Though gardening has been called good for the soul, using contaminated potting soil may be bad for your health. Because potting soil is a mix of materials, usually peat or wood-based, it can grow bacteria and fungi, especially when stored in warm and moist environments. Infected potting soil has been linked to several diseases including Legionnaires’ disease, a bacterial pneumonia that has been making headlines this summer.
The recent Legionnaires' disease outbreak has many people concerned about this rare illness caused by bacteria in your water or potting soil. We spoke with Dr. Francesca Polverino, a physician scientist and tenured Lester and Sue Smith professor of medicine at the Baylor College of Medicine, about what gardening enthusiasts should know when planting their favorite flowers or crops this year.
How Can Potting Mix Make Me Sick?
Though it is uncommon, infected potting mix can cause illness. Anyone who inhales dry or dusty soil that contains bacteria or fungi is at risk of contracting many different airborne diseases, though certain people are at higher risk. “Breathing in this dust may cause lung infections in some people, particularly older adults, people with weakened immune systems, people who smoke or those with chronic lung disease,” Dr. Polverino explains.
The best-known infection linked to potting soil is Legionnaires' disease, a type of pneumonia caused by Legionella bacteria. However, the risk of getting Legionnaires' disease from potting mix is low, with most cases (like the current ones in the news) caused by breathing in tiny droplets of contaminated water from sources like AC units, hot tubs, decorative fountains or humidifiers.
But Legionnaires is not the only disease linked to infected soil. In some parts of the U.S., usually central and eastern states, fungi called Histoplasma capsulatum can cause a lung disease called Histoplasmosis. Another fungi occasionally found in potting soil, called Aspergillus, can cause illness in people with lung disease, a specific immune sensitivity to aspergillus or a weakened immune system.
What Symptoms Should I Look Out For?
Most people who contact one of the previously mentioned diseases will begin developing symptoms two to 10 days after exposure. For Legionnaires’ disease, symptoms include fever, chills, cough, shortness of breath, muscle aches, headache and fatigue. Rarely, patients may experience nausea, vomiting or diarrhea. Similarly, aspergillosis symptoms are similar to asthma and include coughing, wheezing and shortness of breath. While histoplasmosis causes mild flu-like symptoms, that appear between three and 17 days after exposure to the fungus.
Dr. Polverino suggests paying close attention to severe shortness of breath, chest pain, confusion or a high fever. “These infections are rare, and most people who garden never become sick,” Dr. Poliverino said. “However, anyone who develops these symptoms after handling potting mix, especially patients who are high-risk, should contact their primary care doctor immediately.”
Staying Safe while Handling Potting Soil
Unfortunately, it is impossible to tell by looking, smelling or touching whether potting mix or water contains bacteria. “Contaminated products usually look and smell normal. That's why it's important to follow safe gardening practices every time you use potting mix,” she said. You can reduce your risk by following a few simple precautions:
- Open bags of potting mix slowly and away from your face to avoid breathing in dust from potting mix.
- Lightly dampen dry potting mix before using it to reduce dust.
- Wear gloves while gardening, and possibly a mask (such as an N95) if you are at higher risk or working with large amounts of dry potting mix.
- Wash your hands thoroughly after gardening and before eating or touching your face.
- Store potting mix in a cool, dry place and keep the bag sealed.
Overall, millions of people who garden will never contact a disease from the soil, but being prepared is the best way to enjoy this wonderful hobby without worry. For more information about Legionnaires’ disease or diseases you can get from soil, visit our website.
Blog last updated: July 22, 2026
