We may live in a world that considers itself pioneering in terms of health and wellbeing, however, an increasingly popular tool in ensuring good health has surprisingly been present for over 3,000 years. This consists of the house plant; commonly recognised as a plant that will successfully flourish indoors- particularly in homes and offices.
Initially adopted by Chinese cultures to pursue gardening interests when the weather became overly harsh, and often used to signify wealth, house plants have been appreciated by humans for thousands of years. Whilst some individuals quite understandably commend house plants for their historical significance, we have become increasingly conscious of their health benefits. Namely, these are their ability to improve breathing, mitigate the risks of illness, reduce anxiety and blood pressure, enhance productivity, and perhaps most impressively, purify the air within our homes.
Throughout this post, we will specifically detail how a house plant purifies the air, we will also suggest our favourite ones for doing so, and answer any common questions that you might have.
A Plant’s Air-Purifying Abilities
A house plant will clean the air within your home by absorbing harmful gases through both their leaves and roots. Their soil will additionally neutralise volatile organic compounds (these include the common household pollutants of benzene and formaldehyde). It is these purifying abilities that are utilised most profoundly in phytoremediation; a process where plants will remove, contain, or destroy environmental contaminants. This process isn’t merely applicable to air, but additionally to polluted water and soil.
Both benzene and formaldehyde are volatile organic compounds that are prevalent within the home. Benzene can be found in certain plastics, pesticides and cigarette smoke, and formaldehyde can be present within cosmetics and various cleaning products. To help ensure a safe and healthy environment for you and your loved ones, we have detailed three house plants deemed excellent in removing these harmful pollutants from the air.
Air-Purifying House Plants: Our Three Favourites
Peace Lily:The perfect means of adding a simplistic, graceful touch to your home, a Peace Lily is an esteemed air purifier. Also referred to as Spathiphyllums, Peace Lilies will successfully remove carbon monoxide, benzene, formaldehyde, trichloroethylene, and xylene.
Spider Plant: Valued for removing both formaldehyde and benzene from the air around us, a Spider Plant will also prove a low-maintenance option for your home. Importantly, it has been evidenced by NASA that a Spider Plant can remove approximately 90% of formaldehyde nearby. If you wish to order one of these wonderful Spider Plants, they can be found here.
Boston Fern: Displaying charmingly disheveled foliage, a Boston Fern is another wonderful house plant for reducing the pollutants within your home. To ensure that your fern flourishes, we encourage you to keep it away from direct sunlight, and to water frequently.
Commonly Asked Questions
My home doesn’t experience much light, is there still an air-purifying house plant for me?
There certainly exists a perfect air-purifying house plant for every home and environment. We advise that the most suitable house plants for areas experiencing low-light are Devil’s Ivy, Maidenhair Ferns, Leopard Lilies, and Lucky Bamboos.
I have a cat and a dog, can I still have an air-purifying house plant in my home?
Again, both the Spider Plant and Boston Fern consist of air-purifying house plants believed harmless for cats and dogs (other animal-friendly house plants are Orchids and Peperomias). Nevertheless, to prevent your beloved pets from chewing or playing with your plants, we advise you to place them in windows, or towards the top of a shelf.
What is the best air-purifying house plant for the bedroom?
The addition of a house plant within your bedroom is an excellent way to create a peaceful, yet also lively sanctuary. A rubber plant is great for adding interest and structure to an emptier room, whilst a ‘Million Flowers’ Anthurium will add a colourful touch to your bedroom’s window sill.
Keeping house plants is a fun and rewarding hobby that can bring a host of benefits to you and your home. It may seem like there are lots of things to consider when starting out with indoor plants but actually, following a few simple rules will work wonders. Read on to discover our easy care guide.
Identify your house plant
The first thing you have to do is identify your plant. This should be made clear to you on purchase but for plants which are gifted to you or that you’ve inherited, the internet is going to be your best friend here. There are many plant ID apps that can recognise your plant from photos so this can be a quick and easy way to find a match. You can also communicate in online forums like the Houseplant section of Reddit to try and get an ID – this is also a great way of getting involved with a community of enthusiasts!
Once you’ve successfully got the name of your house plant you can familiarise yourself with what it needs. There is a tonne of information out there to get lost in but you can focus on just two key things when setting up; light and water. Get these two elements right from the start and you’ll have a healthy and lush plant.
Light
All plants require light in order to kickstart photosynthesis. The process where sunlight is converted into sugars to aid the healthy growth of the plant. The main thing you need to concern yourself with is the amount of light that your house plant requires. A Yucca plant, for example, will love basking in bright sunlight for the majority of the day whereas some Calathea plants prefer to spend their days in the shade.
