Air plants, cacti, herbs and more: How not to kill your plants at home if you're not an expert

Like many Singaporeans, I entered the fascinating world of plants during the COVID-19 pandemic. Along the way, I’ve unalived many, many plants. I shudder to think about the succulents, begonias (oh, such fickle beauties they are), air plants, orchids, and even a cactus or two that lie in the mass grave of my Garden By The Window.

And I’m not alone, from the conversations I often overhear in plant shops and nurseries. From questions such as “can this be placed in the (insert: Balcony/corridor/living room/bedroom/kitchen) of my HDB flat?”, “how often do I water it?” and "will it survive?", I feel the trepidation in the voices.

The assurance I got recently was that plant murdering is part and parcel of the hobby. Even the professionals have done it – not on purpose, of course. Take Vincent Chia, the founder and CEO of Tropic Planners & Landscape, for example.

“I have killed ferns and orchids in the beginning, not understanding their growing needs,” he said. This is an expert who has a diploma in landscape design, and has won prestigious accolades in France, Japan and previous Singapore Garden Festivals. He’s also participating in this year’s festival in the Balcony Gardens Competition.

“Uncountable!” exclaimed Daniel Goh when asked what his plant-killing record currently holds. “You can only minimise killing them,” said the man, who has been growing air plants for over 10 years and is the owner of an Avatar-inspired nursery named, well, Airvatar.

“Many people say, ‘I don’t have green fingers’ or ‘I’m a plant killer’. It’s about understanding the plants,” said Goh. “As long as you know their needs and provide them with the right environment, they’ll thrive. It has nothing to do with having ‘fire’ in your hands!” he laughed.

Fire fingers or not, below is a list of tips and tricks to help you outgrow your plant-killing streak (hopefully). “It is alright to make mistakes,” said Chia. “If the plant did not survive, you can find out why and try growing it again. If it is not suitable to be grown at home, you can move forward knowing that you now have a better understanding and knowledge about the plant.”

ARE THERE PLANTS THAT ARE EASIER TO KEEP ALIVE?

If you ask Goh, he'll say air plants. "People feel stressed when their plants don’t grow well. There are so many things to consider… too wet, die; too dry, die. Then, you must fertilise and deal with pests.

"I tell them, grow air plants! They don’t attract pests like aphids and mealy bugs because they are not fleshy and pests tend to go after fleshy plants."

Goh's air plant recommendation for newbies is the tillandsia ionantha. "They are cute, like little sprites and are easier to keep alive. Their flowers are also very pretty."

Plus, air plants are less likely to wither away when you're on holiday for one to two weeks. "At most, they’ll be dehydrated but they won’t die. You don’t have to worry about getting someone to water them and risk killing them. Before you leave, give your air plants a thorough misting."

BUT I HAVE KILLED AIR PLANTS BEFORE. WHAT DID I DO WRONG?

When it comes to air plants, Goh has his LAW – light, air flow and water – to keep his over-1,000 air plants happy in his nursery and HDB corridor. “Air plants need bright, filtered light,” he said. “Next to an opened window is the perfect place because you get that kind of light. Such a location may also give the air plants a few hours of direct morning sun, which is especially good for all plants.”

Next, air flow “because air plants absorb moisture and nutrients through their leaves”, said Goh. If you have yours in a sealed jar or other container, it’s time to break them out. They may look pretty but you’re starving your plant babies.

And finally, water. Goh isn’t a fan of dunking air plants in a tub to water them as “Singapore’s humidity is very high, so it’s difficult for the excess water to evaporate”. “I would recommend misting air plants instead,” he said. Remember: Mist the leaves, not the roots.

As for the misting frequency, create a routine, so you don’t have to second-guess if it’s time to water your plant babies, said Goh. “Gently mist them until they turn a darker colour to simulate the morning dew and fog they love, about two or three times a week; but not until they drip with water.”

Fertilising, however, is optional, said the air plant artisan. “If you want to enhance or quicken the growing experience, you can use liquid orchid fertiliser. It makes the airplant hardier as well,” he said. “Dilute the fertiliser to one-tenth of the recommended dosage. Then, pour it into a mist bottle and mist every two weeks.”

WHY DO MY HERBS ALWAYS DIE AFTER A WHILE?

Growing basil and rosemary seems like a good idea to keep your kitchen stocked with fresh herbs. But it isn’t practical anymore when they keep dying. What are you doing wrong?

