Are Cigarette Ashes OK for Houseplants?


Picture of an ashtray with partially smoked cigarettes in it on a wooden deck

If you’ve already read a few of the articles I’ve written regarding plant food, fertilizer etc.. you’ve probably discovered that you can nourish your houseplants with more ingredients than you were aware (such as manure or human urine), but what about cigarette ashes? Would your houseplant benefit from cigarette ashes or not? Admittedly, I had to do quite a bit of research to answer this common question.

Are cigarette ashes OK for houseplants? Cigarette ashes can be okay for some houseplants, but with their low nutrient content (up to one percent of potassium), there are better sources of plant food out there. If you or someone who smoked didn’t burn through the cigarette all the way, then the nicotine can prove dangerous to your houseplants as it does to us people. Also, there’s the matter that tobacco may lead to the development of tobacco mosaic virus, which can be very detrimental to the health of your houseplants.

Curious what tobacco mosaic virus is? Then you’re going to want to keep reading. In this article, we’ll tell you once and for all if you should use cigarette ashes in your houseplant soil. We’ll also talk about if any other type of ash is better and how to avoid tobacco mosaic virus for your houseplants.

Let’s begin!

Cigarette Ashes for Houseplants: Yes or No?

The school of thought of whether it’s appropriate to use cigarette ashes on houseplants is decidedly mixed. There’s this article from UK publication Independent that mentions it’s fine to use cigarette ash on indoor plants if it’s burnt through. That’s the only way to ensure you’re not feeding your houseplants nicotine.

Why cigarette ash in the first place? Well, it contains some potassium, although admittedly not as much as many other sources of natural fertilizer. Some gardening experts believe the ash may only have a single percent of potassium. That’s not enough for your houseplant to really live off for the long-term. The ash could contain calcium, but regarding quantities, no one’s quite sure.  

Sometimes, ashes from cigarettes can contain more unwanted ingredients than helpful ones. For instance, there’s the risk of nicotine in the ash, as we said in the intro. Also, heavy metals and soot may transfer to the ash as well, the latter of which can be poisonous for most houseplants.

Nightshade plants can be especially sensitive to the effects of cigarette ash if fed it as a fertilizer. Also known as the Solanaceae family, nightshades include ornamentals, weeds, spices, medicinal plants, agricultural crops, trees, shrubs, epiphytes, lianas, vines, and both perennial and annual herbs.

While many of the houseplants in this family are poisonous themselves, others are vegetables and fruits you may consume regularly. Yes, chili peppers, bell peppers, eggplants, potatoes, and tomatoes are all technically nightshades. They belong to a family with roughly 2,700 different species and nearly 100 genera.

Okay, so nightshade plants should not be fed cigarette ashes as fertilizer, but what about the rest of your indoor plants? As we said before, the nutrients the plant gets from cigarette ashes are very low, thus making the benefits of using this ash incredibly negligible.

Could you use it as a source of plant food? Sure. Whether it’s a great idea though is debatable.  If your indoor plant is starving that much for potassium, you can give it plenty of other homemade fertilizers to maintain nutrient levels. For instance, try banana peels. Not only do these contain potassium, but, during their decomposition, banana peels will release magnesium, phosphorus, and nitrogen. This isn’t in huge amounts, mind you, but banana peels already contain more nutrients than cigarette ashes with less risk to your houseplant.

There’s also the matter of tobacco mosaic virus and what it can do to your houseplants.

Understanding Tobacco Mosaic Virus

What Is Tobacco Mosaic Virus?

Okay, so we’ve mentioned tobacco mosaic virus enough, but what actually is it? Tobacco mosaic virus was first identified by a man named Martinus Beijerinck back in 1889. He called it tobacco mosaic disease then, but it’s referring to the same virus.

Tobacco mosaic virus doesn’t necessarily kill the affected houseplant, but it will make the leaves turn unpleasant colors and lead to mottling that looks almost like a mosaic pattern. Solanaceae family members, such as those nightshades we discussed in the last section, are a lot more likely to suffer serious effects of this virus than other houseplants.

Causes

How does a houseplant get tobacco mosaic virus in the first place? Some people believe that if you’re a smoker and an indoor gardener (or an outdoor gardener for that matter) that you can spread it that way. That’s not entirely true. Breathing cigarette smoke on your houseplants is not the greatest thing for them, but you can’t infect them like this.

