If you’re just starting to learn about how to care for houseplants, we recommend you check out our general guide that covers all aspects of houseplant care. If you’re trying to fine-tune your knowledge, learn about some of the misconceptions that may be holding you back. Some myths about houseplant care have taken on a life—and a brand—of their own. (Just adding ice is not the best way to water orchids, for example.) Other myths come from misapplying some basic facts about houseplants or else failing to recognize the ways in which houseplant care can be counterintuitive.
We have a separate page that discusses myths about potting and placing houseplants. In this space, we wanted to focus on dispelling popular myths about houseplant care practices including light exposure, watering, temperature, and soil quality.
Common Myths about Houseplant Care
- Water can Focus and Burn Plants in Direct Sunlight: This is just as common with watering the lawn and outdoor plants, but we’ve heard it about houseplants, too. The theory goes that the round water droplets can act as a magnifying glass to focus the sunlight and burn the plant. The theory makes a kind of sense, but it doesn’t represent the facts. Water can act as a magnifying leaves but doesn’t have enough space to focus the sunlight. There is something of this effect on plants with strong hairs that can capture water some distance from the leaf, but even then the science suggests that the cooling effect of evaporating water counteracts much of the added heat.
- Misting is Good for Houseplants: Arguably, misting houseplants can provide a few, isolated benefits. For one thing, it can serve as a de facto cleaning mechanism for leaves that have gotten dusty, for example. Under direct sunlight in summer, misting can provide a cooling blast and lower the humidity, if only for a few minutes. Misting air plants can help you procrastinate on a full watering soak. That’s about it—even then you need to be careful when misting houseplants. Too much and you can encourage mold and pests to get a foothold. If you want to increase humidity, a pebble water tray or air humidifier is a better method.
- Using Leaf Shine Products to Clean Plants: The popular home remedies for leaf shine include a mixture of water with milk or mayonnaise. There are also leaf shine products that make all kinds of outlandish claims. Yet, there’s no good evidence to think that leaf shine is any better than water. The important thing is to keep dust and other debris off the plant so the leaves can breathe. This can be done with water and a soft, clean cloth. Most leaf shine won’t hurt the plant directly, but some poorly made or poorly applied products may leave a residue on the leaves which can attract dust and make it even harder for the plant to breathe.
- Chlorinated Water is Harmful to Plants: This goes hand-in-hand with letting a full jug of water sit overnight to let chlorine and other chemicals settle. There is no evidence that the levels of chlorinated water you’ll find in tap water can harm houseplants. There is more of a debate about whether fluoridated water and fluoride exposure can stunt the growth of plants known to have a higher sensitivity to fluoride, like spider plants. Moreover, forever chemicals and systemic failures to municipal water can lead to unhealthy tap water for plants, pets, and humans. That’s why even though we’re not worried about chlorinated water, we use filtered water for some of our cherished houseplants just in case.
- Fertilizer will help weak, stunted growth: Fertilizer provides the final ingredients that houseplants need to take advantage of the extra light and warmth that comes with spring and summer. It is not a health remedy, and it’s not a cure-all for weak growth. Worse, if the plant’s growth has stalled as a natural consequence of the winter season, adding fertilizer could do more harm than good as it sits in and degrades the soil rather than getting sucked up into new plant growth.