Your Guide to...
Potting Soil Fires
Potting mixes unearthed
Potting soil poses such a fire risk because it contains a
high amount of inorganic material that may ignite easily.
Today’s potting mixes sold in garden stores contain
little or no actual soil. Instead, they contain a blend
of materials designed to absorb and retain water
and aerate the soil, such as:
When it comes to fire prevention, most people don’t
realize how much of a risk is posed by outdoor
potted plants.
Over the last several years, fire departments
throughout North America have reported a higher
than average number of fires – some serious –
caused by potting soil catching fire.
This new trend of accidental fires has two root causes:
1. Careless disposal of smoking materials
2. Spontaneous combustion
Today, smoking is only permitted outdoors where
there are often insufficient ashtrays or receptacles
for cigarette butts. Consequently, smokers often butt
out in any available container, such as a patio planter.
There are also anecdotal reports of fires where
potting soil has self-ignited. This can happen if a
plastic planter is left in direct sun, neglected and
allowed to completely dry out.
P sphagnum peat moss
P vermiculite
P perlite
P styrofoam pellets
P aged composted forest products
such as shredded wood or bark
P fertilizer
Spontaneous combustion
Many people tend to their planters in early spring
and may forget about them as the summer season
advances. If allowed to dry out, the potting
materials act as heat absorbers.
When combined with temperature build-up from
bacterial decomposition, the right mix of heat
and humidity and the presence of fertilizer, a fire
can start on its own – similar to what happens
to compost piles and hay bales. This is called
spontaneous combustion.
Fire departments state that the chance of this type
of spontaneous combustion in planters is relatively
low. However, if a potted plant is allowed to dry
out and something hot is placed in it, such as a lit
cigarette, it will burn.
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Helpful fire prevention tips
Consider following these helpful tips to help you prevent
losses due to a potting soil fire:
P Provide smokers with a designated smoking
area, and provide proper receptacles for
cigarette disposal.
potting soil as an ashtray.
P Maintain your planters, keep plants fresh and
watered and check them frequently in hot
sunny dry weather.
For further information on this topic, please contact your
independent insurance broker.
Visit www.avivacanada.com/riskmanagement for more
Your Guide to... information sheets on other loss control
topics.
P Discard any dead plants in planters.
P Don’t store bags of potting soil in direct
Readers should seek specific advice when dealing with
particular situations. Aviva Canada Inc. accepts no
responsibility for action taken as a result of information
contained in this publication.
P Avoid plastic planters; clay pots hold
The information in Your Guide to... is correct at the date
of going to press. Printed and published by Aviva Canada
Inc., Website: www.avivacanada.com
sunlight and near any combustible materials.
moisture better and will contain a fire.
P Avoid plastic planters if possible and opt for
clay ones, which will better contain a fire if
one occurs.
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are trademarks of Aviva plc and used under license by
Aviva Canada Inc. and its subsidiary companies.
A-5887 03/12
P Tell smokers not to use any pots containing
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