That said, if you have a lot of tobacco on your hands and then you touch your houseplant, that could cause the virus to spread. This is even more likely to happen if you smoke rolled cigarettes you made yourself.

The tobacco in cigarettes, including air-cured tobacco, could have traces of the virus. That means anytime you feed your houseplant cigarette ash, there’s a chance they could end up with tobacco mosaic virus.

Spreading the Virus

The troublesome part of tobacco mosaic virus is it’s especially hardy. If your houseplant were to die, the virus could still live on. Even if you exposed your plant to very high temps, the virus probably will survive. It’ll remain in the soil and even crop debris. If you plant a new indoor plant where the old one was, you could unwillingly infect it with tobacco mosaic virus.

What’s worse is you can spread the virus long after getting tobacco on your clothes or gardening equipment. On items like clothing, containers, greenhouse benches, stakes, trellis wires, and gardening tools, tobacco mosaic virus will live on for months.

When your houseplant gets the virus, it could develop into the seed coat. This will typically only happen if you have a young infected houseplant or a young houseplant with a virus-ridden mother plant. Now, after germination, the houseplant produces ribonucleic acid or RNA that’s infected by the virus. Its proteins have traces of the virus that travel to the plasmodesmata or cell walls, then to the houseplant’s phloem and xylem, aka its translocation system. In short, the whole plant gets the virus and could die.

Symptoms

We already talked about the trademark appearance of an indoor plant infected with tobacco mosaic virus. The leaves will curl (thanks to the plant tissue yellowing) and the leaves will develop spotty patches that look like a mosaic.

If it’s a tomato plant that has the virus, you may notice slowed ripening, fruit that harvests in a variety of colors, and/or misshapen fruit. Other houseplants could not grow to their full potential thanks to the virus.

If you believe your houseplant has tobacco mosaic virus, it could be upwards of 10 days before symptoms manifest. Keep your eyes peeled.

Can Other Types of Ash Benefit Your Houseplant?

After reading to this point, you’re thinking it’s best to steer clear of any and all ash for your houseplant. Is that the right way to go? Not necessarily. There’s no need to write off all ash just because cigarette ash can be detrimental to your houseplant.

There’s another type of ash known as wood ash that your indoor plants quite like. While short on supply of nitrogen, wood ash does contain phosphorous, calcium, and potassium. That said, if your houseplants prefer a soil acidity of at least 6.5 pH, then you probably don’t want to use wood ash.

If it turns out the ash is safe for your houseplants, then cover a bit of the soil with the ash, about 1/4 inches. Use a cultivator or hand rake to push the ash into the soil, but leave the roots and plant base alone.

Make sure you keep checking the pH, especially several weeks after adding the wood ash, as you don’t want the pH getting too high.

You can also try the following types of ash for your houseplants:

  • Plant ash, which can keep moths and flies from depositing their eggs in your houseplant’s stems.
  • Rice hull ash, which will ward off turnip moths, slugs, snails, and cutworms. You want to dig a trench around your houseplants and then add your ash.
  • Corncob ash, which ants don’t like. If growing bean plants especially, surround the base with this ash.

Related Questions

How do you treat tobacco mosaic virus?

If your houseplant has tobacco mosaic virus, you don’t have to stand idly by and watch it suffer. Try doing the following as soon as you can:

  • If you handle tobacco or tobacco products often, make sure you use the right disinfectant. Your options include non-fat milk powder with ethanol (70 percent) and bleach (10 percent) or carbolic soap.
  • Use a disinfecting product on any items you touched that could develop the virus, including door handles!
  • Disinfect your tools, which you should do after every use anyway.
  • Never keep crop debris around if you suspect the houseplant has tobacco mosaic virus.
  • Consider getting rid of the infected plant and certainly never keep it around other houseplants.
  • Change out the seedling trays and/or potting mix if you assume an infection.

Is cigarette smoke bad for plants?

If you’re a smoker and a gardener, do you have to watch where you exhale? As we said earlier, cigarette smoke sure ain’t wonderful for your houseplants. Depending on how close you are, it’s possible for the surface of the leaves to get coated with pollution from the smoke. This affects the houseplant’s ability to photosynthesize, as their stomatal pores get blocked up from the smoke due to all the tar.

Fred Zimmer

I'm a lover of plants, animals, photography, & people, not necessarily in that order. Currently, I'm focused on photographing indoor plants & chachkies. I write & rewrite articles about creating an environment where indoor plants can thrive. I'm good at listening to music but bad at shopping to muzak.

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