The marijuana plant can withstand extreme weather, but if it does, it may develop abnormalities and growth problems. Although you can’t always avoid bad weather, it is still a good idea to do whatever you can to prevent your plants from getting damaged.
Keep reading to learn how to protect your plants from the dangers that come from growing in extreme weather.
Growing in Extreme Climates:
Growing in the Wind
Heavy winds can cause significant amounts of stress on a marijuana plant – inhibiting its growth. While growers sometimes intentionally stress marijuana plants to improve bud quality, wind damage can easily place too much stress on a developing plant. Instead of relying on the wind to encourage growth in a marijuana plant, focus on the choice of location, your soil’s nutrient content and the quality of your seeds.
Protecting marijuana plants from the wind
In windy areas, it is a good idea to plant crops on the perimeter of your cannabis growing area closely together to serve as a windbreak to protect the other plants. Tying plants to stakes driven into the ground, or constructing a rope and stick fence, are two ways you might achieve this. The drawback, of course, is that those plants will be competing with each other for soil nutrients, sunlight, and water.
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Growing in Cold Weather
Unexpected cold temperature can be devastating to marijuana plants. In fact, the only benefit to cold temperatures is its tendency to discourage pests. Plants grown outdoors need daylight temperatures that are at least in the mid-60s (18*C); otherwise, their growth will start to slow dramatically until it basically stops. In the evenings, temperatures need to be at least in the 40’s (5*C), or there may be tissue damage. Anytime the weather drops below 45*F (7*C) you have a potential problem.
Protecting marijuana plants from cold weather
As a grower, your primary job is keeping your plants alive until the weather takes a turn for the better. If you can maintain a reasonable temperature, most plants stand a good chance of surviving unscathed. When better weather returns, the plants will effectively restart the growing process.
There are a few ways to provide temporary heating until a cold spell passes.
- bring the plants inside and give them a moderate light-on cycle
- use “passive heaters.” To create these, fill up some dark-colored containers with water, let them heat up during the day, and then they will radiate heat at night.
- construct a temporary greenhouse with a wood frame and plastic coverings that will trap the heat (creating a greenhouse effect).
- use propane-powered patio heaters to ward off frostbite. They’ll also burn gas that produces CO2 and water vapor. The added CO2 will promote growth.
All of these methods are easy to set up as long-term solutions for cold weather problems, or they can be quickly taken down with the arrival of better weather.
A smaller scale solution is wrapping individual plants with Polyethylene. This will not only protect the plants from wind and rain, but it will also preserve some heat. Some growers even use high thread count bed sheets. Keep in mind that with this simple method, the cold will eventually make its way to the plants unless you’ve provided them with some source of heat. Forced air heaters can also work but be sure to set the gauge at 70*F (21*C) to avoid overheating and use fans to distribute the heat evenly.
If you know it is going to be cold, you need to be extra careful to keep an eye on your plants. Check on them often and make sure they stay warm.
Is it safe to leave them out?
What if your plants are not yet mature, and the weather is getting cooler? How long can the plants stay outside if the temperatures are becoming too cool?
The answer to this question depends on the amount of available sunlight. As the Earth shifts seasons from autumn to winter, sunlight intensity and overall longevity decrease. Plants that might have been in full light in the summer and early autumn are now shaded for most of the day.
Clouds might also decrease the quality of the sunlight. In the winter, the plants are not allowed adequate light energy and should be harvested to avoid a wasted crop. Even if the buds are not ripe enough to smoke, they can at least be processed for kief, extracts, or for cooking.
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Growing in Humid Weather
Marijuana plants love humidity, but too much of it can cause problems. This includes humidity in the air, as well as wet conditions caused by rain. Mold abounds in rainy weather because water slips into the buds and creates ideal conditions for molds like Botrytis to thrive. The buds tend to hold and hide the moisture and humidity in their crevices, and it can prove difficult to dry them out.
Protecting marijuana plants from humidity problems
Keeping plants dry is the best protection from humidity problems. If you can move the plants or construct an enclosure, then rain will not bother them, but moisture still might. Increasing temperatures in the enclosed area (up to the 70’s F or 24-26*C) could protect the plants and help dry out the buds thereby curbing mold growth. Circulating the hot air with a fan certainly helps as well.
