Cactuses are notoriously slow to grow. It’s one of the reasons you can see them displayed in tiny containers for so long.
But why are they so slow to grow? Is there something you can do about it? And are there cactuses that can grow faster?
If you’re new to cactuses, these are probably some of the questions you’re asking yourself. And it’s understandable that you may be a bit worried that you’re doing something wrong.
But there’s no need to worry. It’s not that cactuses don’t grow, it’s that their growth rate is slow and tedious, and it can take a few years until they can reach their mature size.
In this article, I’m going to cover all these topics and also give you tips on what may hinder your cactus’ growth even further and what can you do to speed up its growth.
How Fast Do Cacti Grow?
Not all cactuses have the same growth rate, but on the whole, they’re not fast growers by any stretch of the imagination.
The growth rate of some cactuses is painfully slow, other cactuses may be doing somewhat better. On average, cactuses grow a few centimeters per year, or in some cases, a few centimeters every 2-3 years. Some cacti do much better.
For example, the Carnegiea gigantea can grow as much as 15 cm per year, but this is a relatively rare exception, and most cacti species will have a slow growth rate, in the single digit numbers.
So why is your cactus growing so slow? And is there anything you can do about it?
It’s important to remember that cactuses can survive in climates with extreme heat and little to no rainfall. Therefore, a plant adapted to survive harsh weather conditions will not be bothered with growing fast.
The growing capabilities of cacti are also hindered by the absence of branches and leaves, which are packed with chlorophyll, the chemical responsible for converting sunlight into energy.
In the absence of leaves and branches that would contribute to the energy production of cacti, these plants will have a slow and tedious development adapted to the harsh desert climate they’re native to.
But the environments in our home aren’t as harsh and unpredictable, and even better, the conditions in your home can be manipulated to best suit the needs of your cacti.
That said, some conditions in our home may be even hindering the growth of your cactus. Identifying these and making the necessary adjustments will go a long way in helping along the growth of your cactus.
How to Stimulate Cactus Growth?
There are a few things you can do to speed up the growth of your cactus, despite its natural tendency to take things slow.
By how much you can speed things up depends on the cactus species and the conditions you’re offering. Don’t expect the tips below to immediately bring about a significant growth spurt, but they will make a difference in stimulating growth and keeping your cactus healthy:
One of the reasons why your cacti may be growing slower than expected is the lack of enough light in your home. These plants need about 4 hours of direct sunlight daily, so find a bright spot for them close to an east- or south-facing window.
Cactuses also need evenly distributed light, so make sure to periodically rotate them to ensure that the entire plant is getting light.
If one side is receiving too much light, its green color will fade into a yellowish-white. So make sure light is evenly distributed.
Potting and Soil
Usually, cacti will do well in a small pot, especially while they’re still small and still developing. But keeping them in a small pot for too long will hinder their growth. As the cactus develops and grows, it will need more nutrients and repotting will be in order.
Of course, you don’t want to go overboard with the pot and pick a size that’s too big. If the pot is too big, you may end up overwatering the cactus and the soil may end up holding too much water, which will eventually lead to rotting issues.
Go only one size up, and replant only when the cactus outgrows its current pot to avoid overstressing the plant with frequent transplants to new containers.
I recommend clay and terracotta pots over plastic, because plastic doesn’t allow the soil to dry out as fast as clay or terracotta pots do.
The soil that you’re using for your cactus is extremely important. Don’t use soil that retains too much water. You’ll need a well-draining soil that dries out quickly after watering.
You can use commercially available soil for cacti, or you can prepare your own mix, depending on the natural habitat of your cactus.
If it’s a species that grows in the desert, you’ll need soil that combines fine sand, grit and soil. A cactus that grows in tropical regions will require a different type of soil.
Therefore, strive to closely match the soil parameters of where the cactus grows in its natural habitat.
One of the major concerns with cacti is overwatering. As plants with a high drought tolerance, cacti are extremely sensitive to overwatering. Underwatering is less of a concern as most cacti can go without water for about a month or so.
As a general rule, when watering cacti, you should check that the top inch of soil is dry. A finger dip test is all it takes to make sure your cacti isn’t getting too much water.
This means that you may end up watering your cactus every week or every other week, depending on how fast the soil will dry.
When watering, let the soil soak up the water thoroughly and remove any excess water that makes its way to the saucer at the bottom of the plant.
It goes without saying that your pot should have draining holes on the bottom to allow the soil to dry out faster.
Overwatering will not kill your cactus right away, but frequent watering will slowly cause the roots to rot and the entire plant will become soft to the touch.
Once this happens, it’s impossible to turn things around and your cactus will perish because of too much water.
Therefore, excess watering will not only hinder the growth of your cactus, but it will outright kill it. Even if your plant looks like it’s doing fine for now and it shows no signs of distress, the high moisture environment you’re creating will eventually cause irreversible damage.
For the most part, cactuses thrive in warm temperatures between 65- and 80-degrees Fahrenheit. On the lower end or the temperature threshold, they may tolerate between 45- and 55-degrees Fahrenheit during wintertime.
If you’re not maintaining right temperatures, your cactus will not grow as fast, especially if it’s exposed to lower temperatures than what’s recommended for them.
That said, there are cactuses that will have a better tolerance to cold than most cactuses. For example, the green flowered hedgehog cactus (Echinocereus viridiflorus) will tolerate 20 degrees below zero Fahrenheit.
Therefore, temperature is another factor that can either stimulate or hinder the growth of your cactus. And if you want your cactus to grow fast enough, you’ll need to keep it in its optimal temperature range.
Can Cactus Fertilizer Speed Up Growth?
Cactuses don’t require regular feeding, but occasionally they can certainly benefit from a quality fertilizer offered in small doses.
You can fertilize just once a year or 2-3 times a year, at most, during spring, summer, and fall will meet all its feeding requirements.
Cactus plants will benefit from a little feeding during times of active growth period, and it’s really not necessary to feed it more often than that. Be very careful not to overfeed, which is just as dangerous as overwatering.
As you can see, there are quite a few things that can help or hinder the growth of your cactus. At the end of the day, however, it’s more important to have a healthy cactus regardless of how fast or slow it’s growing.
Overdoing watering, sun exposure, fertilizing, and repotting can all overstress the plant and cause its premature demise.
With a growth rate of just a few centimeters per year, cactuses aren’t showy plants and they will test your patience if you’re waiting on them to reach their mature size.
On the flipside, cactuses are low maintenance and won’t make a fuss if your watering schedule has a few misses.
With their high tolerance to drought and no need for trimming or pruning related maintenance, these plants are perfect for individuals that don’t have the time for constant plant upkeep.
If you’re worried that your cactus plant isn’t nudging from its previous size, try to adjust lighting, soil, temperature and watering to see if any of these issues may be causing a stunt in growth.
Sometimes, despite your best efforts, a slow growth is unavoidable, and you’ll just need to be patient with your cactus that will eventually grow.