Weed burning using a torch

Weed Burning 101


Rune Heick



Heibjerg Blog


Weed burning, flame weeding, or torching weeds. Many names, same concept. Using a flame to damage the weeds cells. This is an extremely efficient way of removing weeds from patios or driveways. The goal is to slightly burn the weed for 1-5 seconds. This will cause the weed to deplete all its energy and whither away in a few weeks.

Weed burning principals

Using a weed burner is a relatively easy way of removing weeds. Even though it looks like a small flamethrower a weed burner is quite safe if used properly. The operation is quite simple.

  1. Hold the burner over the weed to kill. (Do not ignite it)
  2. Hold it for 1-5 seconds.
  3. Move on to the next weed.

After using the weed burner the area is still full of weeds. The goal is not to burn away the weeds. This might seem a bit discouraging. But after a few days, the weeds have withered away.

Why not burn away the weeds completely? This is because this will keep the root intact and it will just sprout out new leaves. Then we are back to square one.

How does a weed burner work

Weed burner torches are designed to damage the cells in the plant. It does so using thermal shock to the plant. This causes the cells in the weeds to burst.

Normally Water has a long way to travel from the roots to the leaves. How does it do that? Plant stems have some very special cells called xylem. These cells form long thin tubes that run from the roots up the stems to the leaves. This process is called capillary action. As water evaporates from the leaves it helps pull up new water from the roots. All the weed needs are transported throughout the plant using this system.

When the cell bursts it is damaging the xylem. This disrupts the water flow in the plant. This stops the roots from taking in new nutrients and water. The weed will still evaporate water causing the plant to wither away. Soon the root will have depleted all its energy and dies.

Burning away the weeds completely

The problem is that this causes the roots to use their energy to sprout out new stems and leaves. This will "restart" the weed. In theory, if you continued to burn away the weed completely every time it sprout you could also deplete the root's energy. But this would be a much more time and energy-consuming method. It is better to turn time into a weapon by just passing the weed briefly with the burner.

Is a weed burner better than poison

Better is a hard definition. It is for sure more environmentally friendly as no poisons or harsh chemicals can contaminate your soil and groundwater. Weed burning is extremely efficient. The same can be said for poison but I try to avoid it personally. I will of course say that one should use a Heibjerg Robot instead.


Where to use a weed burner

A classic weed burner should not be used too close to combustible materials such as wood or plastic. They can be around 600°C at the opening, so they can ignite stuff if not careful. They also work as well on plants as they do on weeds. So do not use them too close to plants you like. The burner does not know the difference.

However, they are perfect for gravel or stone-paved areas. Typically they are used on patios and driveways. The method is extremely efficient on smaller weeds. Larger weeds might need a couple of treatments.

How often should I use a weed burner

Use the weed burner once every two to three weeks or as needed while the weeds are growing. Burning kills annual weeds completely but does not completely eradicate the roots of more established weeds. With multiple treatments it will eventually deplete the weed's stored root energy, killing the weed completely.

Why not use a robot

The heibjerg robot is designed to automate weed burning. It does so safely and efficiently.

Like a robotic lawnmower, but for weed burning.
It is a great alternative to the classic weed burner. But more importantly, it can save you hours of weed burning throughout the season. Hours that can be spent more productively in the garden, or simply enjoying the summer.

Check out Heibjerg at: https://www.heibjerg.com

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