How to disinfect a tunnel or greenhouse with sulfur?
Sulfur is mixed with a potassium compound such as saltpeter. Then, this mixture is sprinkled on metal trays and placed in the tunnel. Starting with the furthest tray, the sulfur is ignited.

All safety precautions must be observed.

15 grams of sulfur per cubic meter of space is sufficient.
Disinfection with sulfur is best done at a temperature of at least 10 degrees Celsius, but it is better if it is warmer.

Before starting the disinfection, the tunnel or greenhouse should:
- be cleaned
- the structure should be inspected and repaired if necessary
- be washed - preferably with potassium soap
- old flowerpots should be removed
- the soil should be thoroughly watered, but also the plastic or glass should be moistened with water.

What comes after disinfection?
First, the space needs to be ventilated, which will take several days for the tunnel to cool down.

Sulfur has acidifying properties, so lime must be applied to bring the soil back to the desired pH level. Soil preparation for sowing should only be done once it is certain that all gas has escaped from the interior.