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How To Stop Hemp Seedlings From Stretching

The hemp seedling stage is one of the most challenging growth phases to master for many hemp farmers. Seedlings cannot yet handle the full strength of the sun; however, if they aren’t given adequate lighting, they may begin to stretch. Seedlings are extremely delicate, and if they stretch too much, their thin stems could snap, killing the plants. Knowing how to stop hemp seedlings from stretching is a valuable skill that every hemp farmer should have.

Don’t worry if your seedlings are stretching because it is possible to save them. But first, we will look at what causes stretching in hemp seedlings, how to prevent it from happening in the first place, and how to correct it once they have begun to stretch.

What Causes Stretching in Hemp Seedlings?

Several factors may cause stretching in hemp seedlings. Some factors that lead to stretching are biological, while others are environmental. Here are some of the reasons why hemp seedlings may stretch:

  • Inadequate lighting
  • High temperatures
  • Overfertilization
  • Plant genetics

How to Stop Hemp Seedlings from Stretching

If your seedlings are stretching, it is important to act quickly to resolve the issue. If they start to topple over, you’ll need to support them or risk the stems snapping. You can do this by embedding a small stick or piece of wire into the growing medium and tying the plant stem to it. In addition to providing support to the seedlings, you’ll need to identify the cause of the stretching and address it.

Inadequate Lighting

One of the most common reasons for stretching is weak lighting. The distance between your grow light and the plant canopy is a determining factor in how tall your plants will become.

If you keep your grow light far away from the canopy, the plants might not get enough light to sustain healthy growth. They’ll have to stretch in an attempt to seek the light. Conversely, the leaves may burn or curl if the light is too close.

The wattage of your light will largely determine how close you can place it above the plants. A 1,200W high-pressure sodium (HPS) light may need to be placed several feet above the canopy, while a 20W CFL bulb can be placed a few inches above the plants.

Whenever you change the distance or strength of your light, keep an eye on the plants to look for signs of stretching or burning, and make additional adjustments accordingly.

High Temperatures

Seedlings require a controlled environment to remain healthy, and temperature is one of the most critical environmental factors. The ideal temperature for hemp seedlings is between 70- and 80-degrees Fahrenheit.

If the growing area is too hot, this may stunt the growth of the leaves on the plants. If the leaves aren’t large enough, the plants won’t be able to absorb enough light, and they will stretch. In contrast, if the temperature is too cold, the stems tend to grow short and wide, and the overall growth is slowed.

It is vital to have adequate ventilation in the growing area so that the plants can stay cool under the warm grow light. Having a heater and air conditioner on hand is also a good idea to make it easy to regulate the temperature.

Improper Plant Spacing

Growing your hemp seeds closely together will lead to overcrowding. As your hemp plants mature, their leaves will start overlapping with the adjacent plants, preventing them from receiving enough light. As a result, the plants will begin to stretch in an attempt to rise above the dense canopy.

Spacing the seedlings apart will allow for optimal light penetration, thus helping to prevent stretching.


If you’re using synthetic nutrients, you may be overfertilizing your young hemp seedlings. These salt-based fertilizers may cause seedlings to grow too rapidly and become less robust, making them more prone to diseases.

If this is the case, try switching to a weaker fertilizer with lower NPK levels or reducing your use of synthetic nutrients altogether. You should not apply hemp fertilizers until seedlings develop their first pair of true leaves.

How To Stop Hemp Seedlings From Stretching: Conclusion

One of the most important factors in growing healthy seedlings is to start with high-quality seeds with strong genetics; however, it also is essential to cultivate them in a stable environment. By providing adequate lighting and nutrition, regulating the temperature in the grow room, and spacing the plants appropriately, you can prevent your hemp seedlings from stretching and becoming weak.

Contact Fortuna Hemp for more information about growing healthy hemp seedlings. While you’re here, check out our collection of high-quality feminized CBD hemp seeds.

What are your tips for preventing stretching in hemp seedlings? Please share your advice in the comment section below.

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