How Often to Water Cactus (10 Must-Know Tips)

How Often to Water Cactus

The modern life is a busy one. It’s only worse if you have multiple jobs or need to take care of the kids while still taking care of the house.

Even so, you want a plant. You want something green and natural in your house. You’d just like to get one that doesn’t need water every day in case you forget. That’s why you turn to the humble little cactus. 

Most people assume that caring for a cactus is an easy job. It is true that the cactus is a relatively low maintenance plant. They generally won’t need a lot of care, but there are still some things that you will need to remain consistent with. It won’t take long before you realize that there are some kinks to work out, though.

One of the most difficult things to work out for new owners is just how much and often to water them. They don’t take a lot of water, sure, but how much is too much? How much is too little?

You don’t need to water your cactus every day, but you still need to know what it needs. Otherwise, you risk damaging the health of your cactus. Understanding the specific watering requirements is key for any plant but even more so for the cactus. This is because the plant is a succulent, which means that it is able to store water in its roots and stems. 

A cactus can survive on very little water, but it won’t exactly thrive. There’s a big difference between the two. You’d be forgiven for thinking that a cactus would do just fine in a sunny spot with weekly watering. That’s similar to their desert environment.

It’s true that cacti can survive like that, but you need to offer them something extra in order for them to truly thrive in their environment. With that said, here’s a look at how often you need to water your cactus with our must-know tips of cactus care. In this article, we will go through all the steps you can make to ensure that you water your cactus the right amount. 

Top Tips for Cactus Care 

How Often Does a Cactus Need Water?

There are several different factors that go into how much water a cactus needs. The main thing to understand here is that there are many different kinds of cactus – each with their own wants and needs. 

The word “cacti” refers to the Cactaceae plant family. This umbrella term for cactus plants refers to a wide variety of different individual plants. These plants all live in different habitats with different needs. Of course, there are many typical cacti – such as the Ferocactus genus – that survive in harsh desert environments and don’t need much water.

That said, there’s also the Echinops cacti from South America and the orecerceus cactus of the Andes mountains. These cacti require more water than desert cacti. There are even jungle cacti like the epiphyllum genus. This cactus grows on trees instead of in dirt and prefers a cooler habitat with plenty of moisture. 

How much water your cactus needs depends on several factors, including; 

  • Their normal growing season 
  • The kind of soil, temperature, and environmental conditions it naturally grows in
  • The current soil, temperature, and environmental conditions it is currently being grown in 

During the growing season. Cacti will need more frequent watering. During the winter months, they can often go weeks without any water. 

How to Tell What Kind of Cactus You Have

Understanding how to care for your cactus begins with knowing what kind of cactus you have. Check the container that the cactus came in. It should have a sticker or a tag of some kind to identify the genus of cactus you have. It might also have some basic care tips. 

If you still can’t tell what genus it is, then you can get help from a nursery or online. Bring a photo of the cactus to a nursery and have someone identify it for you. Look up cactus photos online and try to identify yours – or post a picture on a gardening forum and ask for identification. If all else fails, then your local library might have some kind of reference book. 

Keep in mind that all cacti are different and they need different levels of sun, soil, and water. 

How Often Should Cacti be Watered?

Knowing how much water to give a cactus – and avoiding giving it too much or too little – is one of the hardest parts of cacti care. It’s the main reason that cacti fail to live up to their full potential. Unfortunately, you won’t get much help from a sweeping generalization of what your plant needs. With that said, we do have some more general guidelines to follow; 

  • Cacti require regular water and fertilizer during their growth season (typically from the spring to the fall). Be sure to give your cactus plenty of water during the driest and hottest months. 
  • Be sure to give your cactus time to dry out between watering sessions. You should allow the top of the soil to dry out completely before applying more water. A good water gauge helps to determine the moisture level of the soil. You could also just jam your finger into the soil and test it yourself. 
  • Adjust the amount of water you give if you keep your cactus in a pot. Plants in pots require extra water compared to plants kept outside in soil. 
  • Most plants enter a semi-dormant stage between fall and spring. They require less water during this time. If you live somewhere that gets more rainfall and water than the cactus would get in their natural environment, then don’t worry about watering it. 
  • Some people believe that cacti need some water during this dormant season, while others suggest they don’t need water at all during the winter. Be sure to carefully watch and test your cactus to accurately meet their water needs. 
  • Check the leaves and stems for changes that suggest the cactus is being stressed out by having too little – or too much – moisture. Not enough water can make a cactus look more skinny, pale, rubbery, and deflated. Too much water originally makes a cactus look healthy and strong, but eventually, the roots start to die off and rot, and the plant becomes pale and soft. Watch out for early warning signs to save your cactus. 
  • The water hardness for your area also contributes to the watering needs for your cactus. If you have hard water, then you should re-pot your cactus every few years in order to prevent salt from building up. 

How to Water a Cactus

Once you have figured out when to water your cactus, the next question becomes how much water to give. It can be a bit difficult to figure out how much to water your cactus. While there are several factors that go into determining just how often you need to water a cactus, there is, in fact, one golden rule of thumb that applies to most cactus variants; 

Many horticulture experts agree that cacti should be watered once a week for the hottest months. This is considered to be the best way to give your cactus the water it needs without overdoing it and soaking the roots. 

