10 house plant mistakes you can avoid, according to a soil researcher

This is where you might be going wrong, according to a house plant soil researcher

A collection of houseplants in closeup
(Image credit: Евгения Матвеец / Getty)

For a happy green home, you'll want to avoid these house plant mistakes to ensure that your indoor garden stays lush and healthy. While there are some house plants that are relatively carefree, we know all too well that it's easy to slip up, leading to problems like yellowing, frazzled leaves, or even more dramatically, plant death. 

The best indoor plants are often presented as low-maintenance, but the truth is that no Monstera, Aloe Vera or even Money Tree is ever totally maintenance-free and most will begin to suffer if cared for incorrectly.

Fortunately, all of these errors can easily be avoided and you'll be pleased to know that learning about them will likely mean you'll become a more relaxed plant parent in the long term, as often the best form of house plant care is simply to let them do their own thing...

1. Over-watering

Over-watering is the number one house plant mistake people make. People more commonly kill their plants through too much kindness than neglect. Jules Giuliano, the lead soil researcher at Rosy Soil, tells us that 'many plants need a wet & dry soil cycle to perform properly. If you think you need to water again, use your fingers to inspect the soil & determine if it's necessary.'

In other words, if your plant soil has dried out it probably doesn't need watering. If water is in the saucer under a plant pot, you are definitely overwatering. Repeated overwatering will lead to fungus gnats and root rot - and eventually, the plant dying. Yellowing leaves can also indicate overwatering. 

The course of action is simply to leave your plant alone. If you see fungus gnats, you need to take more active measures to rescue the plant: repot it into a new pot with fresh soil. 

A woman checking whether houseplants need watering

(Image credit: Richard Drury / Getty)

2. Under-watering

Some people go to the other extreme and don't water their plants at all.  While there is a very limited number of plant species that can go without water for many months, including air plants and some cacti, most plants need regular watering to survive. Contrary to popular belief, this includes succulents and cacti – they may only need watering once every few weeks, but never watering them will kill them. 

3. Not giving your plants enough light

Giuliano urges houseplant enthusiasts to 'make sure your plants have sufficient light for their needs, whether from the sun or an artificial light source.' While some plants will tolerate relatively low-light conditions - dracaenas are great for a shaded corner in your living room - all plants need light to photosynthesize and survive. Sticking a plant in a completely dark bathroom and hoping for the best will inevitably result in the plant dying. 

As a rule of thumb, you should position most houseplants in a bright spot with indirect light. If your houseplant is a flowering plant - for example, growing pelargoniums indoors - it will need more light, ideally sunlight. Still, to prevent lunchtime sun scorching your plants, you may want to protect them with a net curtain or move them away from the window by an inch or two. 

Houseplants in white baskets in a modern living room

(Image credit: Carol Yepes / Getty)

4. Placing houseplants in direct light

This brings us to the next point: most plants people use as house plants come from tropical rainforests where they are shielded from harsh direct sun by dense tree canopies. Direct sunlight, especially during lunchtime, will kill your calatheas, rubber plants, and many other plants not adapted to direct light. 

Cacti and succulents are exceptions - they like the direct sun so can be positioned right on a sunny window sill.  

If you are in doubt, look up your plant light needs online before you decide where to place it. Plants don't like being moved around too much so it's best to decide on a spot before you've bought your plant. 

5. Repotting too often

Many house plants are slow growers and don't need a bigger pot until they've outgrown their current one. Many will actually experience stress if you disturb them too often. As a general rule, repot your houseplants every couple of years until they've reached maturity. Once they've reached their full size, just keep them in the biggest pot they'll need for the rest of their lifespan. 

6. Never repotting

On the other hand, if you never repot your houseplants they will suffer from becoming root bound and from the lack of nutrients in the soil. Soil has a limited supply of nutrients and once your houseplant has worked through it, it will need fresh soil. 

Plants that are rootbound won't die straight away -they actually will keep going for quite a while, but they won't thrive. You'll probably start seeing poor growth, disease, and leaves falling off. 

If your plant is toppling in its current pot, it definitely needs repotting. Go for a pot one-third bigger than the last one and make sure it has drainage holes. 

7. Watering with tap water

Not many houseplant owners know this, but watering houseplants with tap water is often a bad idea. While not all houseplants are equally sensitive to the minerals and residues found in tap water, some really suffer from the chemical imbalance that creates in the soil. Calatheas will often start developing spots on their leaves as a stress response to the common chemicals such as chlorine found in tap water. Watering orchids with tap water for example isn't recommended, and you should choose rain or filtered water instead.

A woman watering colorful orchids from a copper watering can

(Image credit: Maryviolet / Getty)

8. Incorrect watering technique for the plant type

While it is true that most houseplants just need watering from the top with a watering can, some have more complex watering requirements. Some succulents and bonsai trees benefit from below – just stand the plant in a saucer filled with water for 10 minutes. Orchids do best also being watering in a large tub or the sink. 

9. Not using fertilizer 

Giuliano advises that 'if you would like to see a new leaf, make sure to feed your plants properly. Compost is a great organic amendment to use as a top dress on your plants.'

Remember: there is a limited supply of nutrients in houseplant soil and you'll want to replenish them before it's time to repot your plant into fresh soil.

10. Not cleaning your plants

Did you know that, just like humans, houseplants enjoy a wash? There are all sorts of techniques for cleaning your house plants, depending on the plants. If your plant has large leaves. e.g. a rubber plant, you can simply wipe the leaves with a damp microfiber cloth. Other houseplants will enjoy being stood in your shower (in cool water, of course, not hot). 

Even misting your houseplants counts as cleaning and will help the leaves breathe better.

What is the most common problem with indoor plants?

Overwatering, which is number one on our list of houseplant mistakes. Stop overwatering and your plants will be doing much better. 

How to I know what's wrong with my house plant?

House plant problem symptoms can be confusing for novice houseplant owners because the same symptom can indicate a different problem in different plants. One plant may drop its leave when it's overwatered, while another may do so because it's not getting enough light. 

You should always look up specific plant requirements and problems online as there's no one-size-fits-all answer. 

Anna is a professional writer with many years of experience. She has a passion for contemporary home decor and gardening. She covers a range of topics, from practical advice to interior and garden design.