The Expert’s Guide to Taking Care of Your Houseplants

This article originally appeared on VICE Germany.

Most people have at least one death on their conscience – one plant death, specifically. Houseplants are an incredible source of joy, especially if you live in a concrete jungle, but it’s also so damn hard to keep them alive. We all know the basics: water, light and above-freezing temperatures. And yet, even if you think you’re taking good care of them, they’ll sometimes start losing leaves or turning yellow.

René Wadas is a professional gardener and plant doctor with 30 years of experience in the industry. He answered all of our dorky questions so you’ll no longer have to keep burying your uninstagramable houseplants in the organic waste.

VICE: Hey René. What are the three easiest houseplants to care for?
René Wadas: I’d recommend the cast-iron plant, the ZZ plant and the monstera. The cast-iron plant needs a bit of water and fertiliser now and then, but otherwise it can be left for years. The same goes for the ZZ, which actually only thrives if you forget all about it. The monstera has aerial roots, so when you go on holiday you can simply put it in a large bucket of water, and it will take care of itself.

How do I know how much light a plant needs?
The plant shows that through its leaves. As a rule of thumb, the darker the leaf, the more it’ll like living in the shade and the less it’ll tolerate the sun. The lighter the leaf, the more it’ll need light. If the plant is hairy or thick-fleshed, it can be placed in full sun.

During summer, you often have to choose to either place your plant in a hot room full of sunlight or in a dark and cool space. I always pick the dark ones. How long will my plants put up with that?
Not for long. Plants need light. They use the summer to stock up on reserves for the winter, so you should let them have the light. If you want to cool down a room, you can just get large plants because they sweat out water. A monstera is the cheapest air conditioner for this season of high energy prices.

I’ve recently got an Alii fig because it’s easy to care for, but I have absolutely no idea how often I should be watering this thing.
Basically, you can test this by sticking a finger in the soil: If the top layer is dry, you water the plant.
It's always better to water it a little bit multiple times than a lot at once. If the ficus is in a brighter place, it’ll need more water; if it’s in a darker place, it’ll need less water. In the winter, they’ll need hardly any; in the summer, a lot more. 

By the way, even cacti need to be watered sometimes: Hardly at all in winter, and a little bit every four weeks in summer. A cactus that never gets water will eventually dry up.

Speaking of watering, I usually just chug some into the pot. Is that actually correct?
There are a couple of ways to do that. You can either water them from the top or pour water into the bottom of the pot and let the plant draw it up itself. If you only water from the bottom, the capillary action [the system plants use to draw up liquids] will also transport the nutrients only upwards. So feel free to change how you give them water every now and then. Plants also like it when you spray their leaves with stale, lime-free water.

I'm going on holiday for two weeks. How can I make sure my plants survive?
There are two tricks you can do with bottles. For the first one, you take a plastic bottle, drill small holes into the top, fill the bottle with water and plant it upside down inside the pot. A little water will always drip into the ground and the plant will survive. The second trick works with a wine bottle: Take it to your neighbours together with your flat’s keys and ask them for help.

Is it true that you should shower some plants to make them feel like they are back in the rainforest?
It’s better to not shower plants actually, unless you want to quickly remove the dust from the leaves. If you shower them, use rainwater – that's very important. Can you name me one rainforest where it rains lime water? Plants that actually live in the rainforest need a slightly acidic soil. So if they do require a showering, just put them out in the summer rain.

Do you need to change potting soil? If so, how often?
Basically, you want to change the potting soil when you repot. Repotting is necessary when the roots of the plant are showing either underneath or above the pot. If that’s the case, take a pot that’s two fingers wider than the old one and add new potting soil. And please use normal potting soil – those so-called special mixes are nonsense.

You can tell if potting soil is of good quality if it clumps together and then falls apart again after you’ve squeezed it in your hand. Cheap potting soil usually has so much compost that the soil is all squishy – plants don't feel comfortable in it. You can't go wrong with normal, medium-priced potting soil. 

Do you have to fertilise your houseplants? If so, with what and how often? Are there alternatives to artificial fertilisers?
Of course. Plants don't live on air and love alone, they also need nutrients. In nature, the roots have much more space to spread out and search for nutrients. But in our homes, the plants live in small pots, so we have to feed them.

There are lots of great natural, vegan fertilisers with minerals and molasses available everywhere you can buy plants. You should do this every week, but only during daylight savings time. Once the clocks change back to standard time, you stop fertilising and don't start again until spring.

What can I do if my monstera has grown over my head?
As a gardener, sometimes you need two things: a steel heart and sharp scissors. So just trim the overgrown parts. You always trim plants on a leaf axis [where the plant’s stem meets the leaf] or where there is an aerial root. You can then pot the cutting back into potting soil, and then you’ll have a second plant to bring to your next party as a gift. Also, you should always trim a plant after it flowers. Removing old flower stems allows the plant's energy to go back into the leaves.

What should I do if my plant’s leaves have dried up around the edges? Cut off that part? Remove the whole leaf? Do nothing at all?
Those brown leaf edges are caused by watering too much or too little, or they could also indicate a lack of nutrients. It’s actually a good warning sign, but you have to reflect on what you’ve done wrong.

Are there some houseplants that just drop leaves in the winter no matter what you do?
Houseplants are mostly evergreen. They may lose a few leaves here and there, but if they’re losing too many in the winter, it means they didn’t store enough reserves during summertime. This means that we haven’t fertilised them enough. So, in order to survive, a plant will drop all the leaves it doesn't need. If it gets really bad, some plants will have a stress-induced early flowering to preserve the species. Of course, that won’t work in a houseplant’s favour, because its seeds won’t be dispersed by wind or animals.

What’s a common plant care mistake that’s easily avoidable?
Fertilising. Most people don't fertilise enough. The second one is too much water.

Is there a houseplant that doesn’t deserve the hype?
Every plant deserves the hype. It’s important to surround yourself with plants. I find the nicest people always have lots of plants.