DANGER - Legionella season is here

Legionella and legionellosis

When your staff and customers handle garden soils, compost and potting mixes there is a potential risk of contracting legionellosis, or Legionnaires’ Disease.

Legionellosis is a respiratory (lung) infection, caused by the Legionella longbeachae bacteria. The severity of legionellosis can range from a relatively mild respiratory non-pneumonic illness (Pontiac fever) to pneumonia (Legionnaires’ disease) which if left untreated may be fatal.

Not all those who come into contact with the bacteria become sick and symptoms will vary from person to person. If people become infected with Legionella, they may get flu-like symptoms that can range from mild to severe. It can, however, be life-threatening to people who have health factors that increase their susceptibility. Those most at risk include smokers, the elderly and those with existing respiratory illnesses and weakened immune systems.

Soil may be rich with living organisms beneficial to plants which generally cause no harm to animals or people. It does, however, also contain some organisms that are not beneficial.

A type of Legionella bacteria, which is commonly found in the environment, is one of these. It has been shown to cause Legionnaires disease in a few people and on rare occasions it can be inhaled in water vapour and in the dust associated with soil and potting mix.

NGINA endorses the NSW Health information on ways to help in the prevention of contracting Legionella longbeachae. Reduce exposure to potting mix dust by following the manufacturers' warning present on potting mix labels, including:

  • Wet down the potting mix to reduce the dust.
  • Wear gloves and a P2 mask when using potting mix.
  • Wash your hands after handling potting mix or soil, and before eating, drinking or smoking.


In addition it is worth advising gardeners to:

  • Minimise the amount of dust when working in the garden
  • Water gardens and indoor plants using a gentle spray
  • Read the warning label on bagged composts or potting mix
  • Wear gloves
  • Wear a dust mask so that any dust is filtered out before you can breathe it in
  • Dampen potting mixes before use
  • Open bags of soil products slowly, away from the face
  • Make sure the working area (glasshouse, potting shed) is well ventilated
  • See a doctor if you develop a flu-like illness which is worsening and
  • Wash hands thoroughly after gardening or handling soil products.


Michael Danelon, CNP Specialist
Nursery Industry Development Officer (NIDO)