How Not to Kill Your Houseplants, According to Botanists

If you’re like everybody else, you’re probably already halfway to murdering your ferns and cacti, and about to fail your goal of becoming a better plant parent this year. Don’t worry, all hope is not lost, we can still turn things around! And to do that, we recently consulted the experts—actual botanists—to learn what it takes to take care of houseplants. 

Botanists Christopher Satch of the New York Botanical Garden and Frank McDonough of the Los Angeles County Arboretum & Botanic Garden both gamely answered our questions about Plant Care 101, rookie mistakes, and their strangest garden hacks.

Apartment Therapy: Which indoor plants would you recommend for beginners?

Christopher Satch: When I’m teaching at NYBG, I am always asked about what the easiest plants are to care for. Honestly, that really depends on you and your lifestyle. You have to remember that a plant is a living thing—think of it as a low maintenance pet.

If you are the kind of person who is doting, and wants to look, feel, and interact with your plant daily, you might want to get a plant that wants more care, like an air plant, orchid, or fern. If you are forgetful, or travel a lot, something that wants to be left alone, like a snake plant, marimo ball, or cactus/succulent would be best.

AT: What is the biggest mistake that people make when it comes to plant care?

CS: There are a few, but one of the biggest mistakes that people make is not giving their plants enough light. Light is food for plants. They literally eat the light. You often read anecdotal online stories of people being afraid to “burn their plants,” but in reality, it’s too dark indoors to really burn a plant.

Most folks mistake a fungal infection for burning. If a plant is not getting enough light, then the plant will drop its leaves (figs are especially good at that, including the popular Fiddle Leaf Fig) starting with the bottom most and work their way up. Any plant will only hold as many leaves as the amount of light it’s getting can support.

Frank McDonough: Providing drainage for the plant—putting them in a pot with no drainage holes, allowing them to sit in a tray full of water for too long, potting them up in a potting soil that has very little drainage material (like sand, perlite, pumice, etc.) in it. This will cause the plant’s roots to rot and kill the plant.

AT: What are the signs to look out for to know if a plant is healthy? Unhealthy?

CS: The best thing to do is start off on the right foot. Many folks will just grab a plant they like, but it’s super important to start right. Always inspect a plant before buying. I’ve had to turn down plants I’ve really really wanted because before buying, I found spider mites, or other pests on them… and it’s really tough if it’s the last plant and you really want it, but sometimes you just have to turn it down.

Always buy a plant with new growth, and check under the leaves for pests. New growth means that the plant is actively happy and growing.

FM: Unhealthy plants have senescence (the leaves turn brown or yellow and fall off). They’ll easily pull out of soil because the roots have rotted out. Also watch out if new leaves are distorted and quickly fall off or if the plant smells of rotten eggs. 

Healthy plants have leaves that are full, and new growth occurs.

AT: What are your top tips for keeping house plants alive?

CS:

1. The failsafe rule for all plants is to place them in a window. The more light, the better.
2. Don’t know when to water? FEEL the soil! If dry, then you can water. If moist, then hold off.
3. Seasons changing will affect how long you should wait between waterings.
4. Water fully by saturating the soil with warm water, letting it soak for a few hours, then drain.
5. Always check on your plants every few days. It’s rare that you will need to care for a plant every single day.
6. Always re-pot after buying into a larger pot (go 1-2” larger… when we say a plant is a 4” plant, we are talking about pot diameter, not height. For example, plant a 4” plant into a 5-6” pot).

FM:

1. Choose the right plant for the light and care it will receive (see above if you are a plant killer).
2. Trim dead material off of your plants. Dead material left on plants can be a breeding ground for bacteria and fungus that can kill them.
3. Keep feeding to a minimum. Go with no more than half the dosage recommended for plant foods that are labeled for use on houseplants. Overfeeding plants makes them susceptible to insects and disease. 
4. Never use plant polish—it is death for a lot of plants. 
5. Consider using plant lights and a fan to increase light and air circulation.

AT: We’ve heard of some pretty odd plant hacks like the one about rubbing mayo on leaves. Do you have a strange plant hack you could share with us?

CS: While I’m dubious about the mayo trick, freshly-ground up cinnamon (that you grind yourself, not pre-ground) used on orchids is antibacterial and antifungal, and can help stop the spread of fungal infections in leaves and roots.

Also, not really a hack, but had to slip in—yellow leaves do NOT always mean overwatering. Yellow leaves are a general distress signal, and could mean anything. You will need to inspect what is going on around the plant to figure out the cause.

FM: I will use a Swiffer duster on my plants every once in a while to keep them from accumulating dust.