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how to grow weed in your greenhouse

How to grow weed in your greenhouse

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.

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.

Cannabis cultivation can take place indoors, outdoors, or in a combination of these two places: the greenhouse. A greenhouse can be as small as a tool shed or as large as an industrial building. If you have enough space to accommodate even a small greenhouse, this option may propel your cannabis cultivation to the next level.

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.

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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.

A marijuana greenhouse also puts you in control of two primary factors in successfully growing marijuana plants.

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

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Free-standing greenhouses: From a simple walk-in greenhouse with room for a couple of plants to the massive connected behemoths set up by commercial growers, free-standing greenhouses are what most people picture when they think of a greenhouse. They are apex shaped, like a house, and consist of metal or wood frames and glass, fiberglass, or plastic panels. Many have roof and/or side panels that open to allow for ventilation. This may be the most expensive option, but it also has the most room for plants while still allowing for location flexibility so growers can move it to best capture the sunlight. Inexpensive free-standing models start at less than $100 but they may not be very durable. Sturdier models cost closer to $1,000 and prices go up from there.

Whether it’s a simple walk-in greenhouse or something more elaborate, check local laws to see if building permits or other formalities need attention before you start building.

How to grow weed in your greenhouse

Many greenhouse growers enjoy large harvests of over 100g (dried buds) from each autoflower plant. The protective environment of a greenhouse protects the autoflower plants from the worst of the weather and the extreme low temperatures which can occur especially in early spring and autumn.

Autoflower seeds in greenhouses

Just as with outdoor grown cannabis, the shift towards shorter days during the summer is a signal to the cannabis plant to start flowering and produce the desired female buds.

How large do cannabis plants get inside a greenhouse?

Some growers equip their greenhouses with a ‘darkening’ system. Essentially this involves using dark blinds/curtains to create blackout conditions inside even when it is sunny outside. This can be used to simulate short summer days and ‘force’ the plants to start flowering and producing buds much sooner than normal. Although this involves extra expense it is one way of accelerating greenhouse weed production. The grower simply uses the blinds to reduce daily light exposure to 12 hours (or less) and the plants in the greenhouse respond by flowering.

How to grow weed in your greenhouse

Ventilating the Cannabis Greenhouse

Humidity and temperature affect each other. When it is warmer, warm air hold more water than cold air. For cannabis to grow nicely the temperature and humidity levels need to be in an ideal range for the plants to thrive. When the plants are in the seedling stage the humidity can be between 70% and 80%. Some growers will tell you that seedling and clones prefer the level to be from 65-70% humidity. The high humidity is necessary because the roots are not yet developed, and the plant will take in water through its leaves.

As a grower it is important to monitor the pH levels of the water you use to feed your plants. pH is the measure of how “acidic” or “alkaline” something is on a scale off 1 to 14. “7” is considered neutral. Small sickly buds may be the result in part of improper pH levels. A cannabis grower can measure the pH of water sample using a special p tester drops or a digital pH pen. When the pH is within the correct range, the plants can get the most out of all the nutrients, and their buds will reflect it. If the pH at the roots is too high or low, the plant can’t properly absorb the proper nutrients.

Ample Light

So you are growing cannabis in a greenhouse. Most of this information is nothing new unless you are new to cultivating cannabis. Here are a few recommendation to stay on top of during your cannabis growing adventure.

As a new grower, don’t try to grow without sufficient light. Did you know that the plant yield is in direct proportion to the amount of light it receives? There are three types of lights:

Considerations When Growing Cannabis in a Greenhouse

Once the plant is flowering, the humidly needs to be lowered to 40-50%. This is considered critical by some growers. At this time you may lower the ambient temperature. With the lights on a good temperature range is 68 to 78.8 degrees Fahrenheit.

It has been said that new cultivators are apt to harvest the crop too early. If you harvest too early, when the trichomes are still clear, the THC will not be as strong. Ideally one should wait until a more milky color has filled half of the trichome heads.