Cannabis is one of those plants that can surprise you, even after years of growing it in a variety of conditions. Every so often you’ll come across something weird that your cannabis plant is showing. Often, this is because a lot of issues that cannabis can have can be caused by one or many things.

Red stems on your cannabis plants are a problem that can be the result of one, or a few things that need attention with your cannabis plants. Sometimes it’s nothing at all and a result of something beyond your control. It then becomes a case of detective work and once you put all the pieces together a solution will be visible.

Red cannabis stems could be caused by a few things including your grow light being too close, nutrient deficiencies caused by incorrect measure or PH, temperature fluctuations, and even due to the genetics of your plant. It’s important to take additional steps to ensure you’re implementing the right solutions.

As you can see, identifying that your plants have red stems doesn’t allude to a solution right away. You’ll need to dig a little deeper and revisit a few parts of your grow setup to eliminate all other possibilities. Let’s look into why your cannabis stems could be turning red.

What Causes Cannabis Stems To Turn Red?

Many causes could determine why your cannabis plant turns red. Identifying other markers will be beneficial in your final diagnosis.

Your Lights Are Too Close

This is a common one with stronger light bulbs (1000 watts or more) and is a result of them being too close to your cannabis plant. Your stalks will turn red, purple, or pink and it’s a result of your plant building up a defense against the strong light. If you notice your leaves starting to burn and curl, simply move your light further away and it should fix it.

Sometimes when you do some low-stress training and some branches get more exposed to the light, it’ll cause this effect to happen. If your plant is otherwise healthy, this isn’t a cause for concern.

Fluctuating Temperatures

You’ll generally see some color changes in your cannabis plant when the temperature drops too low in your grow room. You can actually start to see some coloring in the cannabis leaves if the temperature drops too low during the night (or when your lights are off). This is actually a trick that some growers use at the end of the flowering cycle to get a splash of red, pink, orange, or even purple in their leaves and buds.

However, if you notice it after a period when your light is off, it’s time to check your grow room temperature to make sure it doesn’t dip too low.

Nutrient Deficiencies

Red stems could mean that you have a phosphorus or cal-mag deficiency. Nutrient issues are a little easier to spot because they will affect the leaves and the stem. This problem is common if your PH isn’t balanced because that creates a nutrient lockout, meaning your plant isn’t able to absorb the nutrients as the PH may be too acidic.

If you see yellowing in your leaves and your stems are turning red, it’s time to check your nutrient regimen to make sure you’re giving enough to your plants. Alternatively, using a slow-release formula will provide consistent low doses of nutrients so that your cannabis always has access to what it needs.

Final Thoughts

Once you start to understand that all your red stems can be identified relatively easily if you pay attention to what the rest of the plant is doing, it becomes easier to diagnose. Sometimes you’ll come across odd cannabis genetics that has red stems as a characteristic of that phenotype. If you find yourself scratching your head because all of your systems are dialed in and your plant looks healthy, just let it be.

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