When you bring home your first cactus, watering can be slightly confusing. Since most cacti originate from dry, arid desert environments, you may think that they like infrequent watering, but there’s more than meets the eye with these prickly cactus plants.
They do like drier soil, but cacti still need some moisture, especially in their growing season. You’re probably wondering how often should I water my cactus?
To grow a happy cactus, you need to know more than just how often to water it. There are many things to consider for watering these succulent plants, but you’ll know everything there is to know after reading this post.
How Often Should You Water a Cactus?
Let’s dive in because there are quite a few points that need to be discussed. When growing a cactus, water is just as important as it is for other houseplants.
How Much Water Do You Give a Cactus Plant?
This is dependent on many factors, including season, growing location, the soil you’re using, and the plant’s size relative to the pot. So, there isn’t a clear-cut answer to how much water a cactus plant needs. However, all these considerations are explained below, giving you clarity regarding this question.
While this may be a nuanced question, you should still pay close attention to the appearance of the cactus. If it has a pale color and becomes wrinkly, then it needs to be watered more frequently.
If you’re unsure, it’s best to side with caution and slightly underwater rather than overwater. The plant can quickly bounce back from underwatering, but overwatering can cause permanent damage.
Can a Cactus be Overwatered?
Yes, it’s possible to overwater a cactus, and doing so is more severe than underwatering because the effects can be irreversible. You may be overwatering your cactus if you see any of the following:
- Rot or decay of the plant
- Leaves and stems start wilting and change color, turning brown or black
- The base of the plant turns black
Root rot is something that affects all plants, and this can set in if you overwater your cactus. Once the rot starts, the roots will not be able to absorb water and nutrients. This is why leaves and stems change color and droop.
If you suspect your plant has root rot, you need to remove it from the pot and check the roots.
To remove the plant, hold the plant’s base where it meets the soil with one hand and flip the pot upside down with your other hand. This will make it easier for you to remove the plant from its container.
The roots should be white and pliable, but if root rot has set in, you’ll notice segments of the root-ball are brown and mushy.
If there are only a few sections of rotting roots, cut them off with sanitized shears, remove the contaminated soil and sterilize the empty pot with bleach. Then repot the plant with new soil.
When to Water a Cactus Cutting
Due to the small size and limited root structure, a cutting can be watered less frequently than an older cactus. However, when you pot the cutting, it will need a soil drench.
Once you’ve potted the cutting, refrain from watering it again until the first 2 centimeters of topsoil is dry.
This is to ensure that you don’t overwater it and stunt its growth. Once the soil is dry enough, drizzle water around the plant’s base until the soil is damp at a depth of about 3 to 5 centimeters.
Watering a Cactus After Repotting
Repotting is only necessary after about 3 to 4 years, but once you’re ready to do this, make sure to use a good potting mix that drains well.
After the transplant, you’ll need to water the plant thoroughly. Soaking the container with water after the transplant gives the cactus plenty of moisture to absorb nutrients, reducing transplant shock.
It’s still vital to let the water drain out the bottom to let the soil dry out. Don’t try to save the excess water by placing a dish or tray under the pot. Doing this will increase the likelihood of root rot.
Watering a Cactus in Spring and Summer
When determining how often to water a cactus indoors, you must take into account each season. Due to the warmer temperatures in spring and summer, the soil will dry faster.
The growing location also plays a significant role here. The hotter the room, the more water the plant will need.
Soil that drains well is essential because it will allow for excess moisture to exit from the pot, keeping the roots healthy in all seasons.
During these warmer seasons, cacti need more moisture, so watering should occur once every 10 to 14 days.
However, if you live in a hot, arid area, you may need to water the plant at least once a week. Check the soil 2 to 3 days after its watering to see if once a week is adequate or if you need to water more (or less) than once a week.
Watering a Cactus in Autumn and Winter
The growing season occurs from spring to summer, so the plant’s growth rate decreases in autumn and winter. Due to this, it needs less frequent watering because it stops growing once it detects a drop in temperatures.
You’ll only have to water cactus once or twice a month during winter, as the cooler temperatures retain soil moisture.
Over autumn, if it’s warmer than 5ºC, you can water about once every 10 days. Otherwise, follow the same watering schedule as you would in the winter months.
During these seasons, you must check the soil moisture before each watering. Cacti can handle relatively dry soil, although some soil moisture is still required.
Humidity affects the growth of plants, so when using central heating during winter, the humidity levels will decrease, increasing the soil’s evaporation rate.
A good strategy is to invest in a portable humidifier to keep your plants at the correct humidity level if you have many houseplants.
How to Water Cacti Indoors
Cacti are succulents and store water in their leaves and stems, so the worst thing a plant parent can do is overwater them. As mentioned above, overwatering causes root rot, which is best to avoid. Underwatering is less serious but can still damage the plant as the roots dry out, stunting the plant’s growth.