When the time comes to water your cactus, be sure to keep watering until the soil surrounding the cactus is completely saturated. When water drips out of the bottom of the pot through the drainage holes, then you’ve saturated the soil properly.

If you keep your plant in outdoor soil, then use a water gauge or test the water with your finger. By following these steps, you can be sure that your cactus will get enough water. 

Signs You are Overwatering (or Underwatering) Your Cactus

In general underwatering is far less harmful than overwatering your cactus. Underwatering can be quickly resolved through watering the plant in the proper manner. Below, we will go through some of the common signs that you may be underwatering your cactus. 

Signs of Underwatering

  • Plucky and shriveled appearance 
  • Cactus turning brown
  • Cactus looking dry and calloused

Many people tend to panic when they spot these signs; however, you can be reassured that underwatering does not tend to cause long-term damage to the cactus.

Luckily, an underwatered cactus can quickly start to heal once you start to adequately water it again. As a plant that is designed to withstand droughts, this is fairly understandable. 

Signs of Overwatering

Overwatering your cactus tends to be a far more serious problem. The signs of overwatering tend to be pretty clear, and they need to be dealt with urgently to save the cactus. A mushy appearance tends to be an obvious sign of overwatering. This occurs because the cactus simply runs out of space to store water.

By design, it is supposed to store water efficiently in case of dry conditions. It is not designed to hold too much water, and this is why overwatering can be so damaging. You will be able to notice a mushy texture when you poke your cactus. Below, are some of the key signs of overwatering. 

  • Cactus stems and leaves turning darker
  • Cactus base turning brown and black
  • Mushy and leaking
  • Signs of rot and decay

In most plants, over watering leads to root rot, and this is also true for cacti. In the case of a cactus, their sensitive root structures make them even more susceptible to root rot. Once root rot begins to set in, it becomes more difficult for the plant to properly absorb nutrients.

It will also mean that water absorption becomes affected. This results in a lack of water and nutrients throughout the plant which can cause a change in appearance. The leaves can begin to wilt, and in severe cases, even start falling off. It is essential not to overwater your cactus, and later in this article, we will go through the methods for treating root rot. 

How to Tell How Much Water a Cactus Needs if you Aren’t Sure on the Variety of Cactus You Have

If you still aren’t sure of the place of origin, proper name, or general care instructions of your cactus, then there are some questions that can help to determine the amount of water it needs; 

Does it Have Stems and Leaves?

In general, cacti plants don’t have leaves. Some of them do though. Thin cacti leaves mean that the cactus requires more water. Cacti that have a high surface-are-to-volume ratio (that is to say those with thin leaves) lose water faster than those with thick stems that have a lower area-to-volume ratio. 

Does it Have Spines?

Cacti are known for their spines. If yours has a lot of these spines then it might require less water than a cactus with less spines. These spines are a kind of modified leaf that cacti evolved to survive.

While they don’t have much water by themselves, they do help the cactus to preserve water by trapping air. The trapped air reduces evaporation by insulating the cactus. Spines also offer some shade to a cactus to reduce temperature and water loss. These spines are effective at grabbing moisture out of the air too. 

What is the Stem Like?

If your cactus has a solid stem then it’s probably very good at conserving water by itself. The stem is where a cactus stores its water. Whether your cactus has a round globular shape or a cylindrical columnar shape it has a low surface-area-to-volume ratio that makes it effective at storing and preserving water.

If your cactus has a ribbed stem then it means that it can expand or shrink with water based on how much there is. 

How Big is It?

In general, the smaller a cactus is the less water it needs. 

Is it a Succulent?

The cactus is a sub-species of the succulent variety of plants. Succulents are basically plants that store water in their stems or leaves. While just about every cactus is a succulent, not every succulent is a kind of cactus. 

Cacti are generally the most efficient succulents at water storage. Catacaeae plants have stems to store water, hairy coverings or spines, and barely any leaves. 

Other succulents generally have leaves. Though the line between what counts as a cactus and what counts as a succulent gets a little blurry because not all succulents have leaves. 

Fertilizing a Cactus

There’s a bit more to caring for a cactus than just watering them. They also require some nutritional fertilizer as well as water. 

While cacti are more resilient than other plants they still require plenty of nutrients to help them grow. Those nutrients come in the form of different fertilizers. The growth season for cacti tends to be during the humid and warm summer months. 

With that said, there are some species of cacti that grow during winter and are dormant in the summer. That’s why you need to know what kind of cactus you have. While you should still water a cactus during their dormancy, you shouldn’t worry about giving them fertilizer.

Many cacti species prefer to be fed a lot of small meals instead of one big one. Cacti like low-nitrogen fertilizers. Aim to find one with more phosphorous than nitrogen. 

How Much Sun Does a Cactus Need?

The light requirements for different cacti is, well, different. In general, they require around four hours of direct sunlight each day at a minimum. Keep your cactus near an east-or-south-facing window if you keep them indoors.