If rain is forecasted as a brief, one-time occurrence followed by a continuation of warm, dry weather, then you can protect the plants by treating them with an anti-fungal like potassium bicarbonate or Serenade before the rain. If prolonged rain is expected, then you might just think about harvesting the plants right then instead of having them just turn into mush. If humid weather is commonplace while the plants are ripening, you might try different varieties with looser, drier buds.
Growing in Hot Weather
For many growers, a hot and dry climate seems to be the perfect environment to grow outdoor marijuana. When there’s heat, you can cultivate the crop all year long without worrying about molds rotting the crop. The plants also benefit from the intense light of the sun which triggers optimal bud production. However, an arid climate also presents its own challenges like drought and extreme heat. This results in a very dry soil that causes a lot of problems to water-loving marijuana plants.
Without the right knowledge and preparation, too much heat can destroy the crop and leave you with nothing to harvest. Fortunately, there are tricks to combat this problem. The key is to keep the plants and their heat-sensitive roots cool and hydrated.
Here are some of the problems caused by hot weather:
- Extreme heat is deadly to marijuana roots, especially in young plants. In addition, the faster evaporation rate in dry places may result in hard and cracked soil. Left unchecked, the combination of hot and dry upper soil can burn the roots and destroy the plants.
- One of the most common issues in a hot climate is heat stress. In mild cases, this can cause the marijuana leaves to start cupping or curl up. You may also see drooping or wilting. If ignored, the condition may become severe, and the plants will stop growing.
- Often, hot and dry climates have long day cycles and as short as five hours of dark hours at night. This can be problematic to marijuana plants since they require at least 12 hours of complete darkness to flower. This unsuitable light and dark cycle may cause further stress to the crop.
Burnt roots, heat stress and unsuitable light and dark cycles can make it challenging to grow marijuana in desert-like climates. The good news is, there are many remedies for these problems, in addition to proper watering.
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Download my free Grow Bible for more more troubleshooting tips
Protecting marijuana plants from heat problems
If you are growing in hot weather, it is essential that you do not let your growing medium dry out. Marijuana plants drink a lot of water when it’s hot. If they don’t have anything to drink, they’re going to dry out by the end of the day. Water your plants as early in the day as possible and make sure they get frequent rehydration during the day. Avoid getting the leaves wet since droplets can magnify the sun’s heat and burn the foliage.
Here are a few other growing aspects that can be altered for hot weather:
The seeds that we use play a huge role in ensuring the success of your marijuana harvest. Because of their places of origin, these strains developed a resistance to the punishing heat of the sun. Of course, they grow even better with a regular watering schedule and some shade from the hot sun. Here are some heat-resistant seeds that are perfect for growing in hot climates.
Sativa, Haze, African and Hawaiian
These strains come from very hot or dry climates, so they are built to withstand tough conditions. This includes having very little water as well as scorching temperatures. In fact, most of these strains can go unfazed for many days with a temperature over 100°F (38°C).
Despite the limited water and high heat, some of these strains can produce high yields. This is especially true with sativas – which can adjust to very short dark cycles. Some also boast high levels of THC.
Recommended strains: Jack Herer, NYC Diesel, THC Bomb, Headband OG, Afghan, and Kaya Gold.
For growers who want to ensure a quick and decent harvest, there are auto-flowering strains. While they’re not designed for hot climates, some of them developed heat-resistant genes due to cross-breeding. Typically, they will begin to flower after 8-10 weeks without relying on a lot of dark hours to trigger the process.
When growing outside, you can grow plants in soil or coco coir. While each has their own pros and cons, coco is more suitable when cultivating in a hot environment. Because of its loose structure, it has root-soothing properties that help plants deal with over or under watering. Hence, it’s the perfect medium to fight heat stress.
It’s also versatile enough to be used as a potting mix or combined with soil. Bear in mind that it’s an inert medium which means it doesn’t contain any nutrients. So, it’s essential to add nutrients in the water from day one. Other than that, the growing experience is very similar to soil.
If you do grow in soil, watch for signs of overwatering. This means your plants will start drooping and wilting no matter how much water they receive. Since hot water contains less oxygen, it won’t be able to revive the plants. Instead, they will drown in it especially if you keep giving it more during the day. So, while constant rehydration is vital, make sure to do it the right way.
To avoid suffocating the plants, provide plenty of drainage in the soil to allow the water to escape. This includes incorporating 30% perlite into the potting mix to make it loose, airy and filled with oxygen. You also want to ensure your water is cool so that it will contain lots of oxygen.
