How To Grow Cannabis In a Greenhouse
Despite the fact that the popularity of cannabis is on the rise what seems like everywhere these days, many enthusiasts and consumers find themselves in places without either dispensaries or the legal framework to safely obtain some quality buds, which would partially explain the exploding popularity of domestic cultivation. This is a reliable and (relatively) inexpensive way of ensuring access to your medicine, but new growers are faced with a slight dilemma: what is the best method to cultivate cannabis at home and how do I go about it?
The three fundamental ways are: outdoor as mother nature originally intended it, indoor as resourceful humans have discovered (and perhaps even perfected) or in a greenhouse as a combination of the first two. Multiple factors can play a role in determining which setup is best for you, including things like experience, budget, security, available resources, etc., but in terms of producing an abundant and quality end product, we’ll focus on the greenhouse method as it seems to provide the most bang for your buck without the exorbitant price tag of indoor growing and without the risk of being at the mercy of mother nature’s whims (floods, droughts, pests, etc.).
Why Grow Cannabis in a Greenhouse?
Growing in a greenhouse provides several advantages over both the indoor and outdoor method without breaking the bank, so regardless of your budget, you can produce outdoor amounts of cannabis with indoor quality buds. So what makes greenhouse growing special?
First of all, it provides the basics that a cannabis garden needs: air, light, and warmth. They take the sun’s energy so that plants can conduct photosynthesis and since they can be easily opened up, they also provide plenty of carbon dioxide for plants to breathe in, something that is often artificially supplemented in indoor setups. Since greenhouses get their heat by trapping the sun’s radiation during the day, this means that they can also be used during the winter, though light supplementation might be a good idea if there are only a few hours of daylight available that time of the year. The radiation released by plants stays in the greenhouse, keeping the air at a steady temperature. What this means is that you can grow year-round and are not tied to a single harvest as you might be with a traditional outdoor grow.
Another advantage that greenhouses have over growing outdoors is the element of protection. Without any form of protection, be it a glass roof or a plastic tunnel, plants are subject to whatever nature throws at them in the form of dangerous precipitation such as hail or heavy rain or in the form of pests and predators (including the human variety) that can quickly destroy an entire crop if left unchecked. Not to say that greenhouses are a 100% guarantee against anything bad happening to your crop, however the control over your crop and the resulting yields that a greenhouse provides are unmatched by the other two options. With the added protection against storms, greenhouses also allow for an extended growing season, which means that equatorial sativa varieties can be fully mature without having to rush a harvest before the winter. This allows not only for more cannabis year-round, you can also diversify your strain portfolio.
Greenhouse Growing Basics
It may seem a little complicated at first and some greenhouse setups are on the fancy, technologically advanced side of things, but the premise is quite simple: use the sun’s natural (and free) energy to provide light to your plants and heat your grow space. With the greenhouse’s glass or plastic covering, heat and humidity get trapped and the space stays warm and humid. These conditions can then be controlled by the grower as needed. The space can be ventilated to maintain a certain humidity or to reach a specific temperature.
Watering and feeding are the responsibility of the grower as well since the space is protected from precipitation. Depending on the circumstances, it might be necessary to supplement your garden with artificial light, particularly if growing during the winter when there is less natural light available. On the flip side, tarps and/or blackout screens may be required if you are using the light deprivation technique to have multiple harvests and need to switch to a 12-hour day/night cycle quickly.
As is the case for cannabis plants in general, you will also want to start your garden with some good genetics, in other words quality seeds from a trusted breeder or seedbank. With an extended growing season, this means that you can also grow a range of sativas with a frustratingly long flowering time and not have to worry about a surprise snowstorm in late fall/early spring.
In addition to good genetics, your garden will need a reliable medium to flourish and in the case of greenhouse growing, you have two options to choose from: pots or directly in the ground/raised beds. The benefits of growing in pots include increased mobility for your plants if they need to be moved for whatever reason and absolute control over what goes into the soil, namely water and nutrients. Much like indoor setups, this can produce top quality buds with impressive terpene profiles thanks to the personal attention given to the garden by the grower. However, with this method, growers will have to attend to their garden more regularly as plants that are confined to smaller pots will be a little thirstier and hungrier more frequently than those growing directly in the ground.
