Climate is a decisive factor when it comes to choosing the right strain to grow outdoors. If you’re lucky to live in a warm and sunny area, your options are practically endless because cannabis plants love the sun.
Nonetheless, heat and humidity (or the lack of it) are also factors which can hinder the development of any crop. Therefore, if you live in a tropical or arid region, you also need to know which varieties are better suited to that type of environment.
Something you quickly learn when you grow or even consume cannabis… is that every strain is unique. Each variety has individual characteristics that not only produce a specific range of aromas, flavours, and effects, but also lead to different growing styles. Some may deal better with high humidity, while others benefit from drier air. Some like higher temperatures than usual, whereas others are more resistant to the cold.
For many outdoor growers, a warm and sunny climate may seem the perfect environment to plant cannabis, as it lets you grow regular or feminised seeds all year round, or even obtain several successive crops of autoflowering seeds. But for a plant that loves water as much as cannabis does, growing in warm climates can also be challenging.
Temperature is one of the main parameters that affect the growth pattern and yielding capacity of cannabis (with the ideal growing temperature being around 23-25°C). As temperature rises beyond these optimum levels, it becomes increasingly difficult for the plant’s biochemistry to function properly, which leads to a slow decline in the plant’s health and development.
Indoors, many growers consider that temperatures between 26 and 29°C are already very high, with 30°C being the absolute limit (and only if this temperature is reached intermittently, and with emergency measures taken to tackle it). Outdoors, however, cannabis plants can endure temperatures of over 35°C in mid-summer, and that’s really when growth becomes exceedingly difficult.
When too hot, the cannabis plant may experience what is known as heat stress, which causes a whole array of setbacks that can hinder development, ranging from root rot to leaf wilting. This is more evident in the early stages, when the seedlings grow very slowly, with leaves that can dry up and turn pale from the very beginning.
Warm climates are known for their heat as well as for their large amount of sunshine. Everybody knows that cannabis plants need sunlight to grow, although too much sunlight can also be dangerous as it can burn them and stunt their growth.
Just as too much heat can be devastating for the plants, excessive humidity can also be dangerous. The main issue here is that high humidity levels facilitate the appearance of mould, fungi, and pests. Many strains require low levels of ambient humidity, particularly during the flowering phase, so they can produce potent and healthy buds. Too much humidity can therefore lead to damage during the most crucial stage of growth.
In addition, as the cannabis plant absorbs more water from the environment, it absorbs less from the nutrient-rich soil, and so the perspiration process slows down, leading to a wide variety of added problems. Plants wither and suffer if they’re not designed to deal with these high humidity levels.
If you grow in a region with an arid climate, with lots of heat and little humidity, you probably won’t have to deal with those problems. However, there are other significant challenges that you could unfortunately be faced with in these circumstances.
If you live in a warm and dry location, the upper layers of the soil may dry up and heat up, which could lead to the roots of the plants getting burnt until they die. In addition, if the plants grow in low humidity conditions, they will take up more water through their roots; and, if the soil has an excess of nutrients, the plants will then absorb too many nutrients too quickly and also end up burning that way too.
Very arid climates can also inhibit plant growth. Plants produce sugars during photosynthesis, but they need to absorb carbon dioxide to transform those sugars into energy. Carbon dioxide is absorbed through the stomata (i.e. the small pores on the plant’s leaves) through a process called respiration. As carbon dioxide enters the plant through the stomata, humidity disappears.
If the plant grows in an area where the air has high relative humidity, it won’t lose much water. But if the air is dry, there will be a significant loss of humidity during respiration. And if your plant doesn’t have enough water reserves, it will try to preserve its health by closing the stomata. This helps the plants to preserve water in the short run, but in the long term it slows down their growth until they eventually die.
In general, the first step that’s needed to grow in these really hot areas is to choose seeds that are designed for cultivation in warm climates, either dry or humid, and which can therefore turn into robust and productive plants under those conditions.
Fortunately, there are many strains that have adapted to these environments. Most of them are sativa-dominant, but there is also a substantial number of perfect hybrids. Sativa strains have a strong tradition of cultivation in Southeast Asia and Central and South America. As such, they are naturally resistant to tropical and subtropical climatic conditions. It’s in their DNA. There are even specific tropical sativa strains that come from Central Africa.
By contrast, indicas originate from the warm, dry mountains of the Middle East and Central Asia, so they require low humidity conditions to flower. In short, sativas may be more suitable for extremely hot areas, whereas indicas may be more appropriate for warm, dry climates.
You can also get an idea of how the plant withstands the heat by looking at how it grows. Those plants that are most sensitive to heat often grow short and bushy (though not always), with wide, opaque, and dense leaves, since they don’t need to worry about things like evapotranspiration and can therefore afford to produce leaves that receive as much sun as possible. Plants that can withstand the heat much better tend to grow tall, elastic, and with narrower leaves, since the thinness of the leaflets helps reduce perspiration and ensures good ventilation on hot days.
The influence of the sun can also be one of the causes of a higher presence of THC, which would act as a protective screen that keeps the plant safe from excessive ultraviolet radiation. This means that plants that come from sunnier areas tend to be more powerful and produce much more complex effects.
Finally, autoflowering strains tend to be more sensitive to heat, as they originated from the subspecies ruderalis, which is native to Siberia. However, thanks to modern hybridisation techniques, there are fantastic autoflowerings on the market that you can now plant in hot areas.
If you grow in a region with a warm climate, you’ll need to consider which strains are better suited to the heat. You can find many suitable varieties in our seed catalogue, but here are some quality examples which will definitely help you hit the mark.
Power Plant is one of the most iconic cannabis sativa strains of recent decades. Its name was chosen for its incredible yielding capacity and crushing effect, but also for being a hardy and reliable strain with the right genetic pedigree to withstand warm climates. It only takes about 8 weeks to flower, which makes it an excellent choice for those who want a quick harvest. And it can also cope with high humidity levels far better than many other strains. In Barcelona itself, BCN Power Plant is a highly appreciated pheno for the cultivation of XXL crops that produce cannabis with an exceptional potency (due to its THC content of over 23%), which translates into a long-lasting high with phenomenal aphrodisiac and introspective effects.
This sativa-dominant feminised seed is another cannabis icon born from the cross of Skunk and Chemdawg. This is a strain that is suitable for beginners, although a little bit of experience always helps to produce its exclusive THC-rich buds (with levels that easily exceed 23%) which showcase a citric and earthy flavour fused with distinct touches of diesel. One of the biggest setbacks you can find is its height, so outdoor environments are best to produce its massive yields. Its natural high resistance to mould and fungi is also very useful for warmer and wetter climates. You can also take some precautions to help make it more resistant to heat, such as growing it in pots so they can be moved during heat waves.
If you’re looking to grow cannabis outdoors in hot weather, the Haze strains are definitely an excellent choice. This one in particular is another legendary plant that grows well in sunny climates thanks to its heritage with origins in Jamaica and South Asia. Amnesia Haze is popular as a daytime medicine, especially for the relief of stress, fatigue, headaches, and general pain. It is also cherished by artistic users because its powerful THC content helps deliver a really creative high. This strain showcases a distinct spiced aroma that is fused with intense flavours of citrus fruits and moist soil. It takes a bit longer to flower, so it’s usually ready for harvest in late October.