How Long Can Cactus Last Without Water?

Among cactus growers, there are as many theories about how long your cactus can survive without water as there are people who grow them.

Some growers will say that, if given enough time, a cactus can survive for weeks; others will say months or even years.

While there’s no official set rule for when and for how long a cactus can survive in dry conditions, there are some general guidelines that apply to all cacti.

The first thing that comes to your mind when you think of a cactus is a desert plant that can go ages without needing any water.

That has led many people to believe that a cactus doesn’t require much water to survive. However, contrary to widespread belief even though the cactus has adapted to life in the desert and prefers dry soil, the plant still requires a sufficient amount of water, particularly during the growing season.

So, to answer the question of how long a cactus can last without water, we will be providing you with all the details regarding watering a cactus plant. In general, a desert cactus can go up to two years without requiring water, which is mainly because it has grown to develop thicker stems that can store plenty of water and have a protective layer, which prevents the loss of water.

However, the same thing isn’t applicable to indoor cactus plants since they grow in vastly different conditions. The indoor specimens of cactus plants do need frequent watering, which depends on the cactus species.

In this article, we will be discussing how long a cactus plant can last without water in greater detail, and help you understand how the cactus has adapted to survive in arid areas.

If you want answers to your questions, you should read on to learn everything that there is to know about cactus plants.

Detailed Explanation of How Long a Cactus Lasts Without Water

Despite the cactus being a desert plant that has grown to survive in arid conditions, these plants can’t last long without water forever.

According to science, the cactus is a living thing and every living thing on this planet requires water to survive.

The cactus is a desert plant that generally stores water in its roots and stem and is much more efficient in doing that than non-desert plants.

Apart from that, the cactus doesn’t let any water go through evaporation, since it doesn’t have many leaves.

That may result in you believing that the cactus plant has designed a deep root system, so that it may acquire water from the underground more efficiently.

However, that’s not the case as cacti have an extensive and shallow root system that remains only a couple of inches beneath the ground.

The roots of the cactus also extend a couple of meters from the plant and help in collecting water.

These plants will develop their roots quickly during the rainy season and these roots will shrivel up and break apart once the dry season arrives, which helps the plant in storing water.

For example, the cactus species named mammillaria and other small species of cactus can survive the entire winter season, while facing no problems without any water.

That comes down to nearly four months without any water, although the cactus must be stored at close to freezing temperatures, to some degrees up when the summer season arrives.

In comparison, the larger species of cactus-like the Barrel and Fero cactus can survive for longer periods without water, as they have a larger storage capacity for storing water in their stems.

How Does a Cactus Plant Live Without Any Water?

We have already mentioned that all living things on the planet need water to survive. However, the water supply is scarce in the natural areas where cactus plants generally grow.

The cactus has, therefore, developed a set of unique features to adapt to its environment, which allows them to conserve the little amounts of water they receive during the rare rainfalls.

For example, the cactus plant has prickly spines, which are in general highly modified leaves. There are two main functions that these spines serve, which are:

  1. Protecting the cactus plant from animals in the desert that may want to feed on them.
  2. Reducing any water loss by restricting dry airflow near the cactus plant.

Most cactus plants also have a shallow but extensive root system, which helps them in soaking up any water left by the little rainfalls they experience in the desert.

As rainfall is sporadic in the desert areas, the cactus plants have developed thicker stems, which help them store massive quantities of water for prolonged periods.

For example, a Saguaro cactus when fully grown can absorb and store around two hundred gallons of water after a heavy downpour of rain.

How Much Water Does a Cactus Plant Need to Survive?

This is a question that is a little difficult to answer, mainly because there isn’t any specific measure relating to the amount of water that a cactus plant needs to survive.

In fact, whether you water too little or too much, it’s difficult to get the right consistency, and one of the main reasons why so many gardeners lose their cactus plants.

You can’t generalize how much water a cactus plant needs and how often you should be watering your cactus plants because every cactus is different.

