5 Common Houseplant Myths That Seem True—but Aren’t

Do houseplants purify air? Should you water on a schedule? Find out which common care tips miss the mark—and what your plants really need instead.

If you need more tips, this is my system for simplifying houseplant care. Once you’ve got things organized, it’s smooth sailing.

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Is That Houseplant Tip Actually True?

Today we’re looking at some common houseplant myths and why they don’t hold up. Most of these tips seem logical—like misting plants or using water trays to increase humidity—but in fact, they have little or no effect on the plants.

I used to believe a lot of these things myself—mostly because they get repeated so often, even by so-called plant experts.

But once I started looking into the research, it became clear that many of these tips just don’t hold up.

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1Myth: It’s Best to Stick to a Watering Schedule

It’s tempting to simplify plant care with a set schedule: every Saturday, give them a drink. But the truth is, watering needs vary constantly depending on the type of plant and the growing conditions (light, temperature, humidity) which change throughout the year. That means what worked last week might be too much—or too little—this week.

Instead of sticking to a rigid schedule, pay attention to what your plants are telling you. When you learn to recognize signs like drooping leaves or dry soil, you’ll know when it’s time to water—no calendar required. This kind of care makes a noticeable difference and helps your plants stay healthy and resilient.

• Simplify Your Houseplant Care with This Easy Tagging System
  Start here to learn how to categorize your plants for simple, streamlined care.
• How Often Should You Water Your Houseplants
  Once you’ve organized your plants, this has good tips on becoming a good waterer.

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2Myth: Houseplants Purify the Air

This is one of the most persistent myths in the houseplant world—and it’s easy to see why.

The idea that a humble spider plant or that fiddle leaf fig is filtering the air in your living room is both charming and reassuring. But while some early lab studies hinted at this possibility, they were done in sealed environments, not real homes.

In reality, even if you packed your space with leafy friends, the effect on air quality would be negligible.

If cleaner air is your primary goal, a mechanical air purifier is still your best bet.

• Do Houseplants Really Purify Air?
  Find out how this rumor got started and how it persists today despite the science.

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3Myth: You Can Humidify Plants with Misting & Water Trays

Dry indoor air can be tough on tropical plants. So, many sources suggest placing trays of water (“drip trays“) near your plants to increase humidity. It sounds simple—but the effect is both minimal and temporary.

For a water tray to make a noticeable difference, you’d need a massive surface area of evaporation—or your plants would need to be in a tiny, sealed space.

What actually helps? Room humidifiers, grouping plants together (they share moisture), and choosing species that don’t mind the drier air of most homes.

You can still mist leaves (it can help remove dust) and use a water tray (they’re great for catching overflow), but don’t expect the relative humidity levels to rise.

• How to Increase Humidity for Houseplants
  Find out how to increase the humidity levels in your home, particularly during the drier winter months.

Thermometer-hygrometer (left) and Moisture Meter (right) | Amazon

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4Myth: Poinsettias Are Poisonous for Dogs

The saying “the dose makes the poison” perfectly sums up the toxicity of poinsettias (and many other plants). A dog would have to eat hundreds of poinsettia leaves to have a truly serious outcome—something that’s highly unlikely given how bitter they taste.

We’re all far more likely to get an allergic reaction from contact with the plant’s sap.

As always, use common sense when mixing pets and plants. If your pets are likely to chew or dig, it may be simpler to skip houseplants altogether.

I’ve had several cats over the years and some ignore plants entirely while others may nibble or dig. You have to decide what’s safest on a pet-by-pet basis.

If you do enjoy poinsettias over the holidays, use the tips below to grow them year-round.

• Growing Poinsettias: Year-Round Care & Reblooming Guide
  There’s no reason to get rid of your poinsettias after Christmas. Use these tips to grow them as houseplants year-round and get them to “bloom” again.

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5Myth: Talking to Plants Makes Them Grow

Talking to plants isn’t unusual—just as many of us casually greet pets, squirrels, or even inanimate objects. It’s a natural impulse and doesn’t feel strange at all.

As for the idea that talking helps plants grow, there’s no real evidence. A fun publicity stunt by the Royal Horticultural Society claimed it did, but it wasn’t a proper study and hasn’t been replicated.

So, no, talking doesn’t boost plant growth—but it’s still a perfectly fine thing to do.

• Does Talking to Plants Really Help Them Grow?
  When it causes no harm and makes you feel good, why not?

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It’s easy to get swept up in well-meaning tips—especially when they’re repeated everywhere. But as with most things in gardening, curiosity, observation, and fact-checking go a long way.

The more you get to know your plants and how they respond to their environment, the less you’ll need one-size-fits-all advice.

So go ahead—ditch the myths, trust the research and your experience, and give your houseplants the care they actually need. And if talking sweetly to them seems right, go for it.

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~Melissa the Empress of Dirt ♛