Do Cactus Roots Grow Deep? Why It Matters

Do cactus roots grow deep? And what does that mean in terms of how you care for them in your home or garden? 

If you’ve been doing some research into caring for cactuses, chances are you’ve come across several pieces of information about their roots, and found that they’re actually unusually short.

Do cactus roots grow deep?

This can be surprising for many because when we think of incredibly hardy and drought-resistant plants, the last thing we think of is incredibly simple and short rooting systems.

Cactus roots are actually far more shallow than you may have first realized, but why is this the case? Scientists are still researching the matter, with some suggestions already being made.

If you want to know everything there is to know about cactus roots, then you’ve come to the right place. Below, we’ve compiled a quick guide that will tell you everything you need to know.

Just How Long Are Cactus Roots?

So, as we’ve already covered in our intro, cactus roots are known to be surprisingly short, but just how short are these?

Well, of course, this will depend on the particular variety of cacti species that we’re discussing, but in general, you can expect them to be anywhere between 5 to 10 inches (12 – 25 cm) long.

There are specific varieties of this plant, however, that can grow up to 30 inches (76 cm) deep. This is because these varieties of cactus tend to be larger and taller than other types, which requires them to have longer roots in order to support them standing up.

So, it all depends on the type of cactus.

Why Do Cactuses Have Shallow Roots?

why do cactuses have shallow roots

But why do most varieties of cactus have such short roots? How does this help their growth and development within their natural habitat? Well, it’s because shorter roots help them to maximize their water supply by covering a wider area.

Although cactuses are incredibly drought tolerant, they will require small amounts of water to thrive.

By spreading their roots width-wide instead of deep into the ground, they can cover more surface area when they do experience rain.

In addition, rain in desert areas will only penetrate approximately 5 inches of ground anyway, so this is the perfect length for cactus roots. They’ve literally been optimized to thrive there.

In addition to this, having shorter roots means that the cactus is able to absorb more nutrients from its environment to help it to survive.

By having shorter root systems, the cactus is more adequately able to gather nutrients from surrounding boulders and rocks.

Rainwater will gather more easily under these objects, and they’re more likely to be infused with the nutrients that the cactus needs.

As well as this, various desert animals, such as reptiles, lurk beneath rocks and boulders, which means there’s a chance of absorbing the nutrients from faeces from these creatures.

Finally, another reason why cactus roots are much shorter than other varieties is because it helps them to compete against other plant varieties.

Most other desert plants will have longer root systems than the cactus, so when rainfall occurs, they’ll be able to absorb the available water much faster than other plants.

What Size Pots Should I Purchase For My Cactus?

Now that we’ve covered how deep cactus roots tend to grow, and why they are short and wide, we can move on to discuss what sized pots you’ll need to help these plants.

In general, if you plan on housing a cactus, you should place them in shallow pots approximately 4 – 6 inches (10 – 15 cm) deep.

The key thing you want to make sure of is that you’re purchasing pots that are wide enough to accommodate the roots as they spread out.

Cacti also require pots with excellent drainage, so make sure it has at least one hole on the bottom for this purpose.

Final Thoughts

To sum up, cacti have root systems that are somewhere between 5 to 10 inches (12 – 25cm) deep. This short and wide root system allows them to absorb water more easily in the desert.


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