Having a cactus plant in your home provides an eye catching and interesting addition to your décor, especially if that cactus is quite large. However, larger cacti are hard to come by.
Cactus plants naturally grow much slower than most plants, thanks to adaptations for living in their natural desert habitat. A large cactus houseplant is not only impressive because of its looks, but also because of the commitment and time required for it to reach that size.
So if you own a cactus but it doesn’t seem to be growing like your other houseplants, you’re probably wondering – how fast do cactus plants grow?
Most types of cactus plants grow very slowly. If being grown from seed, they might only reach a few centimeters in height after the first 2 or 3 years, depending on the species. From there, most cactus plants will grow about 1-3cm per year, with a few notable exceptions which can sometimes grow up to 15cm per year.
Cactus plants are some of the most low maintenance plants that you can choose to grow in your home, but this comes with the trade off of requiring plenty of patients.
In this article, you’ll learn exactly what to expect in terms of the speed at which your cactus will grow and how you can help it go a little bit faster.
What Makes Cacti Grow So Slowly?
There is a reason that growing cacti as a houseplant has become so popular lately, and its not just because they are totally adorable.
Cactus plants are a member of the succulent family, which are notorious for being hard to kill. Perfect for beginner plant owners, cactus plants are extremely well adapted to surviving in times of neglect.
Native to deserts around the world, cacti are naturally equipped to handle insufficient nutrients, extreme heat, and unpredictable rainfall. These intensified survival tactics cause cactus plants to focus most of their energy towards simply staying alive, rather than rapid growth.
Without these unique adaptations, cacti would never survive the harsh desert climate and die before they have even had the chance to reproduce.
A Plant Without Any Leaves
One of the cactus plants most important adaptations for surviving the desert climate, is the absence of leaves. Leaves are typically used in the process of transpiration, which is when water absorbed by the roots of a plant is later evaporated through the leaves.
Leaves are also very important in efficient photosynthesis, where the plant uses rays of light from the sun to create energy for rapid growth.
Having larger leaves means a plant will have more chlorophyll and a better ability to conduct photosynthesis. These plants who are able to conduct photosynthesis at a very rapid rate, are able to grow much faster.
Without leaves, cacti have much less chlorophyll. This limits their ability to create plant food from the sun, which means they will grow much slower than other plants.
Instead of leaves, cacti have areoles and spines. These don’t play a role in energy production, however, the spines in combination with strategically angled ridges are able to produce some protective shade for the body of the cactus.
Stomata are tiny pores located on the surface of plants, which allow them to take in carbon dioxide to be used for photosynthesis. In order for any plant to grow quickly, it requires access to a lot of carbon dioxide.
The catch is that whenever the stomata are opened, some water is able to evaporate out while the carbon dioxide is rushing in. Since cacti need to store as much water inside them as possible to survive long periods of draught, having their stomata open too long is a clear disadvantage.
This is why cacti have evolved to have fewer stomata than other plants. These stomata also tend to only open at night when temperatures are cooler, to further protect against evaporation.
Since the there are fewer stomata which are open for less amounts of time, cacti are unable to take in very much carbon dioxide, limiting their ability to perform photosynthesis.
However, living in the desert means that survival via water retention is much more important than creating energy for faster growth.
How Can I Help My Cactus Grow Faster?
There are a few things you can do to help your cactus plant grow faster and it starts with creating the correct environment.
When starting from seed, remember it is important to keep the cactus seedlings covered during germination. This will help to create a warm and humid environment for the delicate cactus seedlings to start out.
But, keeping them covered too long will will prevent necessary ventilation from occurring and possibly stunt the seedlings growth.
Once the seedlings are ready to be potted, or if you have bought a cactus from the store, follow these simple steps to help them thrive as efficiently as possible:
1. Becoming Familiar With The Different Types Of Cacti
Selecting the right cactus plant for your home can be a bit overwhelming, since there are so many to choose from. There are about 2000 different species of cacti out there after all.
When deciding on the right type of cactus, it’s important to ask yourself what you are expecting from it.
Are you just looking for a cute piece of décor, do you want a plant to cherish and watch grow for the next 20 years, or, are you looking for a cactus who will produce beautiful floral displays?
The Golden Barrel cactus from the genus Echinocactus, is a good beginner choice for growing indoors. These need plenty of light, but not much water.
The Golden Barrel cactus can thrive with watering as infrequently as once every two or three months. Even with so little water, you can expect them to grow about 1-2cm per year. In nature, These cacti will produce small yellow flowers in the summer, but only after reaching about 20 years in age.
Averaging about 2-3cm in height per year, there are many different types of cacti in the Ferocactus family which make common houseplants. These will look similar to the Golden Barrel cactus, sharing the signature barrel shape.
Like most cacti, they prefer bright light and little water. These cacti can also produce flowers of varying colors like pink, yellow, purple, or red depending on the species, once they have reached maturity.
The Saguaro cactus is probably what you have in mind when you try to picture the iconic desert landscape. Able to reach over 75 feet in height, with a lifespan of over 200 years their slow growth rate makes them a good choice for growing indoors.
These cacti will usually grow between 2-15cm per year, depending on the growth stage. But, it can take up to 40 years for a Saguaro cactus to flower.
If colorful blossoms are what you’re after, the Christmas cactus (often interchangeably called the Thanksgiving cactus) will be the right choice for you.
These cacti have a very unique look, with stems closely resembling leaves which are stacked on top on one another.
In the United States these are usually sold right before the Thanksgiving holiday in November, where they will conveniently produce beautiful pink blooms for the holiday season.
2. Choosing The Proper Container
When potting a cactus plant, always choose a container which is at least 3-4 inches larger in diameter than the cactus itself. The idea is to give the cactus room to grow, because you don’t want to be repotting too often.
A larger container will give the roots a chance to spread out and secure more nutrients. This will also help to stabilize the cactus plant once it gets larger.
A terra cotta or clay pot is the best choice for cactus plants.
3. Use Well-Draining Succulent Or Cactus Soil
Choosing the appropriate soil to pot your cactus in is absolutely vital to its survival. Cacti have evolved to live in sandy, rocky, and hard soil conditions where water and nutrients are scarce.
Most garden centres will carry specific cactus or succulent soil mixes made by popular brands that everybody would recognize. However, these mixes can sometimes be overpriced and often unpredictable, with some still holding more water than desired.
Making your own cactus soil is a cheaper and more predictable option. A basic cactus soil mix will be 3 parts potting soil, 2 parts coarse sand, and 1 part perlite.
Each of these ingredients can usually be purchased individually at most garden centers. From these ingredients you can adjust the mix based on how your cactus is responding and the conditions in your specific home environment.
4. Avoid Overwatering
Cactus plants are traditionally thought of as the perfect plant for beginner plant owners, due to their ability to survive in times of neglect. However, this doesn’t mean your plant will be fine if you never water it.
In the desert, rain comes in seasons. So if you want to help your cactus plant grow as fast as possible, it is important to mimic the seasons with your watering.
During the growing season (from the spring to fall) cactus plants will thrive with regular, shallow, watering. Watering your cactus plant about once per week during the hottest months will help to stimulate growth. But remember not to water too deeply, and always allow the soil to dry between waterings.
During the colder months, cactus plants will basically go dormant. When this happens, it is important to lessen watering to about once per month.
Since cactus plants are designed to retain water, when a cactus plant is overwatered it will begin to store too much inside of its cells and become bloated. Unfortunately at first, this may be mistaken for a sudden growth spurt.
But when this happens, any remaining water will linger in the soil. The chances of root rot will be significantly increased and the cactus will die. It is extremely important to avoid this situation, because once you have started to overwater you cactus, not much can be done to save it.
5. Succulent Fertilizer
Using a succulent fertilizer can help give your cactus the boost it needs to grow faster. Use a water soluble liquid fertilizer which is low in nitrogen regularly while watering during the growing season.
However, avoid using fertilizers during the colder months since the cactus plant will not be using much nutrients during this time.
6. Provide Lots Of Sunlight
In the desert there are very few opportunities to find shade or shelter. In this environment, the sun is hot, powerful, and rarely absent.
Try to place your cactus plant in the sunniest window of your home, preferably south-facing. Since most cactus houseplants are small, a windowsill is usually the best bet for the most direct sunlight.
Remember to turn your cactus plant each week, because the more sunlight it gets, the more efficient it will be at conducting photosynthesis.
7. Maintain Consistent Temperatures
The temperature in the desert is fairly predictable. Keeping temperatures as consistent as possible is important for your cactus to remain healthy. The optimal temperature for your cactus will be between 65-80 degrees Fahrenheit.
Avoid placing a your cactus on a windowsill if there will be a cold breeze in the winter, or if its right above a blasting heating vent. These extremes would cause excess stress for most houseplants.
In general, cactus plants immediately provide an adorable and exotic aesthetic to any space. But, you should not expect to see any dramatic shooting growth from your cactus plants.
Growing cacti to be quite large is possible, but it is a very long term investment. This is because cacti are driven by millions of years of very selective adaptations for surviving in some of the harshest habitats on earth.
With seedlings reaching maturity at a just a few centimetres tall in 2-3 years and most adult cacti growing only a few centimetres per year after that, having a large cactus is an impressive achievement.
But, if you are willing to provide an optimal habitat for your cactus based on its own specific and unique definition, it will be extremely rewarding in the long run. Although there is no way suddenly help your cactus double in size, there are a series of small things you can do to help it grow just a little bit faster.
Amber Noyes was born and raised in a suburban California town, San Mateo. She holds a master’s degree in horticulture from the University of California as well as a BS in Biology from the University of San Francisco. With experience working on an organic farm, water conservation research, farmers’ markets, and plant nursery, she understands what makes plants thrive and how we can better understand the connection between microclimate and plant health. When she’s not on the land, Amber loves informing people of new ideas/things related to gardening, especially organic gardening, houseplants, and growing plants in a small space.