The point of frequent rehydration is maintaining coolness in the roots as well as promoting their formation deep in the soil. During a very hot day, this can help the plant survive even when the upper roots are burnt. To achieve this effect, some growers place water-holders in the soil to provide water once the soil dries out.
You can also create a humidity tray for potted plants. You simply need a wide, shallow tray that’s filled with pebbles or gravel. Next, pour in water up until the top, then place the plant container on the tray. The gravel or pebbles will hold the pot above the water and prevent the roots from absorbing it. As the sun evaporates the puddle, it makes the air around the plant a few degrees cooler.
Marijuana plants fight heat stress a lot better when they’re stronger and healthier. Therefore, you should fortify their resistance by giving them the following essential minerals.
Humic Acid Supplements
This waxy, brown mineral is found in the soil as a result of millions of years of compressed peat. While the plants may already have some of it from the soil, adding extra gives them a much-needed boost. In essence, humic acids protect the roots from water stress caused by over or underwatering.
For best results, some growers combine humic acid with kelp extract. Together, these plant supplements enhance each other’s effectiveness. As humic acids fight water stress, the kelp extract helps the plant combat heat stress.
As mentioned, seaweed kelp extract is a popular solution for heat stress in plants. But aside from that, it’s also found to fight the frost as well as boost growth and yields. It may also improve seed germination, speed up the absorption of nutrients and help plants become more resistant to fungal diseases and insect pests.
Rarely, plants suffer from silica deficiency but adding a little of it can help them a lot, since this supplement strengthens their cell walls so they can beat the heat and other stress. The strong stems are also better able to support heavy buds without breaking. Some popular products are Botanicare’s Silica Blast and General Hydroponics’ ArmorSi.
One of the best ways to deal with heat and its rapid evaporation is to place the plants under partial shade. This way, most parts of the plants are kept from burning while also providing darkness when the natural light cycle does not.
If you can’t bring plants to shade, create it. A simple example is a mesh shade net over the plants or a frame around them that we can throw a shade cloth over. When using a cloth for shade, make sure that it allows airflow to cool the plants down.
If the heat gets out of control, move the plants indoors but make sure that it still gets some amount of light. So, place them close to a window or a light bulb to let them know that it’s still their day period. This will avoid messing up their circadian rhythm and keep them from feeling more stressed.
Stagnant air is one of the greatest enemies of the marijuana plants in a hot outdoor climate. Without fresh air, the plants won’t have a steady supply of carbon dioxide to help create food for energy. And a lack of energy is equivalent to poor resistance to any stress. If it happens during the flowering stage, it would mean low yields of buds.
So, scout which part of the yard has suitable breeze which means just enough to rustle the leaves and not knock the plant down. An excellent example is on the side of a hill where it’s a bit windy but also sunny.
Other helpful tip includes looking for a spot that has surrounding plants which act as a shield from strong winds. They also increase security from people who wander as well as provide shade from the sun.
If growing in a container, keep the roots cool by putting a barrier between the plant and the heat of the sun. You can achieve this with a variety of methods.
- Use a larger container. The extra soil acts as a buffer for the roots. Since there’s more soil, it will take a bit more time for the heat to bake it completely. You can also place the main container inside a larger one to bar the soil from the hot air. This way, the water given to the plant stays in the main container
- Dig a hole. If you don’t have a large container, simply dig a hole in the ground and place the main container inside. This is an excellent strategy to stop the sun from baking the soil and burning the roots.
- Use a container that minimizes heat. You want something that reflects heat while also allowing a good amount of air to pass through. It should also . Fabric pots are typically an excellent choice for containers since it can let air in from all sides, increase oxygen for the roots and allow for draining. Just remember to water enough because these containers also cause the soil to dry out quicker.
Even in extreme weather, it’s possible to grow a successful marijuana crop. All it takes is knowledge and patience since there are many strategies for maintaining a healthy environment for your plants. But for the best results every time, it’s best to start with the most suitable strain. If you are growing somewhere that frequently has cold temperatures, choose a strain that can withstand freezing temperatures. If it is often windy where you grow, select strains that grow dense and hardy.
If you arm yourself with the solutions, the chances of success increase. So, take note of the tips that we shared in this article and have a fun and less stressful growing experience wherever you grow.
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The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]