Back to Articles

Growing Cannabis in Extreme Conditions

Updated November 28, 2022

While many people grow cannabis inside, just as many choose to grow outside. Assuming you live somewhere where it's legal to grow cannabis outside, you'll need to take the appropriate precautions to protect your plants from harsh weather. Even indoor growers will have to take some precautions depending on their respective conditions, how strong they are, and their indoor setup.

The following guide should make it significantly easier to protect your cannabis plants from extreme weather conditions.

Growing in Hot Conditions

At first, hot and dry climates seem ideal for growing cannabis outdoors. After all, your plants always get enough sun to optimize bud production, and you can cultivate year-round. However, extreme heat can be problematic, especially given that cannabis plants love and need water.

How Hot Conditions Can Harm Cannabis Plants

The range of damage that heat can cause cannabis plants is broader and more involved than the other extreme conditions in this guide, so it's worth going into more detail.

Extreme heat can kill the roots of your cannabis plants, and this is particularly problematic in younger plants. To hurt the roots even more, extremely hot areas tend to be dryer on average. In this case, there is likely a faster rate of evaporation, which can make the soil hard and cracked. If you do not take care of the soil, the roots may burn causing the plants (and all your hard work) to be destroyed.

Although not always the case, many dry, hot climates have long day cycles, with some only having five hours of darkness at night. While sunlight is essential for cannabis to thrive, the plants also need at least 12 hours of full darkness, so they can flower. Not getting enough darkness can prevent your plants from flowering and advancing their growth. In addition -- it can add to plant stress.

Heat stress is also a very common issue in hot climates. If you're lucky, your plants will just experience mild heat stress, with the leaves starting to curl up or cup. There may be some wilting or drooping, as well. In worse cases, the heat stress can become bad enough for the plants to stop growing completely.

How to Protect the Plants from Heat


One of the very first things to do when growing in an extremely hot climate is to ensure that your growing medium will not dry out. Your cannabis will need a lot of water to handle the heat. If you don't provide enough, they will dry out. Avoid this problem by watering the plants early in the day. Then provide more water throughout the day. Just make sure to get the soil wet, not the leaves. Water droplets on the leaves can magnify the heat of the sun, causing foliage burns.

Selecting and Caring for the Growing Medium

Growing your cannabis outside can be done with coco coir (coconut fibre extracted from the outer husk of coconut) or soil. Coco will be the ideal choice for hot environments. It's looser, which helps soothe roots if you water too little or too much. Additionally, you can combine coco coir with soil or potting mix. Just remember that if you use coco coir to grow your cannabis, then you will need to add nutrients as it does not naturally contain any.

You can grow in soil, even in extreme heat, but you will need to pay close attention. Look out for overwatering, which can lead to wilting, drooping plants regardless of the amount of water received. Hot water has less oxygen, making it harder for it to revive your plants. You will have to avoid suffocating the plants by ensuring the soil has sufficient drainage. Try including 30% perlite in your potting mix. You will also have to use cool water, not hot water, so it has plenty of oxygen.

Choosing the Seeds

If you know your growing conditions are extremely hot, consider opting for seeds of cannabis strains that are more resistant to heat. They will do best with some shade and regular watering, but they are better equipped to handle the hot sun than other strains.

Good options include Hawaiian, African, sativa, and Haze. They come from dry or hot climates, so they can handle tough conditions. Most of these strains can even handle multiple days above 100 Fahrenheit (38 Celsius). Some good examples include THC Bomb, Afghan, Kaya Gold, NYC Diesel, Jack Herer, and Headband OG.

You could also opt for auto-flowering seeds. Although they were not bred or evolved for hot climates, some have gotten heat resistance from cross-breeding. Additionally, they don't rely on sunlight cues to flower.

Using Supplements

You can also help your cannabis plants overcome the heat with supplements, like humic acid, kelp extract, and silica.

Growing in Cold Conditions

If the temperature drops unexpectedly, it can be devastating to your plants. The only positive effect of cold temperatures on your cannabis plants is that pests are less likely to appear. If you grow your cannabis outside, the daylight temperature needs to be at least the mid-60s Fahrenheit (or 18 Celsius). Any lower than this and the plants will experience dramatically slowed growth that can eventually stop.

At night, you want the temperatures to be at least 40 Fahrenheit (5 Celsius) to prevent problems. In reality, however, this figure should be higher as temperatures under 45 Fahrenheit (7 Celsius) have the potential to cause problems.

How to Protect the Plants From the Cold

Your goal is to help your plants survive the cold weather. You can do this by maintaining a temperature that is within the ideal range for cannabis. If successful, when the weather turns warmer again, your plants should be able to restart growing and thrive.

One of the better options, in this case, is to bring your plants inside. If you can do this, set them up somewhere inside with a moderate cycle of light on.

