Plants have a unique life cycle—they can die down, come back, and grow endlessly. It’s certainly not similar to what we see in humans or animals, so what dictates how long plants live? Is it possible for a houseplant to live forever?
Houseplants could live forever. They don’t die of “old age” the way humans and animals do. The oldest known plant has lived for 4,500 years. However, practically speaking, most houseplants won’t live over a decade because of suboptimal environmental conditions, poor care, or disease.
In this article, I’ll share the slightly complex but interesting science that governs how long plants live. I’ll also discuss how to use this information to ensure your houseplants stay healthier and live longer.
How Long Do Houseplants Typically Live?
Getting your very first houseplants can be an interesting prospect. They make excellent indoor decorations and liven up the atmosphere.
Not only that, but houseplants also improve the air quality by a small amount, so there’s some tangible benefit for you.
However, you may be wondering how long your first set of houseplants will last and when you’ll have to replace them. This completely depends on how well you’ll care for them. The variance in lifespans for houseplants is immense.
For example, you could have a houseplant die in mere months if you overwater it. Another houseplant of the same species could live for decades if it’s well taken care of.
If you would prefer a statistic, most houseplants live for two to five years, but I don’t think you should be satisfied with having your houseplants live to that age.
See, houseplants (and all plants in general) can live much longer under the right conditions.
Why Don’t Houseplants Die of Old Age?
What exactly does it mean to die of old age?
Well, as we age, our cells lose the ability to divide and regrow. This is called cell senescence.
Therefore, we get weaker. We heal slower, our health worsens, organ and organ system function declines, and we become more susceptible to illness, injury, disease, and infection—just about anything that wants to kill us.
What we really mean when we talk about a person dying of “old age” is that they failed to survive an ailment or illness that they would have had far better odds at surviving if they were younger. When their cell division and, therefore, organ function and regenerative ability were at their peak.
Things are different when it comes to plants. See, plant cells don’t lose their ability to divide. In particular, stem cells found in the meristem of plants can divide indefinitely.
Because of these endlessly dividing stem cells, you can grow a full plant from a single root or leaf. Fascinating, right?
As a result, there’s little to no gradual worsening of health that would cause a plant to be more susceptible to an external damaging condition later down the line than it is now.
Plants (especially houseplants) never die of old age. They die due to damaging conditions.
Admittedly, cell senescence is still not a fully understood concept. It’s one of the most perplexing topics in biology. But we do know that many plants show little to no senescence in their meristem.
Remember that many plants will still show senescence in their leaves and flowers seasonally, which is why we have annuals, biennials, and perennials. However, their roots don’t lose their ability to grow and produce more cells.
And so, perennials that lose their foliage during winter simply grow back up next year.
Annuals and biennials can simply be brought indoors and overwintered, and they’ll live. It’s not cell senescence that kills them, it’s just the sheer winter cold.
Can a Plant Keep Growing Forever?
If plants have cells that can divide endlessly, does this mean they just keep growing larger forever?
Plant growth usually ends up being bottlenecked by their food and water requirements.
The bigger a plant grows, the more food and water it needs. And it would have to work increasingly hard to transport said food and water around its body. That’s the case for most standard-sized plants, at least.
The oldest known plant to man is a 4,500-year-old seagrass that spans 112 miles (180 km) of the ocean floor!
But, for all intents and purposes, most of your houseplants will likely reach a stable size after they’ve lived for a few years. Slower-growing plants such as staghorn ferns may take decades to reveal their final size.
How to Get Your Houseplants to Live Longer
Earlier in the article, I mentioned that houseplants live, on average, anywhere from two to five years.
This statistic results from the fact that most owners don’t provide their houseplants with perfect care. Even if they do, houseplants are not completely safe from attack by pests and pathogens.
Unintentional watering, fertilization, and positioning mistakes can cause a plant to die quickly or over time. The good news is that if you know what usually kills houseplants, you can more consciously avoid it.
Plants don’t really weaken with age. So by taking proper care of your houseplants and maybe having a bit of luck on your side, you can get your houseplants to live for decades.
Choose the Right Houseplants
The first and simplest way to increase the expected lifespan of your houseplants is to simply get the ones that live longer. Some houseplants are hardy, self-sufficient, and resilient to disease. Others are more fragile and difficult to care for.
If you’re getting houseplants purely for their decorative capacity, I’d recommend going for beginner-friendly, low-maintenance houseplants so you can get used to caring for them.
