What is the Lowest Temperature a Weed Plant Can Survive?

It’s no secret that the weather affects plants. Some plants literally lose all their leaves in the winter while others have frosted leaves. If you’re a weed grower in a place with brutal winters, you’re probably wondering what is the lowest temperature a weed plant can survive in. Here’s what we know. 

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Can Weed Plants Survive the Cold?

Even though weed farms were traditionally associated with tropical climates, they can survive the cold in some cases. However, you have to know what temperature is too cold for the plant and also opt for specific weed plants since they don’t all thrive in colder weather.

According to Royal Queen Seeds, “[L]ook for strains with genetics linked to cooler areas of the globe. Indica-dominant strains and landrace varieties from mountainous areas of Asia, for example, tend to be much better suited to cooler temperatures than sativas.”

In addition to that, Royal Queen Seeds recommend getting auto-flowering seeds. Autoflowering seeds will start to flower when the plant reaches a specific milestone such as size. Therefore, auto-flowering plants are ready for harvest in around 2 months or so. 

However, just because some weed plants can handle cold weather doesn’t mean they can handle all cold temperatures. As a matter of fact, Alchimia says that weed plants exposed to a median temperature below 12ºC, are at risk of dying. So, the lowest temperature a weed plant can survive would be somewhere below 12 degrees Celsius. 

The Seedsman on the other hand says that if the root temperature drops below 15 degrees celsius metabolism and growth stop. 

Even before the weed plant dies from the cold, the cold can cause damage. Alchimia and Royal Queen Seeds say the cold can: 

• Slow down the plant’s metabolism. The colder it gets, the more the metabolism will slow down until it comes to a stop.
• Cause the biochemical and enzymatic processes required for healthy growth to cease
• Negatively affect the root system and affect the uptake of nutrients such as magnesium
• Cause small buds
• Cause mold to grow on the plant
• Trigger hermaphroditism which leads to self-pollination and decreased yield

Can Weed Survive a Frost?

Probably not. Cold weather can kill plants. 

Royal Queen Seeds say, “Unless you live in an area with very mild winters and low rainfall, we don’t recommend growing cannabis outdoors during winter, as you’ll usually end up with sickly plants and/or poor harvests.”

However, they recommend protecting your plant from precipitation (rain and snow) and keeping the soil temperature about 12 degrees celsius using a heat mat. 

Another thing you can do is try to force flowering outdoors. Royal Queen Seeds says, “The easiest way to do this is to cover the plants with a light-proof structure or fabric (like a tarp) during their new “nighttime” hours. This will give them the impression that the seasons are starting to change, and they’ll jump into the flowering phase accordingly.”

However, if you already have weed plants outside but want to move them for the winter without running your yield, you can!

But you have to be careful when moving plants inside. Royal Queen Seeds recommends matching the daylight hours and the temperature inside. If the plant is already flowering, you have to be even more careful when carrying the plants inside.

Royal Queen Seeds says, “If you give them more light indoors than they’ve been getting outside, they may revert back into their vegetative cycle. This process is known as revegetation, and causes extreme stress for the plant.”

The bottom line is, if you’re living in an area with cold winters, it’s probably best to grow your plants indoors. You’re also better able to control humidity, light, and other factors to grow your ideal marijuana plant. A greenhouse is also a great option. 

Signs Your Weed Plant is Too Cold

If you’re wondering whether or not your weed plant is too cold, you’re not alone. Here are some signs to look out for in any plant according to Jackson and Perkins: 

• Discolored, wilted, or droopy leaves 
• Plant becomes mushy
• Plant turns black
• Loose roots 

What are the Best Weed Strains for Low Temperatures?

You can always ask your local seed shop for their opinion on the best weed strains for low temperatures. However, we did some of the research for you. Royal Queen Seeds and Seedsman recommend:

• Alaskan Purple Auto
• Critical
• Northern Lights Auto
• White Widow
• Skunk XL
• OG Kush Auto
• Royal Dwarf
• Northern Lights Auto

Takeaway

What is the lowest temperature a weed plant can survive? It seems that temperatures below 12 degrees Celsius can be detrimental to a weed plant. The good news is that there are many things you can do to save your weed plant such as:

• Moving plants indoor
• Investing in a greenhouse
• Try force flowering
• Keeping the soil warm
• Opting for weed seeds that are better equipped for cold weather