Some cactus varieties can grow incredibly high, but it will take a very long time to get there. For example, the Saguaro can grow as high as 45 feet. However, it will take as long as 200 years for that cactus to reach that height.
How fast do cacti grow?
Generally speaking, cacti grow slow. In some types, you can hardly notice visible signs of growth. Others grow at a relatively faster pace. On average, you should expect your cactus to grow anywhere between less than half an inch to about an inch per year. And there are some cacti that can grow as much about six inches annually.
To better understand the pace of growth of most cacti, it is worthwhile to look from the vantage point of their growth stages.
Like many plants, cacti grow from seeds. However, you can also grow cacti from cuttings. If you are starting with a seed, you will first have to wait for it to germinate. The germination of cactus seeds will vary from one type to another. Some cactus seeds will germinate in a matter of weeks while others take several months.
In general, cactus seeds germinate faster in an indoor environment compared to an outdoor environment. This is because an indoor environment can be easily controlled. If a cactus seed is germinated outdoors, it may take several years for germination to take place. This is because the seed needs to wait for the right environmental conditions.
If you are starting from a seed, you might see spines growing from the seed in one month. However, take note that not all cactus species grow spines. Instead of waiting for spines to grow, you should wait for a seedling to appear from the soil.
If you do not notice spines or seedling growth in a month, do not despair. There are just some cacti that take more time to germinate. Just be patient.
Half a year
If you have successfully germinated your cactus seed, you may hardly see any difference within six months. It is not unusual for many cacti to remain the same size as a marble ball within six months.
In a year, your cactus will essentially look the same as it was a few months ago. Although there might be no visible signs of growth, your plant’s needs have changed. Specifically, it needs to be moved from the propagation tray to its own pot.
Two years and beyond
Most cacti take years, decades even, to reach full maturity. As such, do not expect significant growth from your cactus.
Are you doing something wrong?
Although cacti have the reputation of growing slowly, it is also entirely possible that you are doing something wrong that is causing your plant to grow at a sluggish pace.
1. Using the wrong pot size
From germination to a year later, you will need to repot your cactus. Here, it is crucial to use the right size of pot for your plant. Placed in a container that is too small, your succulent is deprived of the nutrients it needs to grow further. Simply put, if you use the wrong pot size, you are limiting your plant’s growth potential. You may need to repot your cactus several times in its early stages.
After moving your cactus to a new pot, you should give it ample time to recover. Otherwise, you are subjecting it to stress. Cacti are extremely adaptable. However, they need to be given enough time to adjust to a new environment. After repotting, keep your plant away from direct sunlight for a couple of days. This will give it the time it needs to recover fully. After a few days, you expose it to more sunlight on an incremental basis.
Cactus can withstand long periods of drought but like other succulents, it cannot tolerate excessive moisture. In fact, overwatering can be downright fatal for these plants. One possible reason why your cactus is not growing is that you are overwatering it.
The signs of overwatering in young cacti are not always readily apparent. In fact, you might be overwatering your plant without even knowing it. Cacti can continue to grow and show no signs of overwatering for weeks or even months. But when these signs do begin to emerge, it may be too late to save your plant.
Excessive moisture is the number one cause of death in cacti and succulents. When you give an excessive amount of water to your cactus, the roots sit in the water for a long time and this leads to root rot. When the plant’s roots begin to rot, they lose the ability to supply the whole plant with water.
That is when you will see visible signs of overwatering. These signs include discoloration, soft leaves and mushy texture. If the root rot is not extensive, you might just be able to save your plant. If there are just a few rotten roots, you can cut these away and plant your cactus in another pot.
4. Lack of ventilation
Between germination and the early stages of growth, the container of the cactus seedlings needs to be wrapped with a plastic cover or a transparent lid. The purpose of the plastic cover is two-fold. First, it helps the cactus to get access to enough sunlight. Second, it helps the soil retain moisture.