We use terms like direct light, bright indirect and filtered light to describe the differences in light around our homes and this is your best indicator for where to place your plant. Take a look at the infographic below to see the typical breakdown of light levels
Water
Water is essential for a healthy plant and you’ll be glad to know that house plants are actually pretty good at telling us when they need water, we just need to know what to look out for.
Check Your Soil
Your first and best way to see if your plant needs watering is to check the soil. Push your finger into the top layer of soil – what do you feel? If it’s still wet you can hold off watering; if it’s damp you can maybe top up with a little water; if it’s totally dry it will probably benefit from a drink.
It’s much better to check your plants regularly and respond rather than watering to a strict schedule. Remember though that different plants will have different requirements. With a Snake plant its okay to let the top inch or so dry out completely between waterings but we shouldn’t do this with a Fern which should be kept relatively damp at all times. These distinctions will be made clear on the Primrose website when purchasing your plant.
Check The Leaves
Other things to look out for are the activity of the leaves. If they are dry and curling at the edges this can be a sign of needing water. Some plants like the Peace Lilly will droop its leaves when in need of a drink and they’ll spring back up again once they’ve been watered! If your plant’s leaves begin to yellow and droop than this could be a sign of overwatering and you should hold off for a while to let it recover.
Golden Rules Of Watering:
Here are just a few simple rules that will put you in good stead when watering your plants.
Always check the top level of the soil to see if your plant needs watering again.
Never let your plant sit in water. Allow water to run through the soil, out of the base of the pot and drain away before returning it to a display pot.
Try and get close to the conditions of its natural environment; a cactus will want to be kept dry but a monstera can appreciate some moisture.
Too little water is easier to deal with than too much water. Remember that it’s much quicker to kill a plant with over-watering than it is from forgetting to water occasionally.
If you are concerned about remembering to water your plants than you can always purchase a houseplant that can stand a little neglect. Many varieties such as the snake plant, yucca, aloe vera and more are pretty drought resistant, meaning they’ll forgive the times when we forget to water them and survive without too much help from us.
Below are some other considerations that you can take into account when looking after your plant. These bits are good to know but remember, as long as you have the light and water right you and your plant will do just fine.
Humidity
The easiest way to get the right humidity for your plant is to think of its natural environment. If it comes from dry desert locations then you’ll want to avoid placing it in a room where the air is full of water such as the bathroom. But if you have a plant that comes from tropical regions such as an orchid, then the bathroom can be ideal. Some plants like the monstera will prefer an increase in humidity only when temperatures begin to rise and this is easily addressed with a spray bottle of water.
Food
The majority of nutrients that your plant receives will be taken up from the soil they are potted in. It’s good to replenish this or give an extra boost during the growing seasons and one of the best ways to do this is with a plant feed. This is usually sold as a liquid fertilizer that can be diluted in water. It provides an extra hit of all the nutrients your plant needs and you’ll see the effects coming through in better-coloured leaves, more abundant flowers or extra spurts of new growth. Always follow the instructions when using fertiliser and remember that using it once in a while will have better results than using it constantly.
Potting Up
You’ll soon encounter the phrase “potting up” when you start keeping house plants. This simply means transferring your house plant from its current pot to a bigger one to give it extra room to grow into. You won’t have to do this very often. One of the obvious signs a plant may need potting up is if you find it “root bound” which simply means when the roots of the plant have run out of space and begun pushing out of the bottom of the pot. You may even take it out of the pot to see the roots have bound themselves into tight circles.
Scott is a copywriter currently making content for the Primrose site and blog. When at his desk he’s thinking of new ways to describe a garden bench. Away from his desk he’s either looking at photos of dogs or worrying about the environment. He does nothing else, just those two things.
A number of studies are linking time spent in nature to better health and wellbeing. Our gardens are one of the easiest ways to get some quality time outside. If you live in a flat or within a city however you may find your own outside space lacking. One of the easiest ways to bring nature back into your home is with house plants.
The trend for potting up nature has created a huge increase in the number of house plants available to us. There’s never been a better time to start keeping indoor plants, whatever your level of expertise. We’ve handpicked 3 of our best indoor plants for beginners so you can start bringing nature back into your home.
When shopping for house plants you quickly discover their many names. We can introduce our first plant as the Snake Plant, Saint Georges Sword, the Mother in Laws Tongue or its Latin name, Sanseveria. Whatever you decide to call it, there are plenty of reasons for having this as your go-to house plant.
