emit large amounts of heat.
There are various irrigation systems for growing marijuana appropriate for growing in a warehouse: including drip irrigation, hydroponic flood benches, or trough benches.
The irrigation system should be designed in conjunction with a nutrient management system for maximizing the production yield of the cannabis plants.
The brains of the complete marijuana growing system whether a warehouse grow op or a greenhouse production facility is our environmental computer. The computer control systems for a marijuana warehouse control and monitor all the nutrients, lights, air circulation, and irrigation needs of the plants, it is designed to maintain the exact environment needed for as many different growing rooms, cloning rooms, flowering rooms as you need. With our system, all of this can be conveniently run from your smartphone.
Custom made benches (growing tables) that not only maximize the efficiency of your growing space, but that are made of materials that are compliant with Health Canada's requirements, or the local code that you need to meet.
De-humidification to optimize your growing environment.
Computer controlled CO2 injection and monitoring.