The pothos and the Chinese money plant are two very hardy and unique-looking plants that make for excellent decorations.
Something you should keep in mind while choosing your houseplants is their ideal hardiness zone. I’d advise against getting houseplants that don’t fall in your region’s hardiness zone, as winter may kill them.
Water Your Houseplants Correctly
One of the most common killers of indoor plants is incorrect watering.
For example, we often overestimate how much water our plants need and overwater them. This can end up killing a healthy plant in a matter of weeks.
Overwatering the plants can end up suffocating their roots, ultimately killing them. Roots in waterlogged soils can’t get oxygen, which causes them to suffocate and die.
Roots are arguably the most sensitive and vital organs of a plant. If they die, there’s no hope for recovery. On the contrary, you could cut off almost all the plant body above the soil, and it would still recover if the roots were healthy.
Underwatering is also common, although it’s less of a direct threat. Plants can stay dehydrated for quite a while before there’s any permanent damage. In fact, many popular houseplants, like succulents, are drought-resistant, making them excellent for people who can’t keep up with their watering schedule.
All things said, if you own a houseplant, it’s important to educate yourself on how to water them correctly.
As a rule of thumb, It’s best to go for a once-a-week watering routine. This works fine for most people, but there’s a lot of room for improvement simply because water requirements differ so much based on temperature, humidity, and soil quality.
A better routine would be one tailored to your houseplants’ needs. Here’s what you should do instead:
- Stick your finger two inches (5 cm) deep into the potting mix.
- If you feel moisture, you can safely wait another day or two before watering.
- If the soil is dry or has little moisture, you can either wait for another day or water immediately.
- Water generously until the excess drains out of the bottom holes and repeat the cycle.
This strategy satisfies all but the thirstiest of plants while eliminating the risk of overwatering. For moisture-loving plants such as ferns and orchids, you can water them before the soil dries out. Just don’t water to the point where there’s stagnant water.
However, for your standard houseplant, letting the upper soil layer (2 inches or 5 cm) dry out a bit between waterings is the way to go.
This eliminates the risk of overwatering—one of the most common killers of houseplants—and encourages your plants to grow their roots deeper into the soil and naturally become more drought-tolerant.
Plants with longer roots can access more of the nutrients and water reserves in their growing media.
Use Containers With Drainage Holes
Using containers with drainage holes is vitally important because it allows excess water to drain from the container.
We’re human, and we make mistakes. Even if you’re very careful with your watering, it’s only a matter of time before you mistakenly give your houseplants a little too much water.
In that case, having a drainage hole can save your plants.
There are a few clever ways to use containers without drainage holes so they don’t sit around unused. For example, you can use containers without drainage holes as cache pots, or external containers, to benefit from their decorative effect.
The inner or main pot should still have drainage holes. You can remove it from the cache pot every time you water your plant and put it back once all the excess water has drained out.
Use Appropriately-Sized Containers
When you first purchase your houseplants, you should transplant them into a pot 1 to 2 inches (2.5 to 5 cm) wider in diameter than the root base of the plant.
Containers that are too large or small are each accompanied by their own set of challenges.
If you use a container that’s too small, the plant inside will become pot-bound, and its roots will grow in circles. Therefore, it won’t get enough food and water from the soil, which can lead to starvation and dehydration.
Containers that are too large hold too much water and increase the likelihood that the plant inside with end up overwatered.
Additionally, remember that when your houseplant grows, its roots below the soil grow too. Timely repotting can help extend your houseplant’s life. You’ll need to transplant your houseplants to larger containers every few years.
Faster-growing plants like pothos and philodendrons will need a bigger pot sooner than slow-growing ones like snake plants and jade plants.
Use a High-Quality Potting Mix
The benefits you get from using a high-quality potting mix can hardly be overstated. This potting mix is what your houseplants will be spending their entire lives in, so I recommend spending a little extra and going for higher quality.
Also, don’t use regular garden soil as a potting mix. Otherwise, you risk bringing soil-based fungi and pathogens indoors. In addition, garden soil can be too clayey or may compact too easily, increasing the risk of waterlogging. It’s not as nutritious and fertile, either, so there’s much you can gain from using a good potting mix.
Fertilize Your Houseplants Regularly
Plants get nutrients from the soil. But where do these nutrients come from? How come the soil just doesn’t run out of nutrients?
