Fact or Fiction: Plant Myths Debunked

We’ve all heard certain things about plants that seem a bit “old school,” and even a bit odd. Maybe your great aunt has been doing this certain thing for 50 years and her plants are all alive, maybe you have read about it online, or the care tag on a plant gave you the care info and you’re just not sure. Well, lucky for you we are going to go over the most common plant myths, or odd care instructions, to find out which is fact and which is fiction. In this post we will be covering the fiction side of things, so keep an eye out for the next installment which will go over the factual side!

Watering your orchids with ice cubes

This is a common and persistent idea passed on by a certain seller of orchids. I’m sure that you are well aware that orchids are a tropical plant that will not survive outside in a cold climate. Also, you may be aware that most orchids are epiphytes, which means that they grow on another plant, like a tree, but aren’t parasitic. They just sort of sit there and absorb their nutrients through their roots, not from the plant that they are sitting on. They get watered whenever it rains, which isn’t always on a schedule. They also get water that isn’t cold at all. Think about how warm the rain is on a summer day, now think about how cold an ice cube is. Very cold. So you are shocking the roots by keeping them at room temp and then putting ice cubes on the roots, which are made for the tropics, not for the arctic.

Rocks or brick in pot

This is an old school myth that just won’t go away. I’m sure you have heard that adding rocks, or brick, to the bottom of a pot will help with drainage. I am here to tell you that it is actually not a good idea to add rocks or brick. The water will sink to the lowest point possible, which is the dirt at the bottom of the pot. If you raise that bottom so the roots have less space, you are bringing that wet layer up to the roots, which in turn can make it more likely for root rot to occur. If you want to know about good soil additives for better drainage, we wrote a blog post about what you can add — you can read it here. And really, rocks and brick are heavy. Big pots are heavy. No one wants to add all of that extra weight to a pot — at least my back and I agree that it’s a bad idea.

Adding peroxide to the soil

This one is a double-edged sword. Adding hydrogen peroxide to the soil is a common thing to hear in the plant community. If you use the wrong strength, or it is not properly diluted, it is actually harmful and can be corrosive. So if you’ve ever heard that dumping some straight peroxide into your soil is a good idea, think again. Also, peroxide will kill off the beneficial bacteria that lives in your soil and provides your plants with nutrients. However, adding a certain mix of peroxide and water does have benefits, so you will have to stick around for the next installment that features facts to read about those!

Plants can’t be in a bedroom because they release carbon dioxide at nighttime

This is a common myth that I have heard, the fear that if you have plants in your room at night that they will absorb all of the oxygen and release carbon dioxide. Due to this (*cue scary music*) you will never wake up again! Okay, so yes, most plants respire carbon dioxide during the day, and do the reverse at nighttime, but you live in a house and not an enclosed rain forest. Let’s just think about this, the Earth’s atmosphere holds in gasses, such as oxygen, and the Earth is covered in plants. At night, all of the fauna, including humans, continue to survive. Also, your house isn’t fully airtight, neither is your bedroom. So, your house, namely your bedroom, is a safe place to sleep at night if you have houseplants. *It should be noted that I have well over 100 plants in my room, I sleep with the door closed, and as far as I am aware I am still among the living.

Misting leaves

Most of the plants that we keep inside live in areas that have a higher humidity than we have in our houses, so it would make sense to mist them to increase the humidity, right? The answer is actually no, misting does not do anything beneficial. Let’s think of it this way, when you mist, that water is only there for a few minutes before it dissipates. That means that the humidity is only raised for a few minutes, then it is back to the normal humidity level in that room. Also, it can make the soil moist, which in turn can encourage mold growth and fungus gnats. If you want to raise the humidity level around a certain plant, use a pebble tray, or a humidifier.

Plants grow bigger in bigger pots

Nope. No. Just, no. This is such a bad myth! In fact, if you put a plant in a pot that is much larger than the root ball, you are massively raising the chance of those roots rotting. The soil will take much longer to dry out, which means that those delicate roots are exposed to wet soil for a lot longer. Also, the plant will expend more energy on growing the roots to fill the pot than it will be on growing new leaves and flowers.

All houseplants need to be in a south facing window

Most houseplants actually will get sunburned leaves if they are stuck in front of a southern facing window. The best thing to do is to know what kind of plant you have and then look up the light requirements for it. You might find yourself surprised how many plants don’t need that high of a light level.

