Prickly Plant

How Much Water Does A Cactus Need?

When we think about a cactus, the image of a dry, hot desert comes to mind, where water is sparse yet cacti survive. Despite their ability to survive droughts, cacti do in fact need watering regularly to grow.

But how much water does a cactus need?

How Much Water Does a Cactus Need?

On average, a cactus needs to be watered every 7-14 days during the growing season but only every 1-2 months when it is dormant. It is important to ensure that the soil is soaked when watering the cactus and that the soil is completely dry before watering again.

So, you do have to regularly water this desert plant despite its resilience to drought. Several factors influence the exact amount of water a cactus requires, such as its species.

No matter its species though, it’s important to keep your cactus properly hydrated.

In general, you should add water to your cactus when the top half-inch of soil feels dry. When watering your cactus, moisten the soil, allowing it to absorb all of the water, and if it absorbs the water quickly, add more water until it comes out of the drainage holes of the pot. 

Why It’s Important To Water Your Cactus

It’s a bit of a misconception that a cactus does not need water – they do! A cactus is a plant, and all plants need at least some water to survive.

As a plant, a cactus needs water to convert sunlight into energy, or “food” for itself. This process, photosynthesis, is essential to the survival of your cactus, and any plant for that matter.

When a cactus is properly watered, it will be healthy and look its best. Depending on the species, a healthy cactus can produce beautiful blooms and will continue to grow for many years.

If you fail to water your cactus properly, it will not thrive and its growth will be stunted. Although it will be resilient to some water neglect, the plant will suffer if left unwatered for too long.

Signs of an underwatered cactus:

  • Leans to one side
  • Paler in color
  • Limpness
  • Shrivelled appearance
  • Dimpled leaves

Luckily, if you notice your cactus is looking a bit thirsty, simply give it a small amount of water and continue watering regularly to restore it. For this reason, it is better to be on the side of underwatering rather than overwatering your cactus.

how often to water a cactus

Can You Overwater a Cactus?

Any plant can be overwatered, and cactus owners do need to be extra cautious of overwatering a cactus. The issue is less about how much you water it, but rather about how often.

If you were to water your cactus every day like you may other types of plants, the cactus would likely develop root rot. Root rot is a disease that can be detrimental to your plants.

A primary cause of root rot is overwatering. When the soil is not able to dry out and is left soggy for too long, a fungus spreads over the roots and causes them to decay.

Don’t panic right away if you discover you’ve waterlogged your cactus with good intent. It is possible to rescue your cactus and repot it in new soil if there are still some healthy roots left.

How much water does a cactus need when it is time to water?

When you water your cactus, you want to thoroughly drench the soil until water begins to drip out of the bottom of the pot.

Signs of an Overwatered Cactus:

  • Browning/blackening of the leaves and/or stems
  • Browning/blackening near the base
  • Mushiness or leaking
  • Decaying

Note that you don’t want to have a set schedule or designated amount for watering a cactus because of several variables. Below, we examine what factors to consider when determining the ideal amount and frequency of water for your specific cactus.

The Ultimate Cactus Watering Kit

Check out this cactus watering bottle set. This watering set includes two plastic watering cans, two watering cone spikes and a spray bottle.

Whether you’re trying to grow your own cactus or water your already thriving plant, this water bottle set is perfect for you.

Factors That Affect How Much to Water a Cactus

Plant enthusiasts venturing into owning desert vegetation often wonder: exactly how much water does a cactus need – specifically my cactus?

To get a general idea of where to start, you must consider the plant size, the season, the humidity, and whether it is kept inside. 

Size Of The Plant

Contrary to what many may assume, a smaller cactus needs watering more frequently than a larger cactus. This is because a small cactus still has so much room to grow, so its roots absorb moisture rather quickly.

Although small cacti need water more frequently, they do not need as much. Larger cacti need a larger volume of water since they are in a larger pot with more soil to drench.

Too often, smaller cactus plants are overwatered. Always check every few days for the soil to dry between waterings to prevent root rot.

The Season

The hotter it is, the faster the soil will dry out. A healthy cactus is ready to grow in the warmer seasons and will require more frequent waterings.

Expect to water your cactus every week or so in the summer and spring. You should always check that the soil is dry, and you will need to do so every few days in the warmer months.

You can cut back on how much you water your cactus in the winter. The decrease in sunlight and cooler temperatures causes the cactus to become dormant, and a dormant cactus does not need to be watered as much.

Usually, you will only need to water your cactus once per month in the winter. Aim to keep the roots of the cactus hydrated during the colder season.


Many species of cacti prefer conditions similar to their natural desert habitat. Locations with airflow and low humidity are ideal for a cactus.

The ideal humidity level for a cactus is between 40-60%. Below that will be too dry for some cacti, but some extreme desert cacti species will be fine.

Just like with warmer temperatures, the drier the climate, the faster the soil will dry out. Be prepared to water your cactus more during the dry season.

Some cacti can adapt to higher humidity locations, however, the moisture in the air may cause mold to develop on the plant. If you live in a humid climate, place your cactus in a well-ventilated area to prevent molding.

Is Your Cactus Plant Kept Indoors Or Outdoors?

A cactus can be grown indoors or outdoors, and its location will influence the cactus’s needs and watering schedule.

When kept as a houseplant indoors, a cactus will require less water compared to those kept outdoors. On average, your indoor cacti might need to be watered every 10-14 days during the growing season and every month or two when it is dormant.

An outdoor cactus needs a bit more water due to being exposed to more direct sunlight for more hours of the day. Cacti living outside should be watered every 7-10 days during the growing season and every 3-4 weeks during the dormant winter.


So how much water does a cactus need? Well, it kind of boils down to how thirsty your cactus is.

Every cactus is unique, so it may take a little trial and error to figure out what makes your plant happy. Observe your cactus day-to-day for any signs of distress and monitor the moisture levels of the soil.

In general, you should add water to your cactus when the top half-inch of soil is dry. When watering your cactus, moisten the soil, allowing it to absorb all of the water, and if it absorbs the water quickly, add more water until it comes out of the drainage holes of the pot. 

It is best to be aware of signs of over or under-watering. Check the soil every few days in the summer or spring and every couple of weeks in the winter.

Being able to determine how often and how much to water your cactus will ensure that it lives its best life and thrives under your care.

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Gareth Davies

Hi! I'm Gareth and I own Prickly Plant is the ultimate resource for everything you need to know about looking after your Prickly Plants. With over 10 years of experience selling and looking after plants, I'm passionate about sharing simple & understandable information for everyday people!