How Long Can a Saguaro Cactus Go Without Water? ( You Will Be Awe)

How Long Can a Saguaro Cactus Go Without Water?

It’s true that cactus can’t survive completely without water. All living things require water. However, a cactus is designed to be able to live without much water. Additionally, it utilizes the water it has much more efficiently than other plants.

Since it has no leaves, it can’t let its water evaporate as quickly as other plants. The stems of this plant are sturdy and have lots of space to store water and with a protective layer that holds the water within.

A publication I got at the Arizona Sonora Desert Museum near Tucson stated that they had made a trial with an adult Saguaro.

It was alive after five years.  However, it was severely dehydrated and  in poor overall health. Saguaros are able to store a lot of water within their bodies, which is slowly lost , despite temperatures that in the Sonoran Desert occasionally surpass the 115 degree F level.

However, this doesn’t apply to cacti that grow indoors since the conditions are different. Indoor saguaro require regular watering , depending on the kind. 

In this post,I will discuss  in detail how long a  saguaro cactus plant can survive without water and what the natural strategies it uses for less evaporation, and for more  water preservation. . 

How  Can a Saguaro Cactus Live Without Water? ( It’s Detailed Strategies )

Saguaro typically utilize the water that is stored in their stems and roots far more efficiently than non-desert plants.

  • Additionally, they don’t let water evaporate in the same way as other plants since they don’t have leaves.
  • They tend to grow larger roots quickly after the rains arrive. But the roots shrink and fall off once the dry season gets underway to aid in storing their water intake.
  • Spines from the Saguaro Cactus plant are actually highly modified leaves.They serve two primary roles: they guard the cactus plant against desert animals who want to eat them, and also they limit water loss by limiting the circulation of dry air around the plant.
  • A fully mature Saguaro can store and absorb around 200 gallons of water during a downpour.
  • To know how cacti manage to keep water in and retain water, it is important to keep in mind that in humid conditions, plants are constantly sweating.
  • Water is absorbed through the roots, and then rises to the leaves as a part of the sap (a fluid transported in xylem cells) and evaporates via the stomata.
  •  The stomata have to open to suck in CO 2 and exhale O 2.
  • In normal conditions, plants lose 75 percent of the water absorption by its roots. This is not significant in tropical rainforests however is not possible to the Saguaro.
  •  Spines of saguaro can be a distinct variation of leaves.The spines add a bit of shading to the cactus, as they project their shadow on the stem. They also gather dew. When the dew drips onto the earth, their roots reroute it to the Cactus.
  • To prevent water vapor being able to escape, cacti cover their stomata throughout the day and open them only in the evening, when temperatures are low and there won’t be so much transpiration.

Instead of stomata that open during the day, cacti have stomata that open at night. This helps them survive in extreme conditions. Cacti can still get the carbon dioxide they need to make their food without having their water supply zapped. They store up the carbon dioxide overnight and use it the next day to make their food.

Ask Dr. Universe website
  • To save CO2 until the time of daylight, saguaro cacti have developed a metabolism that lets them conserve it within vacuoles during the night. And  they transfer it to chloroplasts once the sun rises. Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant. This way they make more efficient use of water.
  • The waterproofing wax, the steep stems and an additional skin of thorns covers the stem with a cuticle which makes it more waterproof . It also is light in color and reflective of sunlight. This helps reduce its temperature and consequently also, the process of evaporation..
  • The Ecologist Harold A. Mooney and his colleagues investigated the phenomena within Copiapoa gigantea. Incorporating temperature sensors into the stems, they discovered that the temperature of the tissues that were covered with wax ranged from 0.5 up to 2 degrees less than regions where the wax cover had gone away.
  • Another factor was observed by Mooney that the majority stems were tilted to the north, so solar radiation was only reflected perpendicularly to the top of the stem.  However, it did not reach the sides. Therefore, the cacti slowed down the radiation they received and helped them to not become so hot.
  • Actually, these spines are highly intelligent organisms that have evolved specifically to survive. The majority of strains are able to capture the humidity of the air, even in very small amounts.
  • The other spines are angled in a manner that they trigger droplets to fall to the roots in the plant thereby creating self-hydration . This is why a tiny spray every week on your cactus’s roots is enough to help it remain alive.

How Do Saguaro Cacti Conserve Water to Live Long?

Studying the microscopic structure of the spines and trichomes , researchers at the Beijing National Laboratory for Molecular Studies found that drops of water would always fall down the stem, no matter if the spine was set in a downward position and the drops were required to defy gravity. This is due to the conical shape of spines as well as their longitudinal grooves.

Recently, a team at the Pohang University of Science and Technology (South Korea) has demonstrated that the spines from this cactus can condense water vapor into tiny droplets that can then be deposited on trichomes (meaning “hair”, are fine outgrowths or appendages on plants).

The trichomes have a hydrophobic nature(Hydrophobic is a characteristic of an element in which water repels it). Therefore, the drop sits on them without soaking them, and then it evaporates slowly by small amounts. When the droplet size is right , it will be absorbed in microseconds in the hydrophilic zone beneath the trichomes.

It has been calculated that a saguaro could accumulate 760 liters of water after the occurrence of a storm. Saguaro has ribs that can increase their water volume when there is water available , and decrease the amount when they are depleted of it.

How Saguaro cactus Produces Energy ? 

The majority of plants require light and sun to perform photosynthesis and convert light rays into energy .

It is exactly the opposite to saguaro cacti.  Stomata are opened during the day to collect carbon dioxide in the air; the cactus opens this at night when the humidity is higher. It is able to minimize the loss of water. Organic acids store CO2 at night and are transformed into sugar in the daytime. It is a process of metabolism of the saguaro cactus.

How Do Thorns Help the Saguaro Cactus?

The existence of spines serves the thermal regulation. They not only shield the plant’s body from the heat from the sun  but also  make sure to remain at a constant temperature through the creation of an air-insulating layer.

How Do I Know If My Saguaro Needs Water?

A best practice is to examine what is between the ribs on the Cactus. If you are unable to get two or three fingers in between the ribs or the skin is loosened in the event of pressing it,  then the cactus is in need of water.The skin of a well-hydrated plant will feel firm to the touch. The Saguaro needs about 10-inches of water per year.

How Do You Know When a Saguaro Cactus Is Dying?

Changes in color are one of the most obvious indicators that your saguaro may be unhealthy. If your cactus’s colors change from a gentle blue/green/gray hue to yellow, and especially in the event that it’s floppy or shrunken, it could suffer from root decay.

How Much Water Does a Saguaro Need to  Last Several Months?

1500 gallons — one mature saguaro has the capacity to hold 1,500 gallons of water (that’s six tons) within its soft pulp, enough to last for several months. It could lose up to about 2/3 of its stored water and live.

How Deep Are Saguaro Roots to Collect Water?

When the saguaro grows to four feet tall, its roots start growing continuously for as long as 55 years. They extend four feet away from the stem in all directions and up to three inches in depth. The hairs of the roots have special characteristics that allow for the capture of up to 200 gallons of water during rain.

As stated in  Ask Dr. Universe website  Cacti can store a lot of water, too. When it rains a lot, the saguaro cactus takes in so much water it weighs up to about 4,800 pounds, or just a little less than a minivan.  


Saguaro is a rare cacti, which can live many years without any water. Because they can store water into their system. A healthy saguaro can store 6 tons of water in its pulp. 

So in a drastic environment, arid desert,  they can survive without water. How heated the environment is doesn’t matter, saguaro  doesn’t evaporate their  stored water. 

Anwar Hossain

My name is Anwar Hossain. I am a cactus lover, researcher, and cactus blogger.

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