Spring is the busiest time of year in most Perth gardens. Pots get refreshed, beds get topped up and new seedlings go in. It is also the season when WA Health reminds gardeners about a less obvious risk in the bag of potting mix. A few simple habits make that risk much smaller.
The concern is a bacterium called Legionella longbeachae. It lives in potting mix, compost, mulch and garden soil. Breathing in dust or fine droplets from these products can lead to a serious lung infection. The good news is that the steps to protect yourself are cheap and quick.
What Legionnaires’ disease is
Legionnaires’ disease is a serious pneumonia caused by Legionella bacteria. WA Health explains that the longbeachae species is the one found in garden products. A different species, Legionella pneumophila, is linked to water systems such as cooling towers and spas. For home gardeners, bagged and bulk soil products are the main thing to think about.
People are thought to become infected by breathing in contaminated dust or tiny water droplets. WA Health also notes that hand to mouth spread may play a part. The bacteria can stay on hands that have handled potting mix or other garden soils. That is why washing up after gardening matters as much as wearing a mask.
Why spring is the time to take care
In a spring warning about Legionnaires’ disease released in August 2026, WA Health said notifications linked to potting mix and garden soil usually rise in spring. That is when people plant, mulch and garden more. Over the past three years there were 82 notifications of disease caused by Legionella longbeachae in WA. Of those people, 42 needed hospital treatment and two died.
Those figures are not a reason to stop gardening. They are a reason to treat potting mix with a little more respect. Most of the protection comes from a handful of habits that take seconds. Once they become routine, you will barely notice them.
Which garden products carry the risk
WA Health lists potting mixes, gardening soils, mulches, composts and soil conditioners in its advice on Legionella and garden soils. Cases in WA have been traced to commercial products, including packaged potting mix and bulk soil supplies. The department also says soil in the natural environment may still pose a risk. In short, any dusty soil product deserves the same care.
There is currently no strategy that can control or remove the bacteria from commercial garden soils. That means the safety steps sit with the person using the product. Health warnings are printed on bagged materials. Signage is also provided near bulk products at suppliers.
Simple steps for safer potting
The precautions from WA Health are easy to fold into a normal gardening session. Keep a box of gloves and masks with your potting gear so they are always at hand. Here is what the department recommends.
- Wear gloves and a well fitting disposable face mask.
- Open bags with scissors rather than tearing them.
- Dampen the potting mix before use to cut down dust.
- Avoid breathing in dust and fine spray from the mix.
- Wash your hands thoroughly after gardening and before taking off your mask.
- Store potting mix in a cool, dry place out of direct sunlight.
Opening the bag is often the dustiest moment. Cutting it slowly with scissors keeps the puff of dust away from your face. Adding a little water to the top of the bag before you scoop also helps. The aim of each step is the same, which is to keep dust and droplets away from your nose and mouth.
Potting on a deck, patio or balcony
Pots are a handy way to garden when space is tight. They suit decks, patios, courtyards and balconies. With a deck or pavers, the choice of paving vs decking for a Perth outdoor area can shape where you set up a potting station. A spot with room to work and a hose nearby makes dampening the mix simple.
Shade helps on hot days too. A covered corner keeps you cooler while you work and gives your bags a place out of direct sunlight. A look at the best Perth suburbs for outdoor living with shade sails shows how shade changes the way an outdoor area gets used. The same shaded spot can double as your potting bench.
Think about water as well. Damp mix is less dusty, so a tap close to your potting area is handy. If you are planning new garden taps or other outdoor plumbing, it is worth reading about eco friendly plumbing before you start. Good planning means less dragging of hoses around the yard.
Gardening through a Perth summer
Perth summers are long, hot and dry. Plants in pots need regular watering through the warmer months, and the mix in an open bag can dry out between uses. Store your bags the way WA Health suggests, in a cool, dry place out of the sun. Reading about how Perth’s climate shapes smart landscape design can help you choose pots, positions and plants that cope with the heat.
Who is most at risk
Anyone can be infected, according to WA Health. Older people, smokers and people with weakened immune systems are at greater risk. If you fall into one of those groups, the precautions are even more worthwhile. Take your time and do not skip the mask or gloves.
Know the symptoms
Symptoms can appear up to 10 days after exposure. WA Health says they often look like severe influenza. They may include fever, chills, muscle aches, headache, dry cough, tiredness, loss of appetite and shortness of breath. If you feel unwell after gardening, see a doctor promptly and mention your recent contact with potting mix or soil.
The department says early diagnosis and antibiotic treatment can significantly improve outcomes. That is why telling your doctor about your gardening is so useful. It gives them a clue they might otherwise miss. Do not wait for symptoms to pass on their own if you are getting worse.
Frequently asked questions
Is compost from my own bin a risk?
WA Health includes composts in its list of garden soils that can carry the bacteria. It also says soil in the natural environment may pose a risk. So the same gloves, mask and hand washing habits apply to homemade compost. It is a simple rule to follow for any soil product.
Does wetting the potting mix help?
Yes. WA Health recommends dampening potting mix before use to reduce dust. Less dust means less chance of breathing in the bacteria. A watering can or a gentle spray from the hose does the job.
What kind of mask should I wear?
WA Health suggests a well fitting disposable face mask. A good fit leaves fewer gaps around the edges. Keep it on until you have washed your hands. That stops you touching your face with soil on your fingers.
Are bagged products labelled?
Yes. WA Health says health warnings are published on bagged materials. Signage is provided near bulk products too. Take a moment to read the label before you open a new bag.
This article is general information only and is not medical advice. If you have symptoms or concerns about your health, speak with a doctor or qualified health professional.
