How To Water Cactus Plants

Spread the love

Cactus plants are some of the most popular houseplants around the world thanks to their low maintenance requirements. In fact, many cacti tend to thrive on neglect and this is something that must be kept in mind when it comes to watering your plants.

Cacti originate from dry, desert regions where they’ve learned to adapt to their harsh environment. Living in the desert means that cacti are exposed to long periods of dry weather interspersed with short and heavy bursts of rain.

This adaptation should give some clues on how to best water the cacti that we grow at home so that they will continue to thrive within their more controlled environment.

When Should You Water Your Cactus?

The most important lesson that you can learn about cactus plant care is not to overwater them. Essentially, it’s far better to underwater your cactus than to overwater it.

The soil or potting mix that your cactus is growing in needs to be allowed to dry out completely before you give the plant any additional water. This, in effect, will simulate the natural environment that these plants grow in. 

There is no steadfast watering schedule that can be applied to cactus plants as it depends entirely on the size of the pot, the temperature and humidity level, and the season.

For example, in summer, your cactus will require watering more frequently because the soil will dry out faster. On the other hand, in winter, the plant will be dormant and will require very little water during this time.

So, if we consider a typical scenario where your cactus is in a small to medium pot with a temperature range of around 60 to 75 degrees Fahrenheit (16 to 24 degrees Celsius), it will most likely need to be watered every 10 days in summer and only once a month in winter.

This leads us to the factors that can affect how long the soil takes to dry out.

Location Of Your Cactus

Whether your cactus plant lives indoors or outside is an important factor to consider. Your indoor environment will likely be more controlled than the weather outside, especially in the different seasons.

For example, in summer you may have the air conditioning turned on indoors. While this will keep the temperature cooler, it will also dry out the air. This could have an effect on how quickly the soil dries out in your potted cactus.

Of course, a cactus that lives outside in summer will have dry soil much faster than one that is kept indoors and well away from the air conditioning.

The Temperature And The Humidity Level

It goes without saying that warmer temperatures will result in the soil drying out faster while cooler temperatures will allow the soil to stay moist for longer. Higher humidity levels are also likely to keep the soil damp for longer compared to air that is fairly dry.

The Amount Of Direct Light The Cactus Gets

Cactus plants that are grown in direct sunlight will have soil that dries out much faster than those that are only exposed to indirect light. Even plants that sit on bright windowsills will dry out faster than those that are located elsewhere in the room.

The Different Seasons

As we’ve already discussed, during the summer your cacti will need more frequent watering than during the colder months. This is primarily because most cacti enter a period of dormancy during the winter when they’re not even using much of the water that they have stored in their stems.

The Soil Mix That Your Plant Is Growing In

Ideally, you should have your cactus growing in a nice, open soil mix that is completely free-draining. That’s why a standard potting mix is not really good for cacti because it can have the tendency to hold moisture for longer periods of time.

Always remember that cactus plants need a period of dry soil before they are watered again.

The Size Of The Container

It’s just common sense that the soil in small containers will dry out much faster than that in larger ones. So cacti that are grown in tiny pots will need more frequent watering than those in really large ones.

The Presence Of Adequate Drainage Holes

This is another important aspect of good cactus care. All cacti should be grown in pots that have adequate drainage holes. The roots of your plant should never be allowed to sit in water as this will definitely cause the plant to rot.

If you grow your cacti in terracotta pots, you’ll find that the soil will dry more quickly too. This is because terracotta and unglazed clay pots are porous and the water can evaporate through the sides of the pot.

The Cactus Variety

Some cactus varieties will need more frequent watering than others. Desert cacti are adapted to periods of dryness and will survive quite happily if they miss a watering or two.

On the other hand, forest cacti species such as the Christmas cactus, need more frequent watering as they’re adapted to living in a more sub-tropical climate with more frequent rains and a higher level of humidity.

The Size Of The Cactus

It’s common to think that larger cacti will require more water than smaller ones. However, quite often the smaller cactus will be more actively growing and will need more frequent watering, especially if it’s living in a smaller pot. 

So, although larger cacti will require a higher volume of water at each watering, smaller plants are likely to need watering more frequently.

How To Determine If Your Cactus Needs Water

When it comes to when to water cactus, with most cactus species, you only want to water your plant when the soil is completely dry. But, how do you determine this? There are several methods that you can utilize to test the moisture level in the soil.

