Root cause

Thanks to Eco Weedkiller technology, the water remains hot until it reaches the root and destroys it. In other words, our devices transfer enough thermal energy to the plant’s roots to destroy them. The water dispensed by our machines is always 100 °C when treating areas covered by weeds or invasive species. In addition, the large droplet size ensures that enough thermal energy is bound to the water to destroy the roots effectively. The amount of water used determines how deep the heat penetrates. A good result is typically achieved with 3–5 litres of water per square meter. Deep-rooted weeds, woody plants, or invasive species require large amounts of water.

Boiling water is an unfamiliar threat to plants, against which they have not developed any protection. Many plants do, however, have a natural ability to survive events such as wildfires. Burning the soil destroys the above-ground parts, but most organisms, roots, and seeds survive, and growth soon continues. When Eco Weedkiller devices apply hot water directly to the plant and its roots, the sudden thermal energy destroys their cell structure. Hot water is an effective, ecological, and cost-efficient method to eliminate roots, unlike, for example, digging, which is costly and increases the risk of harmful plant species spreading.

Steam is lighter than air, so it tends to rise upwards and cannot reach the roots. Water turns into steam when it exceeds 100 °C, which makes steam very hot — but only under pressure. When steam exits the nozzle of a pressurized device, it immediately begins to condense back into liquid and therefore quickly releases its heat into the surrounding air. In addition, water transfers heat much more effectively than steam, because its stored heat — or heat capacity — is high (4.18 kJ/kg/K). For example, one litre of 100 °C water (at 1 bar) stores the same amount of heat as about 3.34 cubic meters (m³) of steam.

Although the plant and its root are destroyed, new seeds inevitably find their way into the soil. That’s why it is advisable to repeat the treatment during the growing season. A general recommendation is 2–4 treatments, depending on how good results you want to achieve.