House Plant Care: the 7 Critical Requirements

House plant care basics: the 7 requirements

If you can master these house plant care basics, you’ll find that you are in a pretty good position to look after most kinds of house plants.

All plants have various requirements that need to be met in order for the plant to thrive and grow. For house plants, the 7 critical requirements relate to: light, water, nutrients, warmth, humidity, dormancy, and leaf and stem maintenance. The basic principles of house plant care involve adjusting how we meet these requirements, on an ongoing basis, to suit the particular plant you are caring for.

But when making these adjustments to take care of your plants, it is critical to remember that too much of a particular input will be just as damaging for an indoor plant as too little of it. A house plant is just as likely to die from too much water, for example, as it is from too little water.

I’ve been gardening and keeping house plants for nearly 25 years now and have learned a few lessons along the way. The biggest lesson is that it is probably harder to take care of your indoor plants than it is to take care of your outdoor plants. 

There are very few desirable house plants that can be neglected and there is no virtually such thing as low maintenance plant when it comes to houseplant care. Some might say the zz plant, the spider plant or the snake plant are exceptions, although I don’t entirely agree. In any case, the point is that indoors is an alien environment for plants, so they need our help to grow and thrive.

Therefore, it is important to understand the house plant care basics. This will help you look after your plants, keep them at their healthiest, and enjoy the life and beauty they bring to your home.

So this post is house plant care 101: house plant care for beginners or for those who have had their indoor plants for a while but have struggled to keep them happy.

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Outdoor vs indoor plant care maintenance

We have established that the house plant care basics are all about adjusting the inputs that are required to meet a plant’s needs. However, one of the biggest challenges we have when caring for house plants, is that the different types of house plants that we grow have different needs. And those needs are dictated by the conditions the plant would have experienced in its natural habitat in the wild.

When we raise plants in our gardens, we try to make sure that, as closely as possible, the conditions in which we grow different plants match the conditions the plant would be growing in naturally. Thus, we need to make sure that tender plants are protected from frost or only grown as summer annuals; we place shade loving plants in a shady spot; and we ensure that succulent or other sun loving plants are planted in the sunniest position in our gardens.

The same principles apply with house plants, except we need to bear in mind that the starting point with indoor plants is that indoors is an entirely artificial environment as far as plants are concerned.

Indoors, the plants’ needs cannot be met naturally. There is no rain, no natural soil with its store of nutrients renewed by organic matter, no wind, no high levels of light, and no natural humidity.

Instead, the indoor environment is generally characterised by low levels of natural light and artificial heating, which dries out the air and compost that we try to grow our plants in.

So, there is no simple indoor plant care and maintenance blueprint that fits all plants. However, we can take care of our house plants’s basic needs once we know how. What we need to do is: understand the particular requirements that our plants have and adjust those to take into account the artificial indoor environment that we are growing our plants in. That is the key principle of houseplant basics.

House plant care basics: meeting the needs of indoor plants

It is worth developing this point about the artificiality of the indoor plant environment a bit further, because it is critical to our understanding here.

If you think about it, plants evolve to thrive in the conditions in which they naturally occur. Cacti thrive in the searing hot days and freezing nights of the deserts, bromeliads thrive in in the humidity of rain forest trees, and ferns thrive in the damp shade of cool woodlands.

Yet it is possible for us to try to grow all three of these types of plants in the one environment – our home. It is also perfectly possible to succeed in this seemingly hopeless endeavour. And the key to our success is to understand the requirements of the plants and how we can adjust conditions and our plant care regimes, as far as possible, to help them thrive.

Below we look at each of the key requirements for successful house plant care in turn.

Light

Plants need light to photosynthesise, which is the basic process by which they convert nutrients and water into the energy that enables them to stay alive and grow. But, the intensity of light that a plant needs varies according to the type of plant. 

In general, most cacti, succulents and flowering plants require more direct sunlight than the plants that we grow mainly for foliage.

The plants we grow for foliage are often tropical houseplants, many of which would grow in the lower storeys of the rain forest. Therefore, they naturally receive lower levels of sunlight.

So when it comes to caring for the cacti, succulents and flowering plants as indoor plants, they can be placed where they receive more sunlight, more of the time, e.g. near a sunny window. The foliage plants (the typically tropical plant) can be placed where they receive indirect light, in other words not in direct light from the sun. 

These are general rules and there are some exceptions. For example, flowering plants should often be moved out of the direct sunlight when they have finished flowering, and some plants, Sansevieria (snake plant), for example, can cope with both bright light and low light. 

It is also worth pointing out that most plants generally need daylight for longer periods (typically 12 to 16 hours) in order to induce active growth. This is why plants begin to grow in Spring when day lengths increase.  When there are fewer hours of sufficiently bright light, the plant’s growth stops and its metabolism slows down. There is more on this under the heading of dormancy below.