It may not be your fault at all. “Herb plants such as basil and rosemary have a lifespan of about one to two months, so they won’t last long,” said Chia. “It’s good to let people know that, so they don’t get disheartened.”

But that doesn’t mean you have to keep buying a new pot of basil. “You can propagate or grow new herb plants by using their cuttings,” said Chia. The same goes for chilli, it seems. “You can grow from seeds after the parent plant starts to get exhausted and dies.”

I EVEN KILL CACTI. HOW DO I STOP DOING THAT?

In most cases, over-watering is what kills your spiky collection. To avoid waterboarding your cactus, try the disposable chopstick method, suggested Chia.

Stick the chopstick next to the cactus’ stem vertically all the way down to the bottom of the pot. Pull it out and see how much of the submerged portion of the chopstick is moist. For cacti, the chopstick should be bone dry before you water it, which could be every seven days, 10 days or longer, depending on the air flow in your home.

Or try bottom watering to avoid over-watering, suggested Goh. Fill a container with water and place your cactus pot in it. The water level in the container should reach about a third of the pot’s height. Then, let the pot suck up the water for about 20 minutes to an hour. You’ll know it’s ready when it stops absorbing water.

“It’s a less messy way because there’s no water draining from the bottom of the pot. Also, it minimises washing away the nutrients in the soil,” said Goh. But even with this method, you’ll need to ensure the soil is coarse and drains well.

HOW DO I TELL IF I'VE OVER-WATERED?

“When you see leaves hanging over, it is easy to assume the plant needs more water but it could be that the roots are already drowning,” said Chia.

To be certain, you’ll have to get dirty. Take the plant out of the pot and remove all the potting medium to inspect the roots as soon as possible, said Chia. “We need to trim away the rotten parts, spray fungicide and repot the plant with fresh soil – and maybe we can salvage the plant.”

To avoid over-watering your plants in the first place, try the aforementioned bottom watering or chopstick method. “For most tropical plants, water when the moist portion is about 20 per cent of the submerged chopstick,” said Chia.

By the way, if you’re watering from the top, don’t just chuck a cup of water into the soil and call it a day. You need to keep going until water starts to drain from the holes at the bottom of the pot. This ensures that the soil is sufficiently wet and the roots can access the moisture.

WHY DO THE LEAVES LOOK BROWN/YELLOW/WHITE AND DRY?

In tropical Singapore, where there is no lack of sunlight, plants may actually get sunburnt if exposed to more than six hours of direct sunlight. You’ll know when the leaf edges or entire leaves start to turn yellow or white. Leaf edges turning brown and dry are other red flags.

“If it’s one or two yellow leaves, it could be a sign of insufficient watering,” said Chia. “If there are brown leaves, it could be that the location is too hot for your plant. You can try relocating the plant somewhere with semi-shade to see if it recovers. If the problem persists after a week, it could be that the roots have issues.”

The direction the leaves face can also be a clue. “If it’s too hot, the leaves can turn away from the light source,” said Chia. “So it’s time to move the plant further away from the window.” In general, it should be okay to place the plant about 1m to 2m from the window, he said.

What about cacti? “They have to be in as much direct sunlight as possible,” said Chia. “They need the heat to make them hardy.” Desert cacti may require direct sunlight for about four hours a day, while the tropical or jungle cacti can tolerate indirect light. You’ll know there isn’t sufficient light when your cactus – or other plants – starts to show signs of etiolation or grow weak, long stems.

WHAT DOES IT MEAN IF PARTS OF THE PLANT FEEL STICKY?

You have a case of plant vampires better known as aphids and mealy bugs. As these sap-sucking pests feed on your plant, they excrete a sticky honeydew that encourages a fungus called sooty mould to grow.

Aphids can look like small green, yellow, brown-red or black bumps on plant stems and the undersides of leaves. Mealy bugs, on the other hand, look like cottony, white spots on the stems, underside of leaves and on roots.

“If you don’t want to use pesticides, you can try a simple remedy by mixing a little bit of dish detergent and water,” said Chia. “Mix it in a spray bottle and spray it on the plant. After the solution dries, wipe the leaves with a clean cloth.”

If, after all that, the plant still doesn’t look like it’s recovering, you may have root problems, said Chia. “It’s usually a sign of fungus if the plant looks soft and doesn’t seem to absorb water when you water it.” You’ll have to take the plant out of the pot, remove the soil, cut away the affected area, and spray fungicide on the roots, he said.

Then, keep your fingers crossed that your plant survives.