Researchers develop a new houseplant that can clean home air (2018) | Hacker News Reader

Researchers develop a new houseplant that can clean home air (2018)

washington.edu

103 pointsknown41 comments

I love pothos! They are really easy to propogate, not hard to take care of and even without modification already pretty good at filtering air:

https://en.wikipedia.org/wiki/NASA_Clean_Air_Study

I have been skeptical about these claims in the past. I really like this tear down of the previous claims[0]. Since this articles has some specificity, chloroform and benzene, with a mechanism it seems like some more solid ground, instead of the vague claims of pollutants. This may be a step in the right direction though I must admit this is outside of my expertise. [0] https://www.gardenmyths.com/garden-myth-born-plants-dont-pur...

This 10y old TED talk [1] did trails and claimed you need three plants for clean indoor air:

Areca palm, mother in law's tongue and money plant.

===

[1] 4min https://www.ted.com/talks/kamal_meattle_on_how_to_grow_your_...

Floating around this week is this video https://www.youtube.com/watch?v=1Nh_vxpycEA wherein a person sits in a sealed off cube full of plants and carbon dioxide monitors, with an EMT on the other side for safety - the person claims that 300 ppm of outside air was fresh, and now 400 ppm is fresh - but that indoors, it can easily climb to over 1000ppm and that there might be a significant cognitive decline associated with it.

I was looking for a nice wall receptacle for a hallways that measures carbon dioxide inside my house because I will go for weeks at a time without getting a proper air-out. In northern new england, honestly, it could be months for all I know. Only a few random door openings and the leakiness of the house are my exchange.

I don't know how accurate their claim is, and it's certainly a universal solvent to consider stale air is the reason a person is behaving a way. Measuring the levels and being aware of it seems worth 60 bucks, if it's actually a factor in our rationality.

Even in a well-insulated house with all the doors and windows usually kept closed, you're going to get a lot of air exchange with the outside world. Any problems are likely to be very localized -- one room.

Yeah, I don't think the "envelope" is considered well _sealed_ unless your home is insulated via spray foam.

When you read studies like this always make sure they did proper controls. Studies in the past have done the same experiments again after removing all the leaves etc. and get the same cleaning of the air. Turns out it was the microorganisms and absorption in the potting soil transforming and absorbing the noxious compounds.

This one seems to have been done right but they used levels of contaminants much higher than would be found in a home.

It'd be interesting to compare using a plant like this and what the concentration of various chemicals are in common homes against simply having proper air turnover in the home. If you're turning over the entire volume of the house every X hours by bringing in fresh air from outside, like modern building recommendations suggest, then this should reduce any buildup of chemicals much more effectively, at least to levels which are only slighly higher than the outside air.

There are many websites claiming that various plants can clean the air from allergens and pollutants while scrubbing co2 and providing oxygen.

Kamal Meattle even claims that a handful of large plants are enough to sustain a person without any external input! http://greenspaces.in/blog/ted09/

I cannot find metastudies and reliable scientific data on the topic. Most sources cite only the same old NASA study.

Any help?

> Kamal Meattle even claims that a handful of large plants are enough to sustain a person without any external input!

This is wishful thinking. If you run the numbers, it's clear that to produce enough oxygen for even just one person you need a lot more plants than anyone can reasonably grow inside their homes. You would need 8 lbs of new growth per day to match the amount that a person consumes.

> The average adult, when resting, inhales and exhales about 7 or 8 liters of air per minute. That totals about 11,000 liters of air per day.

> Inhaled air is about 20-percent oxygen. Exhaled air is about 15-percent oxygen. Therefore, about 5-percent of breathed air is consumed in each breath. That air is converted to carbon dioxide. So, as far as how much air is actually used, human beings take in about 550 liters of pure oxygen per day.

https://www.sharecare.com/health/air-quality/oxygen-person-c...

> Plants produce 22 L for every 150 g of growth. They would need to increase in weight by 3.75 Kg (8 pounds), each day, to produce the oxygen used by one person.

https://www.gardenmyths.com/houseplants-increase-oxygen-leve...

How do I get a cutting of this plant?

Go to a local Walmart/Target/Lowes etc. Hardware stores and even some supermarkets have them. If not, literally just post a photo on facebook asking friends for some or ask around at work. It's extremely common because you really can't kills it unless you actively try usually. I water mine once a month usually and it's happy. The only thing I would say is if you get a cutting, try to multiply it as fast as possible so you can experiment with which windows/light will help it grow the best.

Not these particular ones, they have been genetically engineered to do this job. They added a gene from mice liver that takes out certain toxins. I think/hope the team plans to commercialize the plants though.

It's funny you say that. I've killed two in the last few months. I've tried super low light, normal light, and my succulent shelf. I've tried watering regularly, and never watering. The leaves just reliably turn this soft brown and then it dies back to the vine itself then entirely dies off. (Seattle, indoors)

Nothing makes me feel quite as incompetent at gardening as when I'm able to kill the plants everyone else says should be foolproof ><

It is impossible to over-water this plant. It will grow in only water, without soil, provided the water is rich in nutrients. I stuck a tiny sprig in the corner of my aquarium, hanging over the top edge, and it has now grown almost across the entire room ( https://1drv.ms/u/s!AvN2CzyomlrtiddUmysi3I51CdE39A ). Make sure there are several sets of "nodes" or bumps on the stem that are under water or soil level, and keep soil really moist in general.

Ugh that looks amazing, I'm so jealous. Looks like you get more light than I do, but I'll try on the "more water" side, as well as fertilizing. Thanks for the tips!

Just to clarify are you getting cuttings that are dying or established plants in a container? If you are getting cuttings make sure that you are cutting nodes and not just the leaf steam if you are trying to propagate. I've added a video that I've used to know where to cut the vine for propagating.

