Never put out a cigarette in a flower container, pot or basket, or in black earth, mulch or any other similar materials. These materials are composed of peat, moss and combustible chips, and they also contain chemical fertilizers. All constitute potential sources of fire when they come into contact with a heat source. A period of up to four or five hours may elapse between the time that a cigarette is crushed and the appearance of the first flame.
When extinguishing a cigarette outdoors, we highly recommend that you use an ashtray suited to outdoor risks, such as wind. At home, use a tin with good depth filled with damp sand, and place the tin on a fire-resistant surface.