I have more than eight years of hands-on experience in the horticultural maintenance industry. I enjoy sharing many tricks of the trade.
If you are looking for an interior addition that is a bit outside of the norm, look no further than the barrel cactus. This plant can make an incredibly interesting addition to the interiorscape. It is often added to southwestern designs and contemporary layouts.
But as stated, it is an unusual addition indoors, and here's why:
- A cactus presents a real element of danger and may not be a great option in areas where it may be brushed up against or accidentally touched.
- The environmental conditions needed for these intriguing spheres to thrive are not the norm in interior spaces.
- Many people have little understanding of how a cactus needs to be cared for indoors (they have very different requirements from the typical foliar houseplant).
Of the many indoor cactus, this type has some of the most extreme needs and tolerances. Understanding what this plant needs will help you make the right decision in selection, placement, and care.
Native Habitat (Southwestern US & Mexico)
Is Barrel Cactus a Good Indoor Choice for Your Space?
If you have considered bringing one into your home or workspace, there is mostly one environmental issue to consider before making a decision:
Barrel cactus in their natural outdoor habitat live in the most extreme heat and direct sun. Due to this, indoors they require a significant amount of natural light—anything less will cause them to die. An available space with windows that receive excellent, even harsh direct sunlight from outdoors is ideal.
In order to properly water a cactus, you must have a good understanding of its natural environment.
Barrel cactus grow naturally in some of the most foreboding landscapes on the planet. These desert landscapes produce extreme scorching, relentless blazing sun and little to no precipitation for much of the year, and then monsoonal rain.
A cactus is a sort of a water storing stem that collects water through this compact stem instead of leaves. This compact design helps cacti to minimize transpiration (plant equivalent of perspiration) and maximize water storage. Barrel cactus is one of the most compact cacti, and it could be considered the water conservation tank of the desert. Everything about it is designed for water storage and protection.
Keeping this in mind, and remembering that even the most harsh interior situations are most likely no match for the Sonoran Desert, it becomes obvious that an indoor barrel cactus will not need much water very often. As a matter of fact, you can probably get away with watering only a couple times a year with good results, believe it or not.
How Often and How Much Water?
Since most barrel cacti are very tight in their grow pots, often forming a muffin-like shape as they pop out over the edges of their pot, it is nearly impossible to check soil moisture. Also, the dense intertwined spines prevent feeling its turgidness or how firm it is, so how do you know when to water?
Easy: Put it on a very lean watering schedule, watering thoroughly maybe every two months and then leaving it alone.
The best advice is that if there is any question on whether to water or not, DO NOT WATER. It is highly unlikely that a barrel cactus will die from under-watering.
The most common health issue for interior cacti is overwatering. It is difficult for us humans to just leave things alone; this constant need to do something can be compounded if one has become accustomed to caring for interior foliar plants that need more consistent care. It is a whole new approach to plant care.
How Do I Get the Water Into the Soil?
With a barrel cactus basically overflowing its pot, leaving no room for exposed soil surface, one may wonder: How can I get the water to the soil? Looking at this cactus, we see that it has a center at its top and a series of peaks and ridges that run all around the body. The valleys of these ridges will act as little irrigation troughs if you water onto the center of the top of the cactus. The water will run down the ridges and into the soil under the plant.
Other Things to Know
There are some other interesting things to know about this mysterious spherical plant.
- They are slow growing, very, very, very slow growing. There will often be no change in their shape or size in an interior environment.
- They die from the inside out. When there is a problem, you may not know until months later, since these plants start to disintegrate in their cores. It is not uncommon to hear reports of these cacti being found in a state like a gelatinous ball that breaks open and oozes all over the floor. This is commonly caused by overwatering.
- The cactus can be infested with mealy bug and/or scale. It is not incredibly common, but it does happen, especially since the plant has been removed from the environment in which it thrives, therefore weakening its natural defenses. A spray to remove the pests and a coating with insecticidal soap is the best treatment and defense for such an infestation.
- Handle with care! The spines will hurt you if touched. It is wise to place this plant out of high traffic areas and out of the reach of children.
At this point, if you have considered all the factors to keeping a barrel cactus as a houseplant and have decided that you have the right environment—and a great degree of self control—I wish you well on your new adventure with this magnificent creature.
Tips for Handling
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Questions & Answers
Question: How much water do I give to the barrel cactus?
Answer: If indoors, Barrel cactus do not need much water at all. Depending on its size you could potentially get away with watering every 2-3 months throughout the year. If in question it is best to avoid watering this plant is designed to store water and live in the harshest of environments, watering too much or too frequently will kill this plant faster than anything. Be sure it is placed in a spot that receives plenty of sunlight.
Question: I have owned an Echinocactus grusonii cactus for a year. A little while back, light green patches developed on the ridges from where the spines protrude. Is this normal?
Answer: Based on the description you have provided, it sounds like your cactus may be developing some new growth.
Question: My cactus is wrinkly at the base and some of the needles at the base are falling off. Am I watering it wrong? What should I do?
Answer: Many cactus as they age will get a crusty brown wrinkled appearing skin near the soil line, sometimes this is due to the soil base eroding down to expose part of the plant that was once below the soil. By your description I think your plant is meerly showing signs of age. If the appearance is unsightly you could add some sand or rock to bring the soil line back up.
Question: Is my Barrel Cactus okay if it has turned little green on top?
Answer: Greenery on top usually means that a Cactus is growing. As long as your Barrell Cactus is in great lighting conditions it should be fine.
Questions and Comments Welcome!!!
John on July 30, 2020:
Hi, I have a barrel cactus which is 9 inches in diameter at the base, including the spines. Silly question but how much water am I meant to use when watering, are we talking 30ml or 100ml, could you give me a bit of guidance here, please? Thanks very much, John
Anna Gibson on May 15, 2020:
I just bought a cactus and I'm not sure if it is a barrel cactus because it has long, yellow spines on top. It's also only about two or three inches tall.