Why is My Weed Plant Growing Tall and Skinny?

If it’s your first time growing cannabis you might be surprised and disturbed to notice that your plants are growing tall and lanky. Having started with some potent Indica strain you had probably envisioned having some thick stems bending down to the weight of the nugs. What you got instead were tall skinny plants that look barren. What causes weed to grow tall and lanky and what can you do to prevent this from happening?

Why Does Weed Grow Tall and Skinny?

cannabis growing tall and skinny
Cannabis growing in the open air

As a new grower, you may be very frustrated to see how the cannabis crop pales in comparison to the bushy-looking plants that you had in mind when you ventured out. Several factors may contribute to your cannabis plants growing very tall and thin at the same time. Here are some common ones to be on the lookout for:


Tall and lanky plants may have nothing to do with your cultivation prowess. It may all be in the genetics of the strain that you started with. To prevent this ensure that you do a thorough background search on the growth characteristics of the strain.

Prolonged Vegetative Stage

Keeping your plants in the vegetative stage longer than necessary will result in tall and thin plants. Once your plants are ready to move to the flowering stage make sure that you create the necessary conditions to switch the plants.

Distant Lights

When the grow lights are too high, the plants will stretch to reach them. It may take some experimentation to get the right distance between the plants and the light.

Weak Light Source

Similar to a faraway light source, plants will also overstretch when placed in weak light, hoping to find some more light. This commonly occurs when fluorescent bulbs are used because they are weaker than LED and HID lights.

Poor Light Distribution

When light is not evenly distributed in your grow room the plants that are not getting sufficient light will grow tall and skinny.

Why Should You Prevent Tall and Skinny Plants?

tall and skinny cannabis plant
The tall and skinny cannabis plant

Once you notice that your plants are growing tall and skinny you need to find ways to reverse the situation before it’s too late. Allowing this situation to go on will cause the following challenges:

  • A weak stem will not be able to support buds once they develop
  • Tall and thin plants are likely to have an uneven distribution of nutrients and hence suffer from nutritional deficiencies
  • The plants may outgrow the height of the grow room space and this will affect many things including light and air circulation. This will affect the general health of the plants
  • When the plants grow too tall they may experience light burn resulting in an inferior harvest

How to Prevent Weed From Growing Tall and Skinny

Why is my weed plant growing tall and skinny
Young woman in a hemp field checking plants and flowers.

Considering all the dangers of allowing your plants to grow tall and skinny, is there something that can be done to prevent this from happening?

Fortunately, several techniques can be employed to prevent cannabis plants from taking that route. Here are a few to get you started:

Start with the right genetics

Genetics plays a key role in the growth characteristics of your crop. Therefore ensure that you choose strains with the right genetics and can do well in your environment.

Low-Stress Training (LST)

This technique can be used to prevent cannabis plants from growing too tall. The plants are bent to force them to grow horizontally. This should be done gently to avoid breaking the fragile stems. If done properly, the plants will become bushy in a short while.

Don’t prolong the vegetative stage

Once you have found the right strain, find out how long the plants should stay in the vegetative stage and use that as a pointer. Also, find out the signs that you should look out for to know that the plants are ready to switch to the flowering stage.

Keep lights at the right distance

Once you select the kind of bulbs that you want to use, find out how far they should be away from the plants at each stage of growth. Also, ensure that you choose the right lights for this operation. Dim lights will cause your plants to grow tall and skinny.

Ensure that your grow room has adequate space

Your cultivation room needs to be large enough to allow you to space your plants adequately to prevent them from competing for resources. This will reduce the chance of your plants stretching too much for resources.

Prune tall plants

If you notice that your plants are growing too tall, it is okay to prune off the excess foliage. This will encourage the plants to grow horizontally and become bushy instead of tall and lanky. Pruning and trimming are always good for a plant’s health.

Use reflectors in your grow room

Reflectors on the walls of your grow room do a great job of distributing the light evenly. This will prevent the plants from growing tall to compete for vertical light.


SCROG technique involves the use of nets to limit the vertical growth of your plants. It also ensures that each branch gets a sufficient amount of light and that the canopy grows bushy.

Tips to Becoming a Pro Weed Grower

Your plants growing tall and skinny is not a good sign. Fortunately, a couple of things can be done to prevent this from happening. This includes starting with the right genetics, ensuring that the lighting is adequate, and using techniques such as LST and SCROG.

As a final note, here are some tips to help you become a master grower:

  1. Before you start, learn as much as you can
  2. Ensure that you maintain the grow room under optimum conditions
  3. Closely monitor the plants for any signs of danger
  4. Never rely on experience

FAQ: Weed Plant Growing Tall and Skinny

What causes a weed plant to grow tall and skinny?

Answer: Too much nitrogen in the soil and too much light can cause a weed plant to become tall and skinny. Other environmental factors such as temperature and humidity can also lead to this problem.

How can I prevent my weed plant from becoming tall and skinny?

Answer: To prevent a weed plant from becoming tall and skinny, make sure you provide it with the correct amount of nitrogen and light. Additionally, keep the temperature and humidity levels in the optimal range for the species of weed you are growing.

What should I do if my weed plant is already tall and skinny?

Answer: If your weed plant is already tall and skinny, prune it back to help promote bushier growth. Reduce the amount of light and nitrogen that the plant is receiving and increase the water and fertilizer levels. Additionally, monitor and adjust the temperature and humidity levels as needed.

Final Note

Overall, tall and skinny weed plants are caused by many environmental factors, such as light, temperature, and nutrients. As a grower, it’s important to carefully monitor these variables to ensure your plants will stay healthy and produce the best quality of buds. With the proper adjustments, you can help your plants achieve the desired shape and size.

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