Starting Cannabis Seeds

How to Keep a Cannabis Seedling from Bending Over

Stretching Seedlings

When cannabis seedlings break ground for the first time, growers have a hard time to keep the cannabis seedling from bending over once it gets taller. This can be caused by a few different issues that we will review in this article. 

This isn’t a hard issue to fix, however growers will need to understand what causes the cannabis seedlings to bend over as they grow.

Cannabis Seedling Stretching

Tender New Seedlings

Like with any new plant, cannabis seedlings are very tender and weak when they first germinate out of the growing medium. To break out of their shells and push up though the medium requires the seeds to use up all its energy in the seed itself. 

Once that energy is used up in the seed the new cannabis plant requires energy from the sun to grow.

How Cannabis Seeds get Started

Tender Cannabis Seedings
Cannabis Seedlings Bending Over

Once the cannabis seed is formed, and fall has arrived the cannabis seed will fall from the plant onto the ground below. Once the seed hits the ground anything can happen to that seed. If the seed is lucky it will make it through the winter on the ground. The seed waits for the perfect time to start its new growing process. This process starts when the ground is warm enough in the spring and the seed comes into contact with water. 

Once the seed has all these right conditions it will crack open its shell and start to push out a tap root that will go into the ground. The tap root will go down looking for more water, and nutrients it needs to keep growing above ground. Once the tap root is strong enough it will start to push the top of the seedling up and it will grow its first young leaves called cotyledons. These first leaves are what was contained in the seed itself.

Light Needs for Cannabis Seedlings

Seedlings don’t need as much light as flowering cannabis, however they can use the same amount of lighting that a vegetative cannabis plant. More light is generally better than less light for cannabis seedlings. Once the plant has left the ground it will need the right amount of light. You can think of light as the new nutrient that the seedlings need once the plant has pushed through the medium. 

Cannabis is a light loving plant, and remember that when seedlings sprout outdoors in the wild they are getting hit with the powerful light of the sun. They also like light in the blue range of the spectrum that is more like the sun in the spring growing season. 

You can read more on cannabis lighting here.

Cannabis Seedling Bending Over
Cannabis Seedling Reaching for Light

How Long Should the Lights be on for Cannabis Seedlings?

We recommend leaving lights on for seedling from 16 hours of lighting per day to 24 hours of lighting per day. Less than 16 hours of lighting per day can cause your seedling to keep stretching. The seedling will grow best when the amount of lighting matches what they would receive for lighting in nature.

Why is my cannabis seedling stretching so much?

So, the first issue that will need to be fixed to help the plant will be the excessive stretching once it comes out of the ground. This could be caused by a few different factors. We will review each below.

Seedling Too Close Together

A series of young cannabis plants with varying postures, highlighting the importance of proper care.

If the seeds were planted too close together they will be competing with each other for nutrientswater, and most importantly lighting. When this happens the both seedlings will compete against each other for these things, this will cause both seedlings to work against each other. 

They both are looking for energy to keep growing and not to get shaded out by the other plant next to them. This will cause both plants to grow as tall as they can looking to get ahead of the other one. Both plants will stretch, eventually the cannabis seedlings will both fall over.

Lighting is not Strong Enough

The next issue to address to keep your cannabis seedling from bending over is the lighting. Most growers do not use enough light over their seedlings or the light is too far from the tops of the seedlings. 

When the seedling is lacking enough, it “reaches” upwards looking for more light energy. If there is enough light, however it is too far from the top of the seedling, it must grow taller to get more light energy.  

Even if the grower is using some of their most powerful lighting, if it is located too far from the tops of the plants it will still be weak and cause the plants to stretch upwards looking to get closer. You should remember that seedlings only start with two small leaves to absorb light energy, so they will need a good supply of light to keep those two leaves healthy and growing.

Cannabis Seedling Reaching for the Light

Excessive Heat in the Growing Space

Another way to keep cannabis seedlings from bending over, is to keep the grow space cool and in the range that seedlings will grow best. If the grow space is getting over hot, above 86F (30C) its leaves will grow fast, and the stem will grow leggy causing the cannabis seedling to bend over, under the weight of its leaves. 

When starting seedling it is best to keep the temperature in the growing space at about 69F (21C) to 73F (23C) to prevent this from happening to your seedlings.

How do you strengthen Cannabis Seedling Stems?

Photo of a healthy cannabis seedling standing upright with a support stake beside it, indicating the preventive measure to stop it from bending

The first thing we recommend cannabis growers do not do, is to use anything to support the young seedlings. Doing so will in fact create a weaker seedling stem on the plant. If your seedling is already very leggy, it is best to just let it bendover. If you like you can also bend the seedling over in the opposite direction to help create a stronger stem. Just be careful, you don’t want to damage the seedling stem in any way. 

Using a gentle desk fan is another great way to strengthen seedling stems. This will create a gentle breeze over the young plants, lightly moving them back and forth. The bank and forth movement will tell the stem that it needs to grow stronger fibers keeping the cannabis seedling from bending over. You don’t want this fan blowing up a storm over your seedling, however a nice breeze will go a long way to stronger healthier plants.

Will Leggy Cannabis Seedlings Survive?

Leggy cannabis seedlings are not a death sentence for your young plants in any way. They will bend and fall over, however they will keep growing just fine. Over time the leggy seedling stems will grow stronger and start to stand on their own again. You can also use the tips above to minimize the stretching. 

The leggy seedling may be weaker however so keep a close eye on them. As they are in a bit weaker state, watch closely for “Damp off” this fungus will attack the young weaker seedlings. It will cause them to topple over and die. This can happen overnight.

Leggy Cannabis Seedling
Cannabis Seedling Standing Upright

Do Nutrients or Watering Techniques Play a Part in Seedlings Bending over?

Normally the seedling plant will have more than enough nutrients depending on the type of medium that they are growing in. Typically not having proper nutrients in the medium will actually slow cannabis growth, not allowing the seedling to stretch. Over or under watering can also do the same to the seedling. You can read more here about watering your cannabis properly.

Illustration of a close-up view of a cannabis seedling's base, showing a support mechanism like a tie or a small stake ensuring its upright growth


The one main contributor to keeping a cannabis seedling from bending over, is lighting. Keep your light close enough to your young plant, careful not to get them too hot. This is one of the main factors to keeping your cannabis plants from getting too leggy.

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