Watering cactus plants can be a big struggle, and many gardeners end up overdoing it. So in this post, I’m going to show you how to tell when they need it, and how often to check so you do it the right way!
Despite being drought tolerant and low maintenance, there is a right and wrong way to water a cactus.
Learning how to do it properly is essential, as too much moisture can quickly kill them.
In this guide I’ve shared everything you need to know about how to water a cactus. Learn when and how, plus the signs of over and under watering.
Cactus Watering Requirements
As I’m sure you already know, cacti don’t require much water because they’re great at storing it in their leaves and stems.
This allows them to go for long periods of drought in their natural desert habitat. In fact, overwatering is the number one mistake gardeners make.
Too much can lead to root rot and other issues. So it’s usually better to err on the side of caution, and give them less rather than more.
When To Water Your Cactus
How frequently your cactus needs water depends on several factors, like time of year, temperature, light exposure, and much more.
So I never recommend doing it on a set schedule. Sticking to a regular calendar is a common cause of overwatering.
Instead, you should get into the habit of checking the soil to determine the right time.
How Do I Know If My Cactus Needs Water?
The best way to check if your cactus needs water is to use an inexpensive moisture gauge, or by touch. The soil should be completely bone dry before adding more.
If the meter reads dry (at 1 on the scale), or you don’t feel any moisture when you stick your finger down at least 2”, then it’s time for a drink.
The pads or barrel may start looking shriveled or wrinkled, and feel soft to the touch when it’s dehydrated.
However, this is also a sign of overwatering. So checking the soil moisture level should always be your #1 indicator to know when it’s time.
How Often Should You Water A Cactus?
How often you water a cactus depends on many factors. Whether it’s indoors or outdoors, different seasons, your climate, and the size and variety all affect how much it needs.
Smaller cacti will dry out faster than larger ones. Mature plants may go a few months or more without needing a drink, while little ones will require it more often.
They’ll lose moisture faster in pots outdoors, especially in direct sun. Occasional rain is often plenty for those planted in the ground.
They’ll also need more during warmer months, and less during cool seasons.
How Often To Water Cactus In Summer
Heat, intense sun, and active growth mean that most cacti will need to be watered more often during the summer.
Smaller plants will require more frequent drinks, but larger ones often need additional moisture during the summer as well.
The best approach is to check the soil once a week during the spring and summer months to determine when it’s time.
How Much To Water A Cactus In Winter
Winter is a rest or semi-dormant period for many cacti, so they won’t need to be watered as often.
During the coldest months, it’s normal for smaller ones to go several weeks without needing a drink. Larger specimens can often go all winter without any added moisture.
Because of this, overwatering is a huge problem during the fall and winter. To avoid overdoing it, let them dry out more, and always use a moisture gauge or your finger to check the soil.
How Much Water Does A Cactus Need?
It’s difficult to quantify the exact amount of water your cactus will need. It’s always better to use less rather than overdo it.
A good approach is to water deeply after the medium has dried out completely.
Run it through the container until the soil is wet, but not soggy or saturated. Be sure to allow all of the excess to drain from the bottom holes, and never leave the pot soaking in it.
Overwatering a cactus will cause root rot, which can quickly kill your plant. There are many signs to watch out for that indicate they’ve had too much.
- Overly plump leaves, pads, crown, or barrel
- Sudden rapid or uneven growth
- Color changes, like yellowing or browning
- Brown or black mushy spots
- Leaf, pad, or spine drop
- Rotten, soggy roots or stems
- Plant is shriveling
If yours has started to show any of these symptoms, learn how to save it from rotting here.
Under Watering Symptoms
Believe it or not, it actually is possible to under water a cactus. They will begin to display signs of thirst if left in bone-dry for too long.
Be on the lookout for these common indicators. But be careful because many of these are also signs of overwatering, which is a much more common problem.
- Wrinkled or wilted leaves, pads, or barrel
- Dull or faded coloring
- Dry or brittle spots
- Stunted growth
- Soil pulled completely away from the pot
- Plant turning brown
How To Water A Cactus
There are two approaches you can take when watering a cactus – from the top or bottom. I’ve discussed the pros and cons of both here.
Watering A Cactus From The Top
Watering a cactus from the top is the best method, and the one I recommend. It’s a good way to ensure that you don’t overdo it.
Slowly pour it over the potting medium, so it is moistened evenly and thoroughly. Do not pour it over the top of the plant, because if it sits on there too long, it could cause black spots or tip rot.
When it begins to flow from the bottom of the pot, you’ve added enough. Discard any that drains out, and never leave it soaking.
Bottom Watering A Cactus
Though bottom watering is possible for cactus plants, I don’t recommend it. There’s a much higher risk of overwatering because you can’t tell how much has been absorbed by the rootball.
The only time I would do this is if your plant is severely dehydrated, and the soil will not absorb any moisture when you pour it over the top.
Be sure to only leave it soaking long enough for the medium to become moist half way up, and never until it’s soggy. Use this technique with great caution.
Here I’ve answered some of the most commonly asked questions about how to water a cactus plant. If yours isn’t on the list please add it to the comments section below.
Should I spray my cactus with water?
No, it’s never a good idea to spray a cactus with water. They have very low humidity needs, and moisture left sitting on them can cause rot and other diseases.
Do you water cactus from the top or bottom?
You can technically water a cactus from either the top or bottom. However I recommend top-watering because it is more controlled, and you’re less likely to overdo it.
How often should I water my small cactus?
There is no schedule for how often you should water a small cactus. But they tend to dry out faster than larger ones, so check weekly, and moisten the soil only when it is dry.
With these tips on how to water a cactus, even a beginner can easily learn how to keep them healthy and thriving. Just remember to err on the side of under watering, and you’ll be good to go.
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More About Houseplant Care
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Share your tips for how to water a cactus in the comments section below.