Guidelines to Follow While Watering Your Cactus:

  1. The period from spring to fall is the growing season, and during this period your cactus plant needs regular fertilizing and watering. When the hotter summer months arrive, you should water your cactus at least twice every week.
  2. On the other hand, most cactus plants are living in a state that is semi-dormant from late in the fall to early in spring, and during this period they may not require a lot of water. If you’re living in a locality that gets plenty of rainfall, you don’t need to water your cactus plant in this period.
  3. You should always allow the soil to be completely dry before you water your plant again. Therefore, you must check and ensure that the top layer of the soil has been dried completely before you give more water to your plant. You can use a water gauge to figure out the moisture level of the soil and can even stick a finger into the soil for gauging the moisture level. You shouldn’t water the plant if the soil is sticking to your fingers.
  4. Most plant experts claim that the cactus only needs a small amount of water in the winter season, while others claim that the plant doesn’t need any watering during winter. You must carefully watch and test your plant to identify how much water it requires during the colder months.
  5. If you have a cactus plant in a pot it will need more water than a cactus plant that has been planted in the ground. So, you will need to adjust the amount of water you give to your plant in the same manner.
  6. You should always look for signs of overwatering and under-watering your cactus plant. A cactus that has been under-watered will appear deflated, skinny, pale, or rubbery.

An over-watered cactus can appear to be plump and healthy at first, but if you are waterlogging the cactus, it will cause the roots to start rotting and die. That will cause the plant to start getting soft and turning pale.

How to Identify How Much Water Your Cactus Needs?

It can be tricky to identify how much water your cactus needs, especially if you don’t know its species.

Thankfully, there are some ways you can still water your cactus and we will help you out in this regard. Answer the following questions truthfully to identify how much water your cactus needs.

Does It Have Any Spines?

In general, if there are a lot of spines on your cactus plant, it will require less water than a plant with fewer spines.

A lot of cactus plants come with spines that have been modified into leaves, which help in preventing water loss via evaporation.

The spines of the cactus plant are responsible for trapping the air on the plant’s surface, creating an insulating layer meant to reduce evaporation and transpiration.

These spines also help in lowering the temperature of the plant.

Does It Have Stems or Leaves?

Many cactus plants don’t have any leaves. In general, the cactus plant will need more water if it has thin leaves on top because cactus with thin leaves have a higher surface area.

That means they are losing water much faster than cactus plants with fat and thick stems.

Is It Large or Small?

Generally, small cactus plants need less water than larger cactus plants.

Does It Have Solid Stems?

Check to see if your cactus plant has a solid stem because if it does, that means it is excellent at conserving water.

The stem will serve as the main area for storing water for the plant. So, if the stem of the cactus is ribbed, the cactus plant will be able to swell or shrink with water in the same manner as an accordion.

How to Water Your Cactus Plant?

You can water your cactus plant in several methods, and the one that you choose will depend on your preference. In general, if you have planted the cactus plant in a pot, you should follow these steps:

  • Place the potted plant in a saucer with enough water
  • Allow the plant’s roots to absorb all that moisture for a period
  • When you think that the soil in your potted plant has gotten wet halfway upwards, you should take it out of the saucer.

Most people like to submerge their cactus plants in water as a way of watering plants. However, in many instances, this method for watering only applies to cacti that have thick and big roots.

An alternate method for watering your cactus is by applying water to the soil’s surface. The amount of water you use for this method depends on where you have stored your plant and how much heat and sunlight it receives.

So, if your cactus is placed in an open area and has direct access to sunlight, you will be required to water it more.

Irrespective of the method you choose for watering your cactus, always ensure that you’re not overwatering the cactus.

It’s more dangerous to overwater your cactus than underwater it. You should also remember the cactus species of your plant, as that will guide you in watering it.

Final Words

In conclusion, while cactuses are hardy plants that go for years without water, many can survive only a few days without water.

While a desert cactus can survive several days without water, the more arid conditions would make it very unlikely for a cactus to survive for more than a week. After a cactus dries out for an extended period, its roots can die, and the plant may die.