You can also make your plants a temporary greenhouse. Do this with a simple wood frame and plastic coverings to trap the heat inside in what is known as the greenhouse effect.

You can make what are called passive heaters to help you out. Just take dark-colored containers and fill them with water. When the sun is out, let them absorb the heat. At night, put them by your plants, and they should still radiate heat.

If you are really concerned about the plants and want to be sure they remain warm enough, you can also invest in propane-powered patio heaters. As a bonus, these heaters burn gas, which produces water vapor and CO2. That CO2 will help promote growth in your plants.

Another idea is to use forced air heaters, but you need to take precautions if you go that route. Make sure to set the temperature to 70 Fahrenheit (21 Celsius), so you do not overheat the plants. Additionally, you will need to set up fans to ensure the heat is distributed evenly.

For those who don't want to take any of the above more extreme measures to keep plants warm, you can also just grab polyethylene and use it to wrap individual plants. This preserves some heat while also providing protection from rain and wind. An alternative to polyethylene is sheets with a high thread count. The only caveat here is that you need a heat source of some sort. Otherwise, the cold can still reach the plants; it will just take longer.

Choosing Whether to Leave Them Outside in the Cold

One of the biggest questions among cannabis growers who have to deal with occasional cold weather is whether it is even wise to leave the plants outside in the cold. This is a particularly common question in the case of immature plants.

Whether to leave the plants outside depends on how much sunlight there is. In most cases, cold weather is accompanied by a decrease in sunlight, both in terms of longevity and intensity. There is also the chance that the weather will be cloudier, hiding more sunlight.

Put simply, if winter is already arriving, and that is responsible for the drop in temperature, your outdoor cannabis plants are unlikely to get enough sunlight. At this point, you will want to harvest your plants if you can. If they are not quite mature enough for smoking, you could still use them for cooking, making extracts, or turning into kief. If you can safely do so, you could also move the plants inside.

If the temperature has dropped, but your area still has enough sunlight to meet the plants’ needs, then they should be okay. However, you have to take one or more of the above protective precautions.

Growing in Windy Conditions

Dealing with heavy winds can take its toll on your cannabis plants, potentially discouraging their growth. The main issue with wind is the stress it brings to your plants. Some stress is occasionally encouraged to boost the quality of buds, but the stress from wind does not fall into this category. It's uncontrollable and often too strong. Besides, it's better to try to encourage growth and bud quality via carefully choosing the soil nutrients, seeds, and planting location.

How to Protect the Plants From the Wind

If you are planting cannabis in a windy area, then a bit of planning can help protect the cannabis. Plant something else in a way that creates a perimeter around the area dedicated to growing cannabis. These plants will be protective, serving as a windbreaker to prevent the strong winds from reaching your cannabis. You can prevent those protective plants from moving with stakes or a fence made from sticks and rope. Keep in mind, however, that if you go this route, the plants you use as a buffer or protection will compete with your cannabis plants to get water, sunlight, and soil nutrients.

Another option that does not involve competing for soil is to clip your cannabis plants. This should encourage the plants to adapt and get denser. That, in turn, should improve flowering. Just keep in mind that this method can slightly limit your harvest.

Growing in Humid Conditions

While cannabis plants do well in moderate humidity, too much can be damaging. The humidity can be problematic, whether it is just in the air or it is due to rain that caused wet conditions. Rainy weather, in particular, leads to the risk of mold. The water gets into the buds in this weather, making the ideal conditions for mold to thrive. Unfortunately, buds are great at holding humidity and moisture inside, thanks to their nooks and crannies, so it is very hard to dry them out and overcome humidity.

How to Protect the Plants From Humidity

The absolute best way to protect your cannabis plants from humidity is to keep them dry.

Try putting your plants in an enclosed structure or build one around them. This will protect them from the rain, which would worsen the humidity. Just keep in mind that an enclosure will not stop moisture from causing problems to your plants.

To minimize the moisture problems, try increasing the temperature within your enclosed space to the 70s Fahrenheit (24 to 26 Celsius) level. This could help dry the buds and, in turn, reduce mold growth. Take this a step further and use a fan to circulate the hot air.

In the case of just a single instance of rain instead of regular humidity or rain, then you have more choices. Assuming the weather will go back to dry and warm after the storm, you can use an anti-fungal treatment before the rain, such as potassium bicarbonate.

If the rain is going to last for a long time, then you should see if you could harvest the cannabis already. Otherwise, the plants may get too damp and humid. If you cannot harvest them yet, then you would want to enclose them with proper airflow.

You can also plan ahead to overcome humidity if you want to grow cannabis, but know your area tends to be humid. Opt for cannabis strains with drier and looser buds as they will retain moisture less, reducing the risk to the plants.

Grow with us.

Get articles like this and cannabis seed deals.