It’s (almost) impossible to get wrong. If you’re a serial plant killer than the snake plant is an excellent way of putting some house plant success on your record. They can survive in many different levels of light so can be placed anywhere in your home. They’re also very drought tolerant which means they’re very forgiving if you forget to water them.
They can help you sleep. They are one of the few house plants to give off oxygen primarily at night. This makes them well suited for bedrooms where the fresh oxygen can contribute towards a good nights sleep. NASA has even named them as one of the top air-purifying plants.
Beautiful leaves. Though there are many kinds of Sanseveria that have a variety of shapes and colours; what makes the leaves of these particular snake plants so attractive is their variegated leaves. Variegation is just a fancy way of describing the light and dark ripple patterns on the leaves. Variegated leaves add extra character to all sorts of plants but the snake plant remains one of our all-time favourites.
Used in a variety of hand-gels, shampoos and cosmetic products, the Aloe Vera is a plant many of us will have heard of before. Aloe plants have a long history of being used as a traditional home remedy. Combined with how easy they are to grow this house plant is a sure winner for anyone starting out in keeping plants indoors.
Easy to grow. The Aloe Vera is another hardy indoor plant which can get along just fine with little help from us. It’s a succulent so can store lots of water in its leaves, making it like the snake plant, fairly drought resistant. You can feel an aloe has plenty of water when the leaves maintain a firm but fleshy texture.
A home remedy. Few house plants can boast of being able to help you in as many ways as the aloe vera. It’s been used for everything from soothing minor cuts and burns to clearing up acne. And on top of all that, it joins the snake plant on NASA’s list of top air-purifying house plants!
Interesting shape. Among succulents and among house plants generally, these plants have very distinctive foliage that can add a bold focal point wherever you place it. They make great companions for your sansevieria whose leaves follow a similar shape.
The humble Monstera Deliciosa is one of our best large house plants. With leaves that slowly unfurl and darken in colour, perforations that appear on each leaf and the far-reaching shape that can fill just about any space, you’ll find plenty of reasons for loving this most popular plant.
Unique foliage. The leaves of the monstera are what makes this plant so recognisable. The distinctive holes earn it the nickname “swiss cheese plant” and it’s been a popular indoor plant for decades.
Easy to grow. A monstera can quickly fill out any space. Its easily maintained and vigorous growth is one reason why its a favourite for decorating our interiors. They make great moving in gifts thanks to this and their traditional associations with good luck.
Can be trained. The only thing better than a house plant is a house plant that can be styled. The fast growth of the monstera makes it easy to control the overall shape of your plant. Moss poles are usually used to direct growth upwards, otherwise, you can let nature run free and have leaves shooting in all directions.
Most house plants require very little attention, with regular, but infrequent, watering and annual or biennial repotting.
Watering & Humidity Requirements
The key is not to overwater as to cause root rot and plant death. Watering when soil is dry, or almost dry, is a good rule of thumb. It’s important to push your finger into the soil to check for moisture, as soil may appear dry but be wet underneath.
It’s surprising how long certain species can survive without water. Succulents, of course, have various morphological characteristics that allow them to store water and reduce transpiration.
You may remember epiphytes from biology class, such as lichens, which are not a single organism, but two in a symbiotic relationship. Epiphytes grow on the surface of other plants, and most do not root in soil. Instead, they absorb water from the air. Some species of orchid, including the popular Phalaenopsis, are epiphytes. One egregious example, such as some species of Tillandsia, also known as the air plant, have minimal root systems and grow on shifting desert soil.
Even houseplants that do root in soil, such as Zamioculcas, most are drought resistant. If you are ever unsure about a plant’s watering requirements, first check a supplier’s website. You can also make assumptions based off a plant’s climate. Species from rainforests benefit from high humidity, and those from deserts low. Also, what morphological characteristics does the plant possess? A plant with lots of thin leaves will lose water faster than one with thick, leathery, waxy, or hairy leaves, and one with no leaves at all.
You can tell when a plant is suffering from too little water as it will first droop and then wilt. Don’t give up. Just because a plant is wilting doesn’t mean it can’t be revived. All that is happening is that the cells have depressed and the plant become slack. When watered, its cells fill up and the plant becomes taut. So, give it a thorough watering and watch it spring to life.
Plants in small pots (succulents excluded) do need monitoring as small pots have a tendency to dry quickly. It’s best to repot and when you do, ensure you don’t compress the soil. Otherwise, the soil is liable to becoming waterlogged.