Once the seedling is established, you will need to remove the wrap gradually. Removing the plastic wrap facilitates ventilation which is an essential ingredient for growth in young cacti.
Are there ways to make a cactus grow faster?
The best way to make your succulent grow faster is to avoid the things that impede its growth. However, there are a few tricks that you can use to speed things up a little.
1. Repot your cactus
Choose a ceramic container that is a bit larger than your cactus’ current pot. Make sure that you fill the pot with a soil mix specially formulated for cacti. Alternatively, you can create a potting mix made up of one part organic soil and another part made of coarse sand. Also, be sure that you plant your cactus at about the same level as it was in its original container.
2. Move your cactus to a brighter spot
Find the sunniest area in your home. In most houses, this will be in a south-facing area. Make it a point to keep that area warm for your plant. Cacti prefer areas with a temperature range of 65 to 85 degrees Fahrenheit.
3. Water your cactus correctly
Cacti need more water during the summer months and less during winter. The best way to water cacti is to give them just enough water to moisten their potting mixes. After watering your plant, be sure to allow excess moisture to drain out of the pot’s drainage hole.
Water your plant again only when the soil is dry. Watering frequency will vary depending on the age of the plant, the season, and the size of the pot.
4. Use the right fertilizer
Providing your plant a low-nitrogen fertilizer formulated for cacti can give it the boost it needs for growth. However, avoid giving your cactus fertilizer during winter when it will probably go dormant. As a rule of thumb, fertilize your cactus once or twice during its growth phase. Fertilizing it weekly can lead to more harm than good. Overfertilization can lead to uneven growth or even deformities.
Why are cacti such slow growers?
If you have kept other plants before, you will see a marked difference in the growth rates of those plants and your cactus. There are a few reasons behind this difference.
If you look at the places of origin of many cacti, you will instantly notice that these locations can barely support life. For the most part, that makes cacti such amazing plants, being able not only to survive but thrive in conditions that are downright hostile to plant life.
In the desert, the soil can be dry for most of the year with rain falling intermittently. Aside from that, desert soil is practically infertile, providing little to no nutrients to support growth. To thrive in this type of situation, cacti have evolved and adapted by putting their focus on survival and taking advantage of what little resources are available to them.
Instead of allocating resources toward growth, cacti use those resources to keep themselves alive until the rains come in.
Absence of leaves
Leaves serve a few critical functions in plants, including transpiration. Transpiration is the process by which plants lose water through evaporation. Transpiration is important for two reasons. It helps cool the plant and enables nutrients and water to be distributed throughout the plant. According to studies, a plant can lose as much 99 percent of water through transpiration.
If you look at a few cacti, you will see that most do not have conventional leaves. In place of leaves, these plants have spines which perform multiple functions. These include protection against animals, airflow reduction, and sun protection or shade.
The lack of leaves means that cacti do not lose as much water as other plants do. However, the absence of conventional leaves means cacti cannot produce as much food as other leaves.
The absence of leaves also translates to lower levels of chlorophyll. Chlorophyll gives plants their green color. It is also a critical part of photosynthesis, a process by which plants use the sun’s energy to create their food.
Without leaves, cacti have to rely on their stems for photosynthesis. This means that these plants can produce a considerably lower amount of food which they use mainly for survival instead of growth.
Apart from lacking leaves, cacti also have fewer stomata compared to most plants. Stomata are plant structures that open up to absorb carbon dioxide from the air. Carbon dioxide is integral to photosynthesis. When the stomata open to absorb carbon dioxide, water is also released.
Cacti evolved to have fewer stomata to limit water loss. However, this adaptation means that these plants cannot absorb as much carbon dioxide needed for fast growth.
The patience game
Even if you implement the hacks mentioned above, do not expect your cactus to grow as fast as other plants. Cacti are slow growers and there is not much you can do about it. But that is part and parcel of the beauty of keeping cacti.
Image: istockphoto.com / fotocelia