Well, it does, eventually. Nutrients are usually restored to the soil when plants die and decompose, but we don’t want that. We want our houseplants to live.
While it might take a long time, the nutrients in the potting mix will eventually run out. But even long before these nutrients run out, your houseplant will have a hard time getting its fill simply due to the decreasing concentrations in the soil.
Therefore, you can ensure your houseplants stay nourished and well-fed by using fertilizer.
For most houseplants, standard all-purpose fertilizer will suffice. You should fertilize only during the growing season, which is spring to summer for most plants. Don’t fertilize dormant plants during winter.
Most houseplants do wonderfully when they’re fertilized every two months during their growing period. You can fertilize as frequently as once every 4-6 weeks, depending on the species. Fruiting or flowering houseplants will need different types or dosages of fertilizers at different growth stages.
For instance, tomato seedlings may need a balanced NPK fertilizer at planting but will need a low-nitrogen, high-phosphorus fertilizer during the flowering and fruiting stages.
Additionally, it’s always safe to use fertilizer at half the recommended strength. Overfertilization is yet another dangerous plant killer.
And, if you’d rather not use commercial fertilizer, you can use homemade compost. This works best in garden-based soil, but with some handiwork, you can topdress or mix in compost to your potting mix without disrupting already-potted plants.
Ensure Your Houseplants Get Plenty of Sunlight
Sunlight is what allows plants to make food out of nutrients via photosynthesis. Your plant could have the most fertile soil in the world yet still starve to death if placed in a dark room.
Plants have varying sunlight requirements. But most common houseplants need partial shade. This equates to about 3 to 6 hours of sunlight a day.
Some houseplants, especially flowers, need more sun. Sunflowers and daisies, for example, need to see the full sun. They need more than 8 hours of direct sunlight every day.
Only a handful of houseplants can make do without seeing the sun for at least a few hours daily, and these fall into the full shade category. However, even these plants can’t survive a dark room and would be better off health-wise with several hours of exposure to low-intensity sunlight.
When it comes to sunlight, I recommend being very generous with the amount of exposure you allow.
More exposure usually doesn’t hurt. Some shade-loving plants can indeed incur burns, but that usually only happens if they’re exposed to extreme summer afternoon sunlight. Rotating your plant by 90-180° every time you water is often enough to reduce the risk of burning the foliage or the plant becoming leggy.
Still, it’s essential to understand how much sunlight your houseplants need and position them accordingly.
- Full-sun plants should be kept near southern windows.
- Partial-shade plants are best kept about 5 feet (1.5 m) away from eastern or western windows.
- Full-shade plants can be kept near a northern window or up to 8 feet (2.4 m) away from a bright but lightly curtained window.
Sunlight not only activates your houseplants’ tiny food production factories but also keeps a host of diseases, pathogens, pests, and unwanted insects at bay.
Inspect Your Houseplants Regularly
A regular inspection of your indoor collection will inform you of any lurking dangers. Many of the things that trouble plants are inconspicuous, so you need to examine your houseplants closely to get a better idea of what’s going on.
I recommend closely looking at your houseplants at least once every few weeks. Check for pests and diseases and possible signs of stress, or just analyze the plant’s overall condition.
While you’re at it, you can also clean the foliage by wiping it with a clean, damp cloth. This will reduce the likelihood of a future pest infestation.
Deal With Pest Infestations Promptly
A pest infestation can be frustrating to run into. Especially if the little critters can fly, and it’s especially not fun if you’re squeamish.
When dealing with an infestation, time is of the essence. The most common indoor pests can reproduce in as little as a week. Therefore, you should always isolate affected houseplants and fight the pests using insecticide.
But, if you’d rather not use commercially available insecticide, you can make your own plant-friendly insecticide using dish soap and a few other things you could probably find around the house.
If there are a few insects with no visible webbing or chew marks on the leaves, you can pick the crawling insects with tweezers and drop them in a tub of soapy water. You can also place sticky traps near the plant to catch flying insects.
Houseplants typically live for two to five years. Theoretically, a houseplant could live forever under perfect conditions and with no threat of attack by pests and pathogens.
This is possible because plants don’t weaken with age as humans do. In humans, senescence causes our cells to stop dividing, leading to slower healing and reduced organ function.
Plants aren’t affected by senescence, as their stem cells (found in the meristem) can divide indefinitely. A plant is equally as resilient against external damage now as it will be later, given its health doesn’t wane due to poor conditions.