NASA Clean Air Study of 1989 proves that houseplants will improve the air quality in a house and increase the oxygen levels

The findings from this study are brought up frequently. If you haven’t heard of it, NASA decided to find out if houseplants would help filter/add oxygen to the air on space stations, since they can’t exactly open a window to air them out. Their study highlighted houseplants that they said did the best job of removing certain pollutants. Sounds amazing, right?! Well, sorry to to burst your bubble, but this study was conducted in a vacuum sealed space. I can guarantee that your house is not a vacuum sealed space. According to a memo released in 1992 by the U.S. EPA (Environmental Protection Agency) to achieve the amount of pollutants removed in the NASA study, you would need 680 in a normal size house. The average size of a house in the U.S. is a little over 2,600 square feet. Now, this is an ongoing thing that scientists are studying, so maybe in a year the NASA study will be in good light again.

Putting mayonnaise or milk on leaves to shine them

This myth is extremely common and we see this being brought up in our Facebook group all of the time. Both mayonnaise and milk are dairy, have you ever smelled dairy that dries? It’s gross and smells horrible. Same with egg based things (ahem, mayonnaise) that dry. The use of these two products can actually leave a residue on the leaves, gum them up and attract dust. This clogs up the pores and the leaves aren’t going to be able to breathe. Also, these can attract bugs and disease, neither of which are friends of the houseplant. Mother nature has been making leaves shine with rain since the beginning of time, so if you want those leaves to be nice and shiny and healthy, take a soft cloth, like a t-shirt, dampen it, and start wiping those leaves off. They will thank you for cleaning and keeping them healthy!

Most indoor plants need high humidity

Some of our favorite tropical plants enjoy higher humidity, but many common house plants can and will adapt to fairly typical household conditions. In fact, too much humidity coupled with a lack of air circulation can be a bad thing — it can lead to fungal infections, pests, and rot. A good target for humidity that can make plants and people happier is around 50 - 60%. You can buy a hygrometer (humidity meter) to figure out just how humid your house is or isn’t, and whether your actually need to adjust.

Yellow leaves mean that plant is over watered

One of the first diagnoses people like to trot out when they see yellowing leaves is that the plant is over-watered, but yellow leaves can mean a lot of things. Under-watering can cause yellowed leaves as well as over-watering, but water may not be the issue. Temperature (cold draft on a tropical plant?), light (is the plant in a dark corner?), and fertilizer (too much can burn, too little and the plant may lack nutrients), and even pests are also common causes of leaf yellowing.

Houseplants need watered at least once a week

Watering on a schedule seems like a good idea – water the plants every weekend, and you’ll never forget and accidentally kill one! Unfortunately if you water all of your plants on schedule, you’re probably putting them at risk of death by over-watering. Each plant will have individual needs and the best thing to do is assess each one as an individual — pot size, pot material, placement, and potting mix are just some of the factors that need to be taken into account. If you’re not sure, you can purchase a moisture meter to help you out!

You need to let your water sit overnight to let the chlorine dissipate

This one depends on what type of disinfectant is used in your local water. The two most common disinfecting agents are chlorine and chloramine – you should be able to find out which your municipality uses by viewing a water quality report on the local government web site. While chlorine may evaporate (especially with the addition of some air, like a bubbler) chloramine won’t, meaning your sitting water evaporates and leaves you with a more concentrated level of chloramine.

You need to re-pot a plant as soon as you get it

Not necessarily. It’s best to give a new plant a few weeks to recover (especially if it’s been shipped) and acclimate to its new environment. After that, if the plant is pot bound, roots are growing through the drainage holes of the pot, or it doesn’t seem to be growing as it should, it’s time to examine the roots and either prune or re-pot.

There are plants that can live in an enclosed space without windows or grow lights

Yes, and they’re called fake plants! All plants need light to photosynthesize, so a room with no natural light or supplemental grow lights isn’t a good place for your plants. One way around this problem is to have several hardy plants that can tolerate low light levels for a little while, and swap them out weekly so that they all get their time in the sun when not decorating your low-light or no-light space.

Succulents only need a tiny sip at a time

Nope! Just like other plants, succulents need and appreciate a thorough soaking when their soil has fully dried out. If you were sitting out in the sun all day you’d appreciate someone bringing you a nice full glass of water and not a teaspoonful, right? Water your succulents until the excess runs out of the drainage hole in the pot. How often you water them will depend on the type and size of pot, the time of year, how much light they’re getting, etc.

Hopefully these have answered some of your burning questions, and if not, well, hopefully they at least amused you. Remember to look out for our next installment where we go over the plant myths that are actually fact. Also, if you have any other questions, feel free to head on over to our Facebook group, House Plant Hobbyist. There are always members who will be more than willing to help you out!