As previously mentioned, how often you water the plant depends on the season, but the watering method remains the same regardless of the season. It’s best to drench the soil until you notice water draining out of the bottom of the pot.
From an evolutionary standpoint, most cacti receive very little rain in the wild as they are desert plants, but when it rains, it pours. That’s why it’s essential to drench the soil all the way through with each watering.
Cactus Watering Criteria
The following criteria will affect how much and how frequently you’ll need to water your cactus.
Once a small cactus has developed its root-ball, it will need to be watered more frequently than older cacti due to its greater growth rate.
As the cactus gets larger, its surface area to volume ratio will decrease. This decreases the evaporation of water from the plant’s surface, meaning it requires water less frequently than younger cacti.
Type Of Soil Determines How Much Water The Plant Needs
One of the most crucial aspects of growing cacti is using superb soil. These plants grow well in porous, sandy potting soil that drains well. Using this type of soil will allow excess moisture to exit the pot once the cactus has absorbed enough water.
This gives the cactus plants adequate aeration and drainage. The organic matter in the soil is also essential because it provides the roots with moisture and improves their ability to dry.
Type and Size of the Containers You Use
There are various types of pots that you can choose from. Each type of container determines whether you’ll water more frequently or not.
These pots are hardened by clay. The unglazed ceramic containers allow water to drain from the walls and help absorb the soil’s moisture. These types of pots are an excellent choice for cacti, as they like fast-draining soil.
The glazed ceramic pots don’t absorb moisture, so the soil will take longer to dry. When using these pots, you must check the soil’s moisture before you water the plant.
An advantage to these containers is their suitability to indoor environments, and they protect the plant from sudden temperature changes.
Like ceramic pots, terracotta containers are made from clay and are unglazed. They are relatively porous, drain water effectively, and absorb moisture through the sides.
Not only this, but they are lighter and cheaper than ceramic pots, making them an excellent choice for growing cacti.
Plastic pots are the most common because they are cheap, durable, light, and come in various designs and colors.
The downside to these pots is that they don’t drain fast, so if you use them, you’ll likely water your cactus less to prevent root rot.
These durable pots can be molded into many shapes and sizes. However, water doesn’t drain well from these pots, so if you’re growing desert cacti, you shouldn’t use this type of pot.
If you are already using this pot, only water the plant when the soil is dry to ensure you don’t overwater.
These pots are highly durable and resistant to cold temperatures. However, if you live near the ocean, they will likely start rusting after a while, but you can coat them to prevent this.
A significant downside to these pots is that when under direct sunlight, they will absorb a lot of heat, burning the cactus.
Most metal containers don’t come with drainage holes, so it’s best to drill holes at the bottom if you plan on using one. It would be best if you also watered when the soil is dry to avoid bacterial infections of the root-ball.
That being said, metal pots are not ideal for cacti plants, and you’re better off using another type.
Wood pots don’t crack with age, so they’re great for growing cacti outdoors. They also hold moisture well and are slow draining.
However, roots can rot quite quickly if these pots receive too much water.
If you plan to use a wood container, line the inside of the pot with plastic to minimize root rot. If you’re using a wood pot already, water the cactus less frequently, as the container holds moisture for longer.
Using The Right Type of Water When Watering Cacti
Believe it or not, but the type of water you use can also affect the health of your cactus.
This is treated with potassium or sodium to remove magnesium and calcium. If you use soft water with high sodium levels, the health of your cactus can deteriorate due to sodium buildup in the soil.
This dehydrates the plant and decreases its ability to absorb nutrients, stunting its growth and is a reason why plants wilt.
Hard water has higher levels of calcium and magnesium, which can leave permanent markings on the cactus due to buildup in the soil.
Watering your plant with hard water can also significantly affect its growth and overall health.
If buildup occurs, you can treat it by repotting the cactus with new soil, but it’s recommended that you only transplant your plant every 3 to 4 years.
This is the best type of water cactus needs as it contains all the necessary minerals that cacti need. Rainwater may not be available year-round for everyone, but you can store it for later use.
You can also dilute tap water with rainwater to minimize the buildup of salts. Eventually, you’ll need to transplant the cactus once buildup occurs over time.
Treating Mineral Buildup
When you notice mineral buildup, you can treat it by mixing 1 tablespoon of vinegar with rainwater or distilled water (1 part vinegar to 4 parts water). Dip a cotton ball in this mixture and wipe away the stains on the plant.
You should also remove the first few centimeters of topsoil affected by the buildup and replace it with new soil. If you’re repotting, you can wipe down the empty pot with this mixture to dissolve any leftover minerals in the container.
How Often Do You Water a Cactus – Answered
Using the above information will help you develop a proper watering schedule and reduce the likelihood of damaging your cactus, which will maximize the plant’s growth and overall health.
However, determining how to water your cactus correctly can take some time. But doing so will give you a solid understanding of what is best for the plant, and you’ll have no problems growing household cacti in the future, which is so worth it.
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