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growing weed in a greenhouse

Growing weed in a greenhouse

Solar radiation (energy from the sun) passes through the transparent walls of a greenhouse and heats up soil and plants, keeping a greenhouse warm even when the outside air temperature is cold.

Recreating the Cannabis Life Cycle

Greenhouses also provide cover for your plants, as heavy rains will damaged them and cause them to rot if too much moisture is trapped inside the buds. Some can also have dehumidifiers, heaters, air conditioners, and fans, all of which will also regulate the climate.

Weather and Climate Control

In turn, soil and plants release energy as infrared radiation, which can’t escape the greenhouse, so the trapped heat warms the air.

Growing weed in a greenhouse

Using Department of Energy, Environmental Protection Agency and industry data, we found that growing pot indoors leads to higher greenhouse gas emissions in the Mountain West, Midwest, Alaska and Hawaii than compared to the Pacific and Atlantic coasts. This is because climates are milder on the coasts, so you need less heating or air conditioning and because the electric grids use more clean energy

But the biggest energy use comes from the need to constantly bring fresh air into growing facilities. All of this outside air needs to be treated so that it is the correct temperature and humidity. This is a very energy-intensive process since the air exchange rate is typically so high.

The lights used to grow weed indoors use a lot of electricity, but facilities require a lot of energy to maintain a comfortable environment for the plants. That means air conditioners or heaters to maintain proper temperatures. Producers also pump carbon dioxide inside to increase plant growth. This accounts for 11% to 25% of facilities’ greenhouse gas emissions.

Why it matters

We aim to show greenhouse gas emissions per serving of tetrahydrocannabinol, the chemical that produces the “high.” Our preliminary results show that one serving of THC – roughly 10 mg of dried flower – is likely to have higher greenhouse gas emissions than a serving of beer, wine, spirits, coffee or cigarettes, regardless of the location the weed was grown.

Currently, there is little to no regulation on emissions for growing cannabis indoors. Consumers aren’t thinking about the environmental effect either. As a whole, this industry is developing and expanding very quickly without consideration for the environment.

The big idea

Policymakers and consumers aren’t paying much attention to environmental impacts of the cannabis industry. In Colorado, the weed industry accounts for 1.3% of the state’s total annual emissions. This is similar to emissions from coal mining and trash collection for the entire state.

The cannabis industry is so new that researchers don’t even know how much is grown indoors. Additionally, every indoor operation is unique. Some are old warehouses using outdated equipment, while others are much more energy-efficient.

Growing weed in a greenhouse

Invest in top-quality soil as this will impact the entire growing process. Photo by: Gina Coleman/Weedmaps

The key word when it comes to growing cannabis in a greenhouse is control. Greenhouse cultivation provides the natural sunlight, fresh air, and other benefits of growing outdoors while eliminating the unpredictability of Mother Nature. Periods of rain and wind can wreak havoc on your weed garden, but a greenhouse protects plants from the elements. Likewise, pests, bacteria, and diseases are less likely to invade your plants in the shelter of a greenhouse.

If DIY is not your style, think about your budget and how many plants you’ll want to grow then decide how much space you’ll need for plants, climate control, and the rest of your greenhouse setup. Armed with that information, consider the options below.

The ideal spot for your DIY grow room will be facing the sun. A slightly shaded area is fine, but make sure nothing is keeping the natural light from reaching your greenhouse. The more hours of light, the bigger the yield.

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Equipment: From irrigation to climate-control systems to exhaust fans, the supply list for a cannabis greenhouse can be long. But once you make an initial investment, most equipment will last season to season. Down the road, don’t be afraid to add things like heating or lighting if your cannabis plants seem to need it.

Polytunnel: These elongated, dome-topped greenhouses have an aluminum frame and a covering of polythene. They are usually big enough to walk into but not as sturdy as actual greenhouses. Accordingly, polytunnels are on the lower end of the price range, starting at around $160. These can be durable but do need some maintenance, especially replacement of the cover every three to five years.

Once you have the best greenhouse for you, it’s time to put your cannabis cultivation skills to the test. Here are the most important aspects of growing top-quality weed in a greenhouse.

Benefits of growing marijuana plants in a greenhouse

Soil: First and foremost, invest in top-quality soil as this will impact the entire growing process. Pick a nutrient-packed soil that contains organic substances like compost and worm castings. Pay attention to the pH levels of the soil as well — aim for a range of 5.8 to 6.3. Other qualities to look for in soil include good drainage ability, high oxygen levels, and effective water retention. You could also make your own super soil.

Attached greenhouses: These are usually shaped like a house and attached to the existing wall of a house, garage, shed, or barn. This greenhouse option is made of metal or wood framing with glass, fiberglass, or plastic panels. While they might be slightly less expensive than free-standing greenhouses because one wall is already built, the location of attached models is dictated by the location of the existing structure. Prices vary greatly depending on location, size, and construction materials.