Safer Gardening and Legionnaires’ disease

Gardening is a popular pastime enjoyed by thousands of New Zealanders, helping people relax and escape the stresses of life. It provides enjoyment and exercise. The huge growth of interest in home-grown vegetables and fruit in recent years has added to people’s culinary enjoyment, and helped stretch their budgets further. Soil is rich with living organisms beneficial to plants which generally cause no harm to animals or people. Soil does however contain some organisms that can be harmful to people, if simple precautions are not taken. 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. This guide provides some simple and natural steps that all gardeners can take to reduce risk while continuing to enjoy their garden.


If people become infected with Legionella, they may get flu-like symptoms that can range from mild to severe. Those in good health may experience little more than mild flu-like symptoms. It is more common in older people, particularly if they smoke, have poor immunity or have a chronic illness. There has been no reported person-to person transmission of the bacteria.

Symptoms can include:

• Muscle aches

• Headache

• Tiredness

• Chills

• Shortness of breath

• Loss of appetite

• Coughing

• Stomach pain and diarrhea.

If left untreated, the disease can progress to Legionnaires’ disease, and require hospitalisation. The period between exposure and onset of illness for Legionnaire’s disease can vary between 2-14 days.

Reducing the Risk

As low as the incidence of Legionella contracted from gardening may be, it’s a serious issue and there are a few simple, easy and natural steps that all gardeners can take to reduce the risk while continuing to enjoy their garden. The Ministry of Health has an excellent publication “Safer and Healthier Gardening”. It provides guidelines to help reduce the risks for the home gardener which include:

• Water your garden and indoor plants using a gentle spray.

• Read the warning on bags of composted potting mixes.

• Wear gloves when handling soil, mulches, compost or potting mix.

• Wear a dust mask if handling potting mixes indoors or in windy conditions.

• Dampen potting mixes before use.

• Open bags of soil products or composted potting mixes slowly and away from the face.

• Make sure the working area (glasshouse, potting shed) is well ventilated.

• Wash hands thoroughly after gardening or handling soil products.

See your doctor immediately if you develop a flu-like illness that is worsening. Antibiotics are effective against legionellosis if given early. When working around bulk supplies of potting mix, avoid breathing dust or inhaling steam or mist. As a reminder, potting mix and compost packaging should contain a warning panel alerting gardeners of the risks.

Information courtesy of The Nursery and Garden Industry Association of New Zealand (NZGINZ)

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