They like to be evenly exposed to the sun too, so you’ll want to rotate your plant every so often so all of it gets a little sun.

Cacti like temperatures between 45F and 85F. High temperatures allow the plant to grow faster and use more water. In general, higher temperatures and increased airflow increase evaporation which means that you will need to water your cactus more when they are present.

In the summer months, it is important that you check for dryness on a more regular basis. 

Humidity can also have an impact on watering requirements. Evaporation also increases in arid conditions. It is a good habit to maintain consistent humidity levels and check them regularly.

Even though cacti prefer arid conditions, they can still thrive in a humid environment. However, it does mean that you will have to keep an even closer eye on soil dryness. 

What Kind of Pot Should be Used with Cacti?

When planting and re-planting cacti in a pot, you should use one that is just big enough for them. This ensures that the roots dry out fast and stay dry. You should also consider adding some holes to the bottom of the pot so that it drains even faster. Draining moisture is essential in keeping a cactus healthy.

This is why Terracotta pots are preferred to plastic pots. Plastic pots tend to trap excess moisture, whereas Terracotta pots are porous which means that water can slowly pass through.

Pots with a large number of drainage holes are ideal because they allow water to pass through without being trapped. It is possible to grow a cactus without drainage holes, however, this requires much more care in how to water the plant. 

What Kind of Soil do Cacti Like?

Look for potting material that offers excellent drainage, but make sure you get a porous soil. If your cactus doesn’t have spines then it would like to live in soil that has more humus in it, which is basically organic material that helps it grow. It is important to always use fresh soil when you replant your cactus. 

How to Tell When a Cactus Needs Water 

There are a few ways that you can definitely tell that your potting mix is dry. This dryness will indicate that your cactus needs water. The soil should always be completely dry before you water, regardless of the season or growing phase.

However, figuring how to properly check the dryness can prove to be a bit complicated. You can poke a finger into drainage holes to check for moisture. Alternatively, you can use your finger to poke into the top few inches of potting mix.

If it feels perfectly dry right the way down, then you can start to water. However, if the soil feels wet and clings to your finger, then this indicates that watering is not required. 

Treating Root Rot in a Cactus

We explained above that the main issue with overwatering tends to be the development of root rot. If you think that your cactus may have root rot, then there a few ways that you can check for certain.

The only way to check is by thoroughly inspecting the roots, and to do this you will need to remove the cactus from the container. Healthy roots will be white in color, and the presence of dark roots indicates that there may be a root rot problem. A mushy texture can also signal the presence of root rot.

Root rot can easily lead to the death of a plant, however, if there are still white roots visible then you can treat it and save the plant. The best way to treat root rot is by directly removing the infected roots with the use of clean shears.

It is important to thoroughly clean the shears both before and after to avoid spreading root rot to any other plants. Once you have removed all infected roots, the cactus can be replanted.

It is important to use a well-draining potting mix and allow the plant to settle for a week before you begin watering. The previous soil should be completely removed, and you should use fresh soil when replanting your cactus.

Common Mistakes When Watering a Cactus

Now, that you have learnt the best tips for watering a cactus, we will go through some common mistakes so that you can steer clear of them. Most of these are fairly common for new cactus owners since it can be a learning curve getting everything right. 

Underwatering/Overwatering

By far, the most common mistakes people tend to make are either underwatering or overwatering their cactus. As we stated above in the article, learning your specific variety will help you avoid this.

Overwatering causes root rot whereas underwatering can cause drying. It is essential to resolve these problems before they get serious. Fertilizer is another substance that can be overused and underused. We recommend using diluted fertilizer during the growing season. 

Using Incorrect Container

Another common mistake that tends to occur is using the wrong container.  It is vital for cacti to be stored in containers that have adequate drainage holes to prevent root rot.

Technically, it is possible to plant cactus in a container without drainage holes, however, this requires you to be incredibly careful with how much you water the plant. In our opinion, the best type of container for cactus is a Terracotta since it allows your cactus to thrive easily. 

Using Incorrect Growing Medium

The ideal type of growing medium for cactus is one that drains quickly. However, many owners simply don’t bother being picky with the medium because of the belief that a cactus can thrive in all types of conditions.

However, picking the wrong soil can lead to a range of problems such as root rot. Therefore, it is crucial to buy a potting mix that has been specifically designed for cacti or succulents. 

Using Incorrect Water Source

Another mistake that people can make is using the wrong type of water source. Most tap water will be fine, however, certain sources contain high levels of fluoride and chlorine. These are chemicals that can damage a cactus.

If you see your cactus in poor health, and can’t figure out the cause then it can be worth giving them distilled water or collected rainwater. If they recover, then you will know that the source of the problem was the water that you were giving them. 

Summary

The truth is that your cactus might require more water than you think or less than you think. It is important to be sure of this rather than experimenting.  Even so, they are still much easier to care for than some other plants.

You shouldn’t be put off by the watering requirements or the care requirements. Don’t worry about getting a cactus now you know the truth about caring for them. They still make for interesting and excellent floral companions.

You will now have a much better idea of how to properly water cactus so that they can thrive. By following these guidelines closely, you will have a happy and thriving cactus. 

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