Feel The Soil With Your Finger

In most cases, it’s easy just to poke your finger into the soil to determine whether it’s damp or dry. Just poke your finger into the top two or three inches of soil and check whether it’s dry.

If your finger comes out clean and there’s no soil sticking to it, then it’s safe to determine that your plant needs some water.

As an alternative, you can also poke your finger into one of the drainage holes at the base of the pot to see whether the soil at the base is dry.

Check The Moisture In The Soil With A Wooden Skewer

Similarly, you can poke a wooden skewer or popsicle stick into the soil for around 2 to 3 inches. If there’s no soil stuck to the skewer when you pull it out, then you can assume that the soil is dry.

On the other hand, if there appears to be some damp soil clinging to the stick, then wait another day or two before checking again.

Use A Moisture Meter Or Probe

Sometimes, the pot can be too small to poke your finger or another implement into it, or maybe you’re not confident that you can tell if the soil is dry. In this case, you can purchase a moisture meter at your local garden center.

Attached to the meter is a probe that you just stick into the pot all the way down to the bottom if possible. The meter will then give you a digital readout on the level of moisture in the soil.

The Best Method For Watering Cacti

Now that you’ve determined that your cactus plant needs some water because the soil has dried out completely, what is the best way to water your plant?

Basically, there’s only one recommended method for watering cacti and that is the “Soak and Dry” method. This method simulates that plant’s natural environment and guarantees to provide your plant with adequate amounts of water without giving it too much.

Here’s what to do:

  • Either take your plant to the sink or basin or take it outside.
  • Use a watering can or jug to thoroughly water the soil in the container. Avoid wetting the plant when you do this.
  • Stop adding water once the excess starts to drain out of the holes in the bottom of the pot. This ensures that the soil is entirely moist right throughout the pot.
  • Leave your plant to drain completely before placing it back in its original spot.

If your pot is too large or awkward to move, you can water it where it sits. Most likely, you’ll have a saucer sitting under the pot if this is the case.

  • Just water the soil of the plant until you see some water draining into the saucer and then stop immediately. 
  • Remove the saucer after about half an hour or so and empty it before replacing it under the plant.
  • Check in another hour or so to ensure that there is no water in the saucer. If there is, empty it a second time.

You might also have small cacti in ceramic pots that have a plug inserted into the bottom that covers the drainage hole. Here’s how to water these.

  • Take the pot to the sink and remove the plug from the drainage hole.
  • Water the soil until you see water coming out of the drainage hole.
  • Let the plant sit on the side of the sink for an hour or so to ensure that all the excess water has drained away.
  • Replace the plug and return the plant to its original position.

Remember that you should never mist your cactus plant as cacti don’t appreciate water sitting on their stems or modified leaves for any period of time. Therefore, always water the soil at the base of the plant and avoid getting any water on the plant itself.

Also, avoid just giving your cactus a splash of water every now and again. This is not what your plant needs and it won’t thank you. If you want your plants to thrive and be super healthy, always use the soak and dry method when it’s time to water.

How Often Should You Water Your Cactus?

So how often do you water a cactus? The answer is actually quite simple!

You should only water your cactus when the soil has dried out completely. For this reason and many of the other factors that we’ve already discussed, there’s no set schedule for how often you need to water your cactus.

Luckily, most cacti are fairly forgiving if you forget to check, once in a while, whether your plant needs water. As a general rule, during spring and summer, check the soil that your plants are growing in around every 10 days or so.

If the soil is dry you can water your cactus. If the soil is still a little moist wait another couple of days before checking again.

In winter, however, you really only need to check your plants once a month or so because they won’t be using up much water while they’re not actively growing.

What Type Of Water Do Cacti Prefer?

If at all possible, your cacti will definitely benefit from using rainwater or distilled water. In essence, rainwater contains certain minerals that tap water does not. In fact, if you have an outdoor garden, you might notice that your plants look so much healthier after they’ve had a bit of rain even though you water from the tap on a regular basis.

In the event that you don’t have a rainwater tank or aren’t able to collect some rainwater for your plants, distilled water is second best. This can be as simple as filling a jug or glass jar with some water and leaving it to sit for a day or two so that any of the harsher minerals can dissipate.

Should You Water Your Cactus After Repotting It?

For most houseplants, it’s common to give them a good drink after repotting them. However, this is not the case for cacti.

