How to Water Cactus for Optimal Growth

Cacti are beloved for their easy-going nature and tolerance of neglect. However, when it comes to watering cactus plants, there are still a few ways to get it wrong. In this article, I’ll explain exactly how to water cactus plants, including the primary considerations to be aware of, when to water, how to water, the best types of water to use, and remedies for over and underwatered cacti.

How to Water Cactus – The Main Considerations

If you have been tending plants for some time now, then you already know that watering is not as easy as it sounds. Yes, it’s easy to do, but there’s a lot more to consider than adding water whenever and hoping for the best.

You also need to think about the following factors that affect the watering needs of a cactus plant.

Your Plant’s Location: Indoor vs. Outdoor

One factor that often gets overlooked when watering any plant is its location. Plants grown indoors require slightly different watering requirements from those grown outdoors since their growing conditions vary.

Temperature & Humidity

Temperature and humidity largely contribute to a potted cactus plant’s watering needs. High temperatures make the soil dry out faster, while colder temperatures help retain soil moisture. The more quickly the soil dries, the sooner you’ll need to water.

Light Conditions

Cacti in direct sunlight and those planted in the shade have different watering needs. When plants are in direct sunlight, the soil tends to dry quicker, thus requiring more watering. Cacti in the shade or partially lighted areas, as when they are grown as indoor plants, can retain soil moisture much longer.

The Seasons

Most plants, including cacti, grow actively during warmer seasons (called the growing season). They require a deep soak to remain vigorous as they grow.

In fall to late winter, most desert cacti are dormant or in a ‘resting period’. During this period, they only need occasional watering or when the soil dries out completely.

Soil Mix

The soil mix also plays a crucial role in determining your cactus’s watering needs. Soil types and conditions respond differently in terms of moisture absorption and water retention. Loose, well-draining soil is best for a cactus plant because it won’t hold excess moisture, resulting in root rot.

Heavy and compact soil is something you should try to avoid if you want a thriving plant. This type of soil is not well-draining and often leads to soggy conditions.

Potting Container Size

The size of a potting container also has an influence on watering succulents. Generally, small and shallow pots tend to evaporate and drain water faster than bigger and wider ones. Because of that, cacti in small containers need more frequent watering than those planted in bigger pots.

Drainage

Drainage is another factor that significantly affects the process of watering cacti. Cactus grows best in soil with excellent drainage. Occasional overwatering will not be an issue with good drainage, since the soil can drain away any excess water.

Cactus Types

There are many cactus species available. Most of them don’t have true leaves, while others do. Some are small, and some are large. There’s also variance between those that will happily thrive with infrequent watering and those that need a consistent watering schedule (such as Fishbone cactus or the succulent plant Christmas cactus).

Such differences affect the plant’s watering needs. For instance, smaller cacti need less water than bigger ones. On the other hand, those with thinner leaves require more water than a desert cactus with thick modified leaves or stems.

Thus, knowing the type of your cactus will help to determine how much water it needs as well.

When to Water a Cactus

Every plant in the Cactaceae botanical family is different. The watering needs of these plants depend on their characteristics and external factors. Luckily for us, there are general rules that tell us when to water a cactus plant.

Water cactus plants only when the soil is at least 90% dry. You need to monitor the plant’s condition and the soil’s dryness to know when to water. Use a moisture probe or your fingers to determine the soil moisture levels. In general, they require very little water when compared to other houseplants.

Water your cacti in the morning so that there will be no excess moisture at night. Doing so will help prevent plant diseases.

How Often to Water Cactus

Unfortunately, when it comes to this desert plant, you cannot set a fixed watering schedule because, as mentioned above, many factors affect the plants’ watering needs. For instance, indoor cacti require less watering than outdoors because their growing conditions are different.

Another factor is the plant’s age. Younger cacti are usually more demanding and need water more often to support their growth. These plants also require more watering in spring and summer than in colder months since they are actively growing.

Generally, small cactus plants indoors will need watering every 10 days or more for optimal growth during spring and summer as soon as the soil has dried out completely. Increase the interval between watering schedules during the plant’s dormant period during winter (approximately every 4 to 6 weeks).

What Type of Water is Best for Cactus Plants?

The type of water is another crucial factor in growing a healthy plant. For an indoor cactus, the best options are rainwater and distilled water.

Unlike soft water, hard water, or tap water, rainwater contains the right amounts of minerals that a cactus plant needs. Other water types have lots of minerals that can build up in the soil and affect your plant’s health.

How to Water a Cactus Plant

You can use several methods to water succulents, but the best way is deep watering. During each watering, soak the soil thoroughly until water starts draining out the pot’s drainage holes.

You can also drip water slowly around the roots. Another method is placing the pot on a