[1] https://youtu.be/xpmdo_0CZrU?t=110

I'm getting established plants in a container, from a local garden place. Small (2-3 inch) pots, but established.

The _ONLY_ thing I can think of after watching your video is that the house gets cold at night, since we only keep the bedroom fully heated, so my current attempt is on my cactus shelf which I keep warmer.

(The link is appreciated regardless, if I ever got one to "stick" I'd love to propagate it)

Chills can easily kill it. In winter's Seattle, try non-tropical species first. Could suit you much better.

I've generally avoided tropical species exactly as you say, but after having decent luck with some of the "you can't kill this" plants (zz plant, sansevieria, some ferns/aloe/simple cacti) I figured I'd throw a wider net.

Unfortunately our house both gets _very little_ light and is often quite cold so that already precludes a lot of options. Some day I'd love to live somewhere that allows the "room full of giant bushy plants indoors" setup.

Aspidistra elatior could work. A modest (boring) slow-growing creature. After some years can produce small and very alien flowers eventually.

I have had the same pothos plant for the past decade. Once it was a single small plant. It's now a half dozen large plants. Some suggestions:

- If you're fertilizing them, maybe stop doing that. Fertilizer is good when done right, but it's easy to overdo it and burn your plants. Pothos can survive for years in the same potting soil, so stick to plain water and see how they do.

- Give them a small cup of water twice a week. A total of 250mL per week is probably good.

- Put them anywhere near a window, but maybe not in direct sunlight.

- Keep the temperature around 20-25°C (room temperature).

That's basically all I do. The only time I've managed to harm them is from using too much fertilizer.

If it makes you feel any better I also manage to repeatedly kill plants with a reputation for being unkillable. I just now have a broad leaf plant which has somehow decided to bend towards the floor instead of standing up straight. with all the fronds upside down it is quickly dying.

If you post a link with a photo I could take a look to it and maybe find the problem.

Appreciate any advice you could offer: https://imgur.com/a/0s7J0WQ

Looks like a Dracaena fragrans, a tropical tree from Africa that is a very popular houseplant. Unfortunately your plant seems very ill. Roots and stem are dead and probably hollow. Only the upper part is alive for now, but unable to get water and nutrients so is dying.

This happens typically by a fungus attack when the plant roots are left in stagnant water that gets too cold at night. The fungus kills the plant from below.

At this state your best try would be to discard the old plant and use the green part as a cutting. Unroot the plant, use a sharp knife to remove slices of black and rotten tissue (Work from below towards the upper part). With luck you will find green and healthy tissue eventually.

Now clean this upper part and cut all leaves by half (to reduce evaporation in a rootless plant), if the stem is wrinkled put it in clean warm water for an hour. If available, put some cinnamon powder over the wounded area, let dry for a few hours and then repot in a new recipient with some moisture. You can use a half plastic water bottle with holes at the bottom, (thus you can take a look for new roots).

The plant will probably not do too much until spring, but this is normal. To be successful you will need a warm area (71-75Fº), some light, and good soil.

About the soil. The cheap stuff in your photo is probably the main reason for your problems to keep plants alive. You are using a poor quality mix of compost and polystyrene, too dry and low in nutrients. Don't recycle it!. Just pick some standard soil from a garden, an orchard or (even better) a forest. Normal earthworm soil will be great.

Is still possible to save it. Dracaenas root easily from cuttings (the inferior leaves will be sacrified in the process by the plant but new leaves will regrow soon after the new roots are ready). Good luck

Thanks!

This plant needs to be propagated as much as possible.

I'd be interested to see how effective algae and mosses are at cleaning air, too, since they are so easy to grow and propagate.

This group is working on that. You can currently buy a moss engineered to put fragrance in your home: https://www.mosspirationbiotech.com/shop

How much chloroform and benzene is there in the air? The article doesn't say (or did I miss it?). It seems to imply that the concentrations are high enough to be a problem but avoids saying so outright; so is there any point to having these plants?

I'm not an expert, but I found a paper that surveyed the indoor air concentration of various pollutants in homes. The lower number is mid-range of measurements, while the higher number is the upper bound.

    chloroform: 30–100 μg/m³
    benzene: 2–10 μg/m³

A volume reference might also be handy. An 800 sq ft apartment (~80m²) with a ceiling height of 8ft (~2.5m) is ~200m³.

Source: Figure 5 of "Hazard Assessment of Chemical Air Contaminants Measured in Residences" (2010) by Logue, J.M. https://cloudfront.escholarship.org/dist/prd/content/qt6gr6d...

Depends on the house, and what molds are living within it.

And whether you've got a petrol lawnmower nearby and your water is chlorinated.

An awful lot if you're a smoker.

"Researchers notice that Araceae clean home air, as is known since thousands of years" would be a more accurate title

And you don't need Scindapsus necessarily. You can have a more compact Spathiphyllum in your working lab. It can help removing benzene and also formaldehyde from the air.

https://www.sciencedirect.com/science/article/abs/pii/S13091...

The paper is behind a paywall, but my question is how much gas can the plant remove? How many plants would be required to have a meaningful effect on a room?

fun fact. if the plant dies it will release it's gas again like other plans. seems kind of futile 'solution' just dumping the problem on future generations .. as always

This is incorrect. Formaldehyde for example is broken down into CO2 or at least to formate which is non-toxic.

And while benzene might accumulate in normal plants, this one has an enzyme which oxidizes benzene so it does not get released later.

It was done in 40 mL VOA vials at very high concentrations of gas.

I don't think you could extrapolate.

I'd say if you care about air quality, Step one - filter PM. Step two, big plants that are easy to grow. Step three narrow down the plants you need.

Check out https://en.wikipedia.org/wiki/Sci-Hub

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