Growing marijuana during the winter

Published Feb 13, 2019 03:15 p.m. ET

Cannabis plants are one of the strongest and most resilient plant species in the world. While we know that various strains are adaptable to different climates according to their genetics if you live in a region where night temperatures drop below 15 C than growing outdoors is likely not in the cards for you. Some areas like California, Australia, Jamaica, Columbia, or just about anywhere in the Mediterranean are fortunate to experience relatively lengthy growing seasons that go beyond the summer months. For those who live anywhere that has a more dramatic range of temperatures an outdoor plant is impossible to pull off. Marijuana and frost can go together in small amounts that induce a temporary vegetative stage, but cold, blustery conditions are no place for a cannabis plant to thrive.

Growing weed in the cold

Some cannabis plants can do exceptionally well in cooler conditions, but they must not ever see temperatures that drop below 15 C to succeed. This makes the chance of growing weed in the cold not worth it for many; as a small dip in temperature, one night can kill an entire crop in an instant. If you do choose to grow in colder climates than nightly precautions should be taken. Precautionary actions of wrapping or bringing in plants to avoid extended exposure to cold are the most effective protection.

Winter cannabis strains

Winter cannabis strains are known for their ability to thrive in some of the harshest conditions. Their ability to do so is ingrained within their genetics but remember, even the toughest winter cannabis strains will suffer if temperatures drop too low. There are two different characteristics you will want when selecting the best winter cannabis strain.

Autoflowering - Autoflowering marijuana strains are the most recommended for growing in colder climates. Not only can they withstand lower than average temperatures, but they can also go from seed to ready to harvest in as little as eight weeks. This makes them ideal for those trying to pull off a crop before the coldest part of winter hits. Can autoflowers grow in winter? Well, that depends on the region you are growing within. If you are confident in the average temperatures staying out of the danger zone, then yes.


Ruderalis - Ruderalis genetics are often used in the making of autoflowering cannabis strains. The gene the Ruderalis provides allows the marijuana plant to begin flowering within 30 days.

Winter cannabis risks

The most significant risks you will face when growing weed in the cold are the environment and mold. The temperatures can be lethal if extended beyond the danger zone even if it’s only for a couple of hours. Mold is an even bigger problem in more frigid temperatures than it is in warmer climates. High levels of RH and low temperatures make an ideal environment for fungus to thrive. This is the biggest threat once the flowering stage begins, as the spores will stick to the plant materials and grow from there. The best way to avoid this is to begin as early in the season as physically possible and to use pots or planters that can be relocated if there is a sudden shift in weather.

Growing winter cannabis in a greenhouse

Growing marijuana in a greenhouse in winter is one of the most common methods used to cultivate winter cannabis. This is because the heat from the sun and other sources can help to shield your plants from any negative effects or extreme cold exposure. Growing marijuana in a greenhouse in winter requires only a handful of necessities to thrive. Grow lights that emit powerful light rays also tend to put off quite a bit of extra heat which can be contained within a well-sealed greenhouse. Winter cannabis strains will help to ensure the success of your crops with their ability to withstand average temperatures between 15 C and 20 C. HPS light fixtures and MH bulbs not only put off heat, but they will also require a decent cooling system that more frigid temperatures can provide making them perfect for a greenhouse in the winter.  



Related posts