Plants can die from insufficient watering and it’s usually because of gas embolism. Normally, plants absorb water through its roots, which travels up through the stems to the leaves. In times of drought, plants will sometimes absorb air that can form a bubble, which blocks the flow of water upwards.
Certain species, especially those from rainforests, benefit from high humidity. Humidity is important as the lower the humidity, the more water is lost to evaporation. Temperature affects the amount of water air can hold, so more water is lost at higher temperatures.
Greenhouses are low humidity and perfect for cacti.
Humidity can temporarily be increased by misting – spraying plants with water. Preferable, is putting plants on a drip tray covered in pebbles and filling the tray with water, which will evaporate at room temperature, creating a nice microclimate for your plant. If you drill a hole in your pot, it will help with drainage, and excess water will fill the tray anyway. You can also try grouping plants together and planting plants in terrariums, from which water can’t escape.
You can measure humidity by purchasing a thermo-hygrometer, which measures relative humidity. It will give a reading in as a %, because at say 75% relative humidity, the air can hold 25% more water at the same temperature. Once you have worked out each room’s humidity, you can put your plants in the room they are best suited.
You can tell when a plant is suffering from low humidity as it’s leaves will begin to curl, as to reduce the surface area exposed to light. Plants are unlikely to suffer from high humidity, but from pests and diseases that multiply in conditions of high humidity.
Light Requirements
Plants need light to kickstart photosynthesis – a process whereby sunlight, water and carbon dioxide is converted into glucose and oxygen. Glucose is used by the plant in numerous key functions such as metabolism and growth, and is also stored as starch.
Most house plants are well suited to poor lighting and will suffice in substandard conditions. However, it’s best to reserve bright rooms for plants selected for flowering, fruiting or variegated foliage, as these processes will overwise be inhibited.
Certain species are sensitive to sunlight hours. Some will only flower when the days are long and others when the days are short. Keeping these plants near windows, and away from artificial lights will help with flowering. Others are day neutral, unaffected by day length.
Poinsettias are one fascinating example of photoperiodism – the response of an organism to day length. The species has evolved to cease the production of chlorophyll and initiate the production of anthocyanins in response to shortening days, resulting in its leaves going from green to red, in the aim to attract pollinators to its tiny flowers. You can initiate this transformation yourself by putting the plant in total darkness for 3 months 14 hours a day.
It’s important to give your plants a period of darkness (at least 8 hours). At night, plants respire, taking in gases used in photosynthesis in the day, and also break down glucose produced in the day in maintenance and growth. (In the day, plants close their openings to reduce water loss. Hence, while plants produce energy in the day, they use it at night.)
Certain species, such as many epiphytes, aren’t adapted to direct sunlight and may pale, brown and die from too much exposure. Simply, move to a darker location.
Plants do not absorb all wavelengths of light equally, with the main pigments involved in photosynthesis (chlorophyll) primarily absorbing blue and red light with green reflected. (This is why plants appear green to your eyes.)
Artificial lighting can be absorbed by plants, but is composed of different wavelengths than natural light. Incandescent lighting produces mostly red light, while fluorescent and LED light varies. LED lights are often divided into cool and warm variants, with the cool emitting more blue and warm more red.
You can grow plants exclusively under artificial light, say in a basement, but it’s important to get the colour balance right, otherwise flowering, variegation and growth will be affected.
High intensity blue light will promote the flowering of long day plants and inhibit that of short day plants. Likewise, even low intensities of red light exposure at night will inhibit the flowering of short day plants and promote the flowering of long day plants.
Blue light is important in promoting leaf colouration. Varieties with purple leaves may go green in its absence. A dearth of red light will result in spindly growth and a dearth of blue light stumpy growth.
Light intensity decreases as the distance from the source increases. It is for this reason window direction affects the intensity of natural light received. Windows facing east and west receive about 60% of the intensity of southern exposure. Northern exposure a mere 20% of southern exposure.
A room’s light intensity is affected by the colour of a room’s surfaces (with lighter colours reflecting light and producing brighter rooms), and the transmission of natural light, whether it’s blocked by outside objects, curtains/blinds or dirt on windows.
Often blinds are closed and curtains drawn in the day, but don’t forget your plants need light.
Light intensity varies throughout the seasons. In summer, window sills are bathed in light, as the sun rises quickly and is mostly high in the sky. In winter, natural light actually penetrates interiors further as the sun stays low in the sky.
Insufficient sunlight leads to etiolation, whereby a plant grows spindly with long gaps between nodes – areas of the stem where leaves are located – and chlorosis, whereby leaves turn yellow, caused by the death of chlorophyll. Both these effects make evolutionary sense, allowing the plant to stretch in search light and forgo wasting energy on useless leaves.
It is possible to measure light levels, but you’ll need a camera. The process is detailed here.
Temperature
Temperature speeds up respiration, causing plants to break down glucose faster. Glucose is produced from photosynthesis, which is a function of light intensity, duration and composition.
First, glucose is used in maintenance and then, if there is some spare, growth. Hence, growth increases with more light and higher temperatures, and slows with less light and lower temperatures.
If a plant has insufficient glucose for maintenance, it’s cells break down and it eventually dies. To combat this, you can either raise light levels to increase glucose production or reduce night time temperatures to reduce glucose consumption.
Cooler night time temperatures benefit many plants, as it is in this period they exchange gases and release water. If temperatures are too high, a plant may fail to open its pores, causing it to suffocate/overheat. Switching your heating off at night will benefit most plants.
House plants from tropical and subtropical climates, where there are small variations in day/night temperatures, and equatorial climates, where there is no seasonal fluctuations, but not those from deserts, where the nights are very cold, are liable to chilling injury. These plants are simply not adapted to low temperatures and can’t change their respiration rates.
Spraying your tropicals with cold water can send them into shock.
Sudden exposure to cold is worse than gradual and can lead to rapid chilling injury, so try to keep temperatures consistent. Keep your plants away from draughts and place in rooms where temperatures fluctuate the least. Don’t water tropicals with cold water.
Nutrition
Nutrition is important, but if you have a problem with your plant, it’s likely down to sub-optimal lighting, humidity, watering, or temperature.
Diagnosing nutrient deficiencies from visual examination is challenging and soil testing is necessary for certainty. There are five symptoms caused by nutrient deficiencies: stunted growth, chlorosis (yellowing of the leaves), interveinal chlorosis, purple-red colouring and necrosis, although these are also caused by other factors including nutrient toxicity.
The development of symptoms help rule out certain factors. Some nutrients are immobile and can’t travel from old to new growth, while others can. Thus, if the symptoms are localised, it will be an immobile nutrient, but generalised a mobile one. Montana University have developed a useful identification key from such information, on pages 6 and 7.
Watering with tap water can lead to a buildup of salts.
Just like with watering, you can over-fertilise, as so nutrients become toxic. Build up appears as a whitish crust on the soil’s surface and around the rim of the container. (Watering with tap water will cause this also.) To remedy, flush the soil by gently watering, ensuring water flows out of the bottom. Like with deficiencies, the symptoms of toxicity are examined on page 13.
Due to the complexities of diagnosing nutrient deficiencies, it’s best to follow rules of thumb. For example, if you want to grow your plant, you’ll want to apply fertiliser, but also put in a well lit area, as plants produce most of their energy from photosynthesis. Vice versa plants in well lit areas will need fertilisation.
You’ll want to apply fertiliser in or before the growing season, depending on whether or not the fertiliser is slow release. During or before dormancy, fertiliser is unnecessary. Fertilisation should be based on the amount of soil and size of the pot and the species. Fertilising slow growing succulents is unnecessary, but is useful for fruit maturation (i.e. with chillies). Fertilise after watering and never before, as water will wash away nutrients, but is necessary, as most nutrients absorbed is dissolved.
Repotting
Key is not to compact the soil as compaction will stop air and moisture reaching plants’ roots. Contrary to popular belief, you don’t need specialist compost, although it’s preferable. Different materials exert different effects on plants. Terracotta is famously porous and drains faster than non-porous materials. Recently, I planted my chillies in a mix of terracotta and plastic pots, and made the mistake of watering them at the same time. The terracotta pots’ soil would be bone dry and the plastic pots’ moist.
Acclimatisation
Every plant will adapt to its conditions, but adaptation takes time. Commonly, house plants are moved outside in the summer months, put on a flush of growth, and are then moved back indoors, and start to drop leaves. The plant simply can’t produce the energy to support the sun leaves and will produce less energy intensive shade leaves. Changing light levels is rarely fatal, but changes in temperature is. Outside winter temperatures are too low for many house plants, so ensure you house doesn’t get too cold.
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Jorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!
His ideal afternoon would involve a long walk, before settling down for scones.
Jorge is a journeyman gardener with experience in growing crops.
Scott is a copywriter currently making content for the Primrose site and blog. When at his desk he’s thinking of new ways to describe a garden bench. Away from his desk he’s either looking at photos of dogs or worrying about the environment. He does nothing else, just those two things.
Jorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!