The repotting process for cactus plants is such that it tends to disturb the root system no matter how gentle you are. In this instance, the roots need time to strengthen before they’re ready to start absorbing moisture and nutrients again.

Therefore, you should wait a couple of days after repotting your cactus before you give it any water. If you water the plant straight after repotting, you could encourage the growth of root rot.

What Are The Signs Of An Underwatered Cactus?

Sometimes, it’s easy to forget to check to see if your cactus needs water. These plants are so low-maintenance that their water needs can sometimes be overlooked.

But, don’t worry if this happens because your plant will show you signs that it would really like a drink. Here’s what to look out for:

  • Stems and leaves that look a little shriveled or deflated.
  • Discoloration of the leaves or stems.
  • Leaves that look wilted but are not soft and mushy.
  • Leaves that look like they’re drooping.

When you notice these signs, don’t panic. Just give your plant a good soak, remembering to let all the excess water drain away. Within just a few days, your plant will perk up again and be back to normal.

What Are The Signs Of An Overwatered Cactus?

Overwatering should be avoided at all costs because this could actually be detrimental to the survival of your plant. As stated earlier, it’s far better to underwater your cactus than it is to overwater it. 

Here are the signs to look out for:

  • The leaves and stems appear shrunken and are soft and mushy to the touch. This is because the cactus has absorbed all the moisture that it can and has run out of space. This causes the cell walls to rupture and makes the stems and leaves feel mushy.
  • Black spots appear on the stems and leaves.
  • You start to see evidence of rot or decay.

Unfortunately, once root rot has set in, there’s not much you can do to save your plant. Your best option is to save some of the healthy stem sections and use them to propagate a new plant.

Can You Save A Cactus That Has Developed Root Rot?

If your overwatered cactus has developed root rot, in some instances, there is a possibility that you can save it. Here’s what to do:

  • Take the plant out of the container and remove the soil from the roots.
  • Inspect the root system to see if there are any healthy white roots instead of black, brown, or mushy ones.
  • If you do see some healthy roots, use clean secateurs to cut away all the damaged roots, leaving only the healthy white ones. Disinfect the shears and also cut off any damaged stems that might be present.
  • Replant the cactus into a clean pot with some fresh new potting mix.
  • Let it settle for around a week or so before giving it water.
  • Discard the contaminated soil and plant parts.

Avoid These Mistakes For A Healthy Thriving Cactus

If you’re totally new to cactus growing, it’s understandable that you might make some mistakes when it comes to watering your plant. Here are a few things to avoid.

Over Watering Or Under Watering

Now that you understand how to tell if your cactus needs a drink, you should easily be able to avoid overwatering or underwatering your plant. 

Just remember to only water your plant when the soil is completely dry and to check your plant around every 10 days in summer and around once a month in winter.

Not Adding A Little Fertilizer To The Water During The Growing Season

Like all plants, cacti do benefit from some additional fertilizer during their active growing season. Adding some liquid feed to the water during the warmer months will give your plant a boost and it will reward you with lots of healthy growth.

Using A Pot That Is Too Large Or Has No Drainage Holes

In general, cacti like to be quite confined when grown in a pot. Therefore, choose a container that is just a little larger than the rootball of the plant. This also ensures that there is not a lot of excess soil that can be allowed to remain damp.

In the same vein, you should only use pots that have adequate drainage holes, Not doing so will only set you up for failure as it’s very difficult to not overwater plants grown in pots without adequate drainage.

Using Incorrect Potting Mix

For your cactus plant to be happy and healthy, you need to choose a mix that is extremely free-draining and not a general potting mix. Therefore, consider purchasing a special mix that is specifically designed for cacti and succulents.

Using Water That Is Contaminated With Minerals And Chemicals

More often than not, our tap water has been treated with certain minerals and chemicals to make it safe for us to drink. However, all these additives are not ideal for cactus plants.

It’s much better to water your cacti with rainwater or even distilled water for optimal health and growth.

Conclusion

Learning how to water your cactus correctly is crucial to its survival. Remember that it’s far better to underwater your plant than it is to overwater it.

The golden rule is to always wait until the soil has dried out completely before giving your plant some water. Then, give it a good soak and let all the excess water drain completely away.

And finally, never ever let the roots of your cacti sit in water. This will lead to root rot and the possible death of your plant.

Once you remember and practice the golden rule, you should have no trouble keeping your cactus alive and thriving for many years to come.