How To Grow Cannabis In A Greenhouse

How To Grow Cannabis In a Greenhouse

Growing cannabis in a greenhouse can be cost-effective whilst combining all the best aspects of indoor and outdoor growing. Creating the ideal microclimate for the plants will result in healthier, happier crops with more impressive yields. Greenhouses allow plants to use the sun but combat the other potentially harmful aspects of outdoor growing. They can be controlled, they can be automated and they can be any size or shape to fit budget and crop scale. However, greenhouse growing still takes a little knowhow, set up and research so let’s get started on figuring out our perfect greenhouse. First, we will quickly go over the benefits and potential issues with greenhouse growing.


  • Climate control
  • Personally customizable
  • Can begin growing earlier in the season or harvest later
  • Environmentally sustainable
  • Protection from the elements
  • Protection from pests including bugs and hungry mammals


  • Overheating
  • Excessive humidity
  • Potential costs

Clearly, the pros outweigh the cons for greenhouse growing, and the cons that do exist can be quite easily dealt with. Before we start looking into the more advanced aspects, let’s cover choosing the ideal greenhouse.

Picking the Right Greenhouse

As with any aspect of cannabis growing, we need to tailor our setup to our crop and personal circumstances. We need to think about where we are growing, the climate, our budget and size of the crop. Usually, it’s a good idea to get a slightly larger greenhouse than we need, if possible. This means that once we get used to growing we can always expand our crop without making too many changes.

Before figuring out the size we need we should decide if we want to grow straight into the ground, hydroponically or plant in individual pots. Personally, I would recommend pots since the plants can be moved if necessary and have their own individual source of nutrients. If we are potting the plants we need to have space for tables and storage as well as the plants themselves.

When it comes to the actual material for the greenhouse diffused glass is best because it is sturdy and will not allow as much heat build-up. There are a number of great prebuilt greenhouses on the market that would have diffused glass built-in.


Of course, in order to use a greenhouse for growing, we will need to have a decent outside space such as a garden. Ideally, the greenhouse should face southwards in order to get the most possible sunlight in a day. This is especially important in parts of the world that experience shorter days towards the end of the summer.

Getting Started

First, we need to decide if we are ground growing, pot-growing or hydroponic growing. For beginners, I would definitely recommend using pots because they just tend to be easier. We will need around 7.5 litres of soil per 30cm of plant height. Making sure the plants are portable is best for new growers who may no know the ideal placement for the plants in a greenhouse. This of course is affected by the placement of the greenhouse and the outside environment. If one set up doesn’t work then the grower can always shuffle the plants around for better results.

When it comes to strain choosing there are a number of strains that are especially suited to greenhouse growing. Most greenhouse appropriate strains are smaller and have less branch spread, meaning they can be easily controlled when growing in a restricted setting.

We then need to look into ventilation and heat control, which will prove to be a vital part of greenhouse growing. It is easy for greenhouses to overheat and become too humid. This can lead to mould, rot, plants wilting and smaller yields. Ideally, we don’t want the temperature inside the greenhouse to get any higher than 25 degrees celsius, so in warmer countries, we will need a form of an automated cooling system in place. Equally, in colder countries, we will need to make sure that the greenhouse remains sufficiently warm and that the temperature at night doesn’t drop more than a few degrees. This means the plants may benefit from timed heat pads beneath the pots.

When it comes to the humidity we don’t want the levels to reach higher than 60 – 70% for young plants or 40% for mature plants. As the plants grow they will become denser and therefore be more at risk from mould. This means we need to make sure that the greenhouse is sufficiently ventilated at all times.

Now we can look at extras, these are things that growers may want to put into their setup if they have the extra space or funds. For example, growers that have a decent amount of cash to throw at their greenhouse may want to fully automate. This would include humidity control systems, ventilation systems, backup lighting, heaters, timed misters. Everything the plants need so that we don’t have to mother them. If we can automate we just need to check on the plants regularly to make sure they are happy and healthy.

Other extras include bug screens, security for the greenhouse, fertilisers, extra nutrient solutions and pesticides. These items are not necessary but can make the entire act of growing a little easier.


When using a greenhouse to grow rather than the great outdoors we don’t necessarily need to stick to the growing seasons. If we can afford to put in heaters, extra lights and automated feeding/ventilation we can basically grow whenever we want. Greenhouses are also relatively easy to expand and alter to accommodate larger crops. For many of us, greenhouse growing is also preferable to indoor growing. This can be for a number of reasons, but the over all smell and enormous electricity bills are definitely both factors. As always there is still a lot to learn before we go out and buy our first greenhouse. Always do the research before getting out the debit card, and make sure the set up is perfect for a personal garden.

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