Hot water weed control

Using hot water to combat weeds is nothing new. The first patent was taken out back in the 1880s, but the method could not be used on a large scale owing to the inadequacies of the technology.

Thermal weed control is based on transferring energy (heat) to the plant. Water is one of nature's best energy carriers and often easily available. Heatweed introduced the hot-water method in Scandinavia and it is proven to be the safest and best solution.


Steam and hot air do not work in the same way as hot water at all:

  1. Water is one of nature’s best energy transmitters and hot air is one of the worst.
  2. Gravity means that the water flows downwards and reaches the plant quickly, right down to the roots.
  3. Hot air and steam always rise , so some of the energy (heat) disappears before it gets to the plant.


The Heatweed Method fully exploits the properties of water: Combined with sensor technology and advanced temperature control, this results in a means of controlling weeds that requires very little energy. Thanks to efficient energy transfer, a maximum of four applications a year will suffice.

A study carried out at the University of Copenhagen shows that treatment with hot water produces the lowest weed cover – even with the lowest treatment frequency. See the below table:


The temperature of the water applied to the plant has to be 98-99°C for the plant to die. Otherwise there is no systemic effect on the roots and the plant grows back after you have ‘watered it’.

  1. Uneven temperature = uneven weeding results: A high-pressure washer is designed for high pressure – not for a stable, high temperature. The temperature of the water from high-pressure washers varies by at least 10°C, especially above 75°C. Heatweed machines have been specially developed for professional weed control and work in completely the opposite way – at a very low, stable pressure all the time.
  2. Lower energy consumption and higher capacity = lower costs and higher user satisfaction: Higher energy consumption and lower efficiency mean higher labour and operating costs, while 3-5 times more water per square metre means 3-5 times higher costs.


The Heatweed Method = the weeds disappear – and stay away with minimal water consumption and stable temperature control (max. +/- 0.6°C). The object is not to wash the weeds away or water them, but to remove them for good.