Do cigarette ashes kill house plants?

Answer 1

It can.

There are several risks:

1. cigarettes are often treated with a variety of chemicals. Most of these chemicals are toxic to plants. If the cigarettes were 100% natural than the ash by itself would not be an immediate threat (nicotine by itself for example is harmless to plants and can actually be beneficial in some ways, including as a natural pesticide)

2. Ash of any kind is highly alkaline. While small amounts of alkaline substances will not harm a plant it is important to check the overall PH balance of soil and tune it to the plants needs (some prefer acids, some alkaline, some require neutral). Too much ash will push most plants to too high an alkaline level which cuts off their nutrient supply and kills them.

3. The biggest risk to plants from cigarettes is tobacco mosaic virus (TMV). Even in its dried and packaged form, tobacco can transmit TMV. This virus infects 150 different plant species, can live up to 50 years in a dry plant and can be transmitted from the hands of a smoker to the plants he is working with.

There is no control except removing the infected plants as completely as possible to avoid spread. TMV stunts the plant and damages the fruit, eventually killing it (often quickly).

While the burning of the tobacco may kill TMV inside the heated portion, it is still possible to conduct TMV from the unburned portion of tobacco onto the colder portion of ash as its falling from the cigarette. TMV is death to most plants, above and beyond any other chemical additives that may be present in most manufactured cigarettes.

So in summary if you wish to use nicotine to treat plants, get it in its pure form, already extracted. Keep tobacco and its ashes away from other plants, and wash your hands thoroughly before touching a plant if you have had any contact with a cigarette.

Answer 2

Short answer: not usually

Long answer:

It can.

Things to consider:

1. If the material is natural (preferably organic) than there should be no immediate detrimental effect. If the incense includes unnatural scented chemicals, it could act as a poison for some types of plants.

2. Ash (of any kind) is often highly alkaline. Some plants prefer acidic soil, some plants prefer neutral soil. It is important to know the types of plants you have and the types of soil they prefer.

The amount of ash added should be kept to a minimum unless you know how to properly balance the PH of your soil / compost to best suit the environment your plants prefer.

Though its really not hard to balance the PH needs of your plants and its often a process you need to follow anyway if you are using tap water (since tap water can vary wildly from highly alkaline to highly acidic depending on environmental factors).

So basically, make sure you are using natural ash, not chemical incense and be aware that PH balance matters no matter what you are adding to a plant, whether its water, ash or otherwise, ash just simply happens to fall in the alkaline side of things you might be adding.