If you do decide to plant directly in the ground or in raised beds, the additional space for plant roots to grow will help with water and nutrient conservation and growers will be able to check up on their garden with less frequency, in some cases even up to two weeks between watering/feeding. If using an automated watering/feeding setup, growers will have even more free time to focus on other aspects of their garden.
Maximizing Your Greenhouse Setup
There are many good reasons to start growing in a greenhouse, but one of the biggest arguments for doing so is the ability to manipulate the plant’s life cycle. As mentioned above, light deprivation is a technique that is growing in popularity as it allows for multiple harvests in one growing season. The idea is to trick the plants into thinking it’s flowering time by cutting off light for 12 hours until they’re ready for the chop. While still possible with outdoor plants, it is much easier to pull a tarp or other covering over your roof than to do so with monstrous tree-sized plants growing directly under the sun.
If growing in the winter, you can still grow plants with supplemented light, thereby extending your growing season even further. Another trick that can be used to get several harvests in one season is the use of autoflowering varieties. Since autoflowers are not photoperiod-dependent, they will automatically enter flowering and finish faster than they’re photoperiod cousins, which means no light deprivation will be needed. If you get your hands on a big-yielding autoflowering variety, you can produce yields that will rival the quality of photoperiod strains in half the time.
Greenhouse Safety & Security
Greenhouses can be of any size and therefore are suitable for all levels of growing, whether you’re a small-scale novice or an experienced commercial grower, however a few things should be taken into account regardless of the scale of your garden or your experience. Security and privacy are going to be top priorities for many growers, particularly in places where cannabis is still illegal.
Secure your greenhouse
A greenhouse will provide a basic level of privacy and security for your garden, however in this case you cannot be overcautious. Installing additional locks, cameras and alarms will make it that much more difficult for burglars, vandals and the like to get to your crop. Having a greenhouse in an area difficult to access physically is another theft-deterrent, though not every grower will have that option.
Another security issue to take into account is odor control. Towards the end of the cannabis life cycle, fully flowering plants will produce a smell noticeable from far away, so odor control is a must. In-line ozone generators have been used successfully in the past and many companies now offer various products such as blocks, sprays and gels to neutralize the pungent smell of cannabis, so finding the right type of odor control has become that much easier.
Consider heat and humidity
Another aspect to consider when choosing a greenhouse is ventilation. During the warmer months, things will get hot and muggy inside, which means there will be the potential for mold to develop so proper airflow for your plants is key. Some greenhouses come with panels where you can open the sides of your grow space to let fresh air in. In other cases, air has to be pumped through with exhaust fans.
Keep your greenhouse clean
As with any setup, regardless whether indoor or outdoor, cleanliness is also a must. By keeping your greenhouse clean, you will keep away pests, mold and other pathogens that can quickly destroy an entire crop.
Types of Greenhouses
Not all greenhouses are built the same, though they share a lot in common. The market for greenhouses is expanding thanks to the loosening of cannabis restrictions and different growers will have different needs. Some of the more common greenhouses used these days include the lean-to (which shares a wall with another structure to provide support for the roof), even-span greenhouses (which include tunnel-like hoop houses), uneven-span greenhouses, ridge-and-furrow greenhouses as well as retractable roof greenhouses. Some companies have even installed light-deprivation elements/tarps in the roof mechanism to make light dep all the more convenient.
Different materials can also be used for the covering or glazing. Glass is generally regarded as the best material for growing in a greenhouse, though other popular materials include polyethylene sheets, polycarbonate structured sheets (which are for good light transmission), acrylic structured sheets and fiberglass sheets. All of them have their advantages and disadvantages, so choose according to your needs as well as your budget as the costs can greatly vary as well.
Growing in a greenhouse doesn’t have to be complicated or expensive at all. With the right amount of research and planning, you can design a grow space that will consistently provide high-quality yields that will rival any indoor setup but with the cost, time and energy-saving benefits of growing under the sun. It can be challenging at first, but there are too many arguments not to give it a try. Are you ready to take your growing skills to the next level?