Water

One of the first house plants I ever bought was a shooting coconut plant (Cocos nucifera) from Ikea. I was thrilled with the exotic look of the plant, especially as the coconut itself was intact in the pot. However, in only a few weeks, the plant was dead. I know now that Coconut plants raised in hot houses are notoriously difficult to transition to the home environment. So the plant’s untimely death was probably not entirely my fault.

However, I’m pretty sure I hastened the poor plant’s demise because, as it began to look unhealthy, my response was to give it more and more water. And that was entirely the wrong thing to do. If you think about it, coconut palms grow on the sandy fringes of hot beaches, There, because of the sand, the soil is very free draining and watering by rain is infrequent for a lot of the year. So, it follows that what the plant needed in its hour of need was less water – not more.

So when it comes to the watering needs of our house plants, we need to remember that whilst all plants need water, the roots of our plants also need air. So, apart from a few ‘always wet’ plants, we generally need make sure that we don’t overwater, so that the plant’s roots do not become waterlogged in the potting mix and so that we don’t get infestations of fungus gnats, which thrive in over-wet soil.

The amount and frequency of water needed varies from plant to plant and also varies according to the size of the plant, the environment and the time of year. But here are some basic principles:

• Check the watering needs of your particular plant.
• Water when the plant needs it – not in accordance with some routine that suits you.
• Observe your plant – do the leaves look a bit shrivelled or curled? How wet or dry does the compost look?
• Feel – dip your finger an inch or so below the surface of the compost. If it is dry at that level, water.
• Be prepared to water more in the growing season – spring and summer.
• Water less frequently during the plant’s dormant period in winter

Nutrients (food)

In order to grow, plants need Nitrogen (N), Phosphorous (P) and Potash/Potassium (K), plus a variety of trace elements and minerals.

The main nutrients each promote the following different aspects of growth in growing plants:

• Nitrogen – promotes the growth of leaves and stems;
• Phosphorous – encourages root growth; and 
• Potassium – promotes flowering and fruit.

Although we fertilise our garden plants, usually with a balanced feed containing the right proportion of nutrients, nutrients do exist naturally in the soil. Garden plants can therefore draw on these nutrients by extending out their roots to take in what they need.

Plants in pots have to rely on the nutrients in the potting soil in which they are planted. Once the plant has used all those nutrients up – usually in about 6 to 8 weeks –  it doesn’t have the option to spread its roots into fresh soil. Hence, feeding our indoor plants is essential.

House plant fertilisers will normally contain a balanced mix of the nutrients that plants need. Granular and powdered fertiliser mixes are less efficient for indoor plants than they are for outdoor plants, where they can be washed down into the soil by rain. So, the best option for houseplants is to fertilise with liquid feed mixed with the water you give your plant at watering time. Make sure you follow the instructions on dilution rates on the bottle or packaging.

Taking this approach means that you will be applying plant food at regular intervals at the right time.

Your house plants only need to be fed during their growing season. This is spring and summer for most plants, but autumn and winter if you have a winter flowering plant. Stop, or significantly reduce feeding during the dormancy period.

There are some clues that our plants can give us about feeding, which will help you understand your plants’ needs better.

Signs that more fertiliser is needed are:

• Slow and/or weak new growth;
• Lack or flowers, or weak or poorly coloured flowers;
• Yellowing of the leaves, including yellow spotting
• Pale leaves;
• Greater susceptibility to pests and diseases.

Signs of over-feeding are:

• Scorched looking leaves, especially at the edges
• Poor summer growth
• Weak and leggy new growth
• Drooping, or wilted leaves
• White deposit on the surface of the compost.

Warmth

As a general rule, most house plants will grow reasonably well in temperatures between 13° to 24° Celsius or 55° to 75° Fahrenheit.

Even plants used to higher temperatures in nature will not thrive indoors in normal conditions above 75°/24° indoors because of the lower light levels and lack of humidity.

Ideally, you should try to provide lower temperatures during periods of dormancy. Admittedly, this is not always easy since, for most plants, the non-growing period coincides with when when we most need to heat our homes. However, moving plants to less intensively heated rooms can be beneficial.

Plants also prefer a night time drop in temperature of around 10°F or 5°C. But the main thing to avoid, daytime or night time, is a sudden, large fluctuation in temperature

Of course, as ever, different plants have different requirements. So you need to check the temperature guidelines for your plant. But in general:

• The most tender plants need a minimum temperature of 60°F (15.5°C);
• Other non-hardy plants need a minimum temperature of 50° to 55°F (10° to 13°C;
• Hardy plants need a minimum temperature of 40° to 45°F (5° to 7°C).

Humidity

Most of the plants we grow as house plants (other than the cacti and succulents) originate from tropical regions with naturally high humidity. Centrally heated indoor environments are very dry, with very low humidity. This means that, for much of the time, the humidity conditions inside our homes do not suit our indoor plants – and it is the plants with thinner leaves that are most affected.

Therefore, in winter when we are heating our homes, we need to take some action to alter conditions to suit our house plants.

One option is to move some plants into the more humid spaces in our homes, such as kitchens or bathrooms.

Where this is not possible, we can take steps to modify the humidity levels around our house plants. There are various ways we can do this. For example, we can:

• Regularly mist the leaves of the plants;
• Arrange the plants closely in groups, or 
• Place the plants on a shallow tray filled with gravel that we keep topped up with water. 

Signs to look out for that suggest there is too little humidity for your plants include:

• Brown and/or shrivelled leaf tips;
• Wilting leaves;
• Yellow leaf edges; or
• Leaves falling off the plant.

Dormancy (rest period)

When we are growing houseplants, it is easy to think that the warm environment and plentiful water and nutrients that we can provide our plants means that they can grow all year round.  But, as we have established in the section above about light, indoor gardening is not that simple.

Plants need a minimum number of daylight hours in order to actively grow. Once the amount of daylight hours drops in winter then most plants will cease growing. Consequently the need for water and nutrients reduces and the plant enters a period of dormancy.

We need to respect these reduced demands and reduce the amount of feeding we do and cease frequent watering. Otherwise, the plants will suffer. In practice this means no feeding is usually required and watering should take place only when the soil moisture has disappeared completely and the soil mix is dry. 

The exception to this rule is the winter flowering plants. As they get ready to flower they are still in active growth, so normal routines should be maintained until flowering has finished. It is at that point that dormancy sets in and feeding and watering should be reduced.

As day length increases in Spring, you should see signs of growth from you plants and it is at that point you can increase the frequency of feeding and watering again.

Leaf and stem maintenance

Trim dead leaves

People are often concerned that if houseplant leaves turn brown there is something wrong with the plant. That may be true, but in most cases it probably isn’t. 

Evergreen plants, like ficus, don’t live for ever with the same leaves on them. There is a constant process of renewal – old leaves die off and new leaves grow. Similarly, some plants like Strelizia, Alocasia and many palms grow new leaves from a central growing point. As the plant gets bigger, the older, outer leaves gradually detach from the plant’s feeding systems and die off. 

This is why you may well see an indoor plant with some nice healthy growth on it but also a whole lot of brown or shrivelled leaves as well. 

It is also why the first rule of plant maintenance, as far as I am concerned is this: cut off the dead and dying leaves from you plant. The plant will look much better and if there is a problem with the plant it is much better to remove any diseased foliage than to leave it on the plant. 

Clean the plant’s leaves

All plants gather dust. But, there is no rain or wind indoors to keep the plant fresh and clean, as is the case in the wild. This is therfore something we have to take care of on the plant’s behalf.

It is critical to remove the dust from your plants’ leaves for a couple of reasons. Firstly, dust blocks the pores on the leaf surfaces, so the plant cannot take in carbon dioxide and expel oxygen and water vapour. These are vital aspects of the process of photosynthesis. 

Dust also blocks light from entering the cells and chloroplasts inside the plants’ leaves. This interferes with its ability to take in light and convert it to energy. Again, this is vital for the plant to remain healthy and grow.

Therefore, we need to keep our house plant’s leaves clean. Here is how:

• Use a soft brush to dust off the leaves first. This is also the best way to clean cacti or succulents that have spikes or hairy leaves;
• Small plants can be plunged in water and left to drain;
• Use a water spray on plants with small leaves, shaking off the excess;  
• For larger leafed plants, spray the leaves and then sponge off the dirty residue on the surface, supporting the back of the leaf with your hand.

It is best to do this early in the day, so that the plant can dry off by night time.  

If you have access to outdoor space, then in the summer time, you can take your plants outside and spray them down with a hose.  The plants look so much better after you’ve done this, it almost seems like the soaking reinvigorates them, just like taking a shower can do for us. 

However, before you give your plants a shower, make sure there is not a significant temperature difference between outside and inside. Otherwise the plant will suffer a shock. Also, do this job in the shade, so that they are not suddenly scorched by bright light or hot sun.

Conclusion

Looking after the house plant care basics is key to  your success with house plants. If you can meet your plants’ requirements for light, water, food, warmth, humidity, dormancy and maintenance, you’ll have happy house plants and a happy house plant grower.

House plant care basics: key references and resources

Alloway, Z and Bailey (F). (2018) RHS Practical House Plant Book: Choose The Best, Display Creatively, Nurture and Care, Royal Horticultural Society, UK.

Camilleri,L and Kaplan, S. (2020), Plantopedia: The Definitive Guide to Houseplants, Smith Street Books.

Hessayon, Dr D.G. (1991) The New House Plant Expert, PBI Publications, UK.

Squire, D. (2017). Houseplant Handbook: Basic Growing Techniques and a Directory of 300 Everyday Houseplants, CompanionHouse Books.