I have always been interested in cacti. This unique type of plant can be dangerous, yet beautiful.
I learned that cacti tend to grow slowly and that the growth rate can be affected by a variety of different factors.
How Fast Does a Cactus Grow?
It will take a young cactus approximately six months to a year to grow from a seed to the size of a golf ball. From there, it will take two or three years for the cacti to grow two centimeters. After this, the cactus will grow at a rate of between one to three centimeters per year for the rest of its life.
The Growth Rates of Common Cactus Species
The most common cactus species in the United States include the Golden Barrel Cactus. the Ferrocactus (and its subspecies), and the famous Saguaro Cactus (the most well-known species).
The Golden Barrel Cactus grows more slowly than the average species, with average growth rates of only one to two centimeters per year.
Ferrocactus species grow around two centimeters per year, about the average rate. The Saguaro Cactus can grow up to 15 centimeters per year if it is a young plant.
The Reasons that Cacti Grow Slowly
Cacti are adapted to surviving in some of the harshest environments on the planet, deserts where few species can live. A cactus will focus its energy on survival, rather than growing bigger.
It is also important to note that cacti are extremely long-lived, with the ability to live for decades in the right circumstances.
This means that a cactus will have to survive many harsh droughts and severe heat waves.
The second reason that cacti grow so slowly is their lack of leaves. Leaves help plants get the sun’s energythrough photosynthesis.
This energy allows plants with leaves to grow much more quickly than those without leaves, such as cacti. Cacti do not have leaves because sustaining leaves would require too much water.
Cactus Growth Stages
The First Month
Cactus seeds germinate (begin the growth process) very slowly. This ensures that the seedling will not grow so fast that it runs out of water.
When I planted my first cactus, I was a little worried after not seeing any growth at all within the first several weeks. The seedling finally came up after about a month.
The spines started to form soon afterward. The spines may actually appear before the seedling itself with some species of cactus.
It is not unheard of for a healthy cactus seedling to take two or three months to appear. If this happens when you are trying to grow the cactus, keep watering it every time the soil gets dry.
You should also keep the plant uncovered to ensure that it gets enough ventilation. If the seedling has not appeared after four months, it’s likely that the cactus has failed to grow.
The First Six Months
Your cactus should grow to the size of a small marble after about six months. This rate of growth seemed abnormally slow to me, but a little research confirmed that it is normal.
You should only be concerned if your seedling has failed to grow at all.
The First Year
Many species of cacti will grow to the size of a golf ball in roughly 12 months. However, don’t fret if your cactus is not this big after a year.
As long as it has grown a noticeable amount in the last six months, the plant is probably healthy. It is not unusual for a one-year-old cactus to still only be the size of a large marble.
The First 30 Years
At this point, the size of the cactus will vary greatly depending on the species. A healthy Saguaro Cactus can reach heights of over 70 feet in optimal conditions.
A Golden Barrel Cactus, on the other hand, may top out at three or four feet.
Keep in mind that a cactus will continue to grow steadily throughout its life, though the plant’s growth rate may start to slow down after it is 30 years old.
Frequently Asked Questions about How Fast a Cactus Grows
Is it possible to under-water a cactus?
It’s possible that you give a cactus too little water. However, as long as you water the cactus occasionally, it will be fine. Keep in mind that it has adapted to living in a desert environment with very little water.
When does a young cactus need to be repotted?
It is necessary to repot a young cactus when it reaches the size of a large marble. This usually takes 6-12 months. Failing to repot the cactus at this stage can kill it.
Be Patient with your Cactus
If you have experience growing plants of other types, the growth rate of a cactus may seem painfully slow. However, you’ll get used to it after tending to several cacti.
Be patient and remember that you will be able to enjoy your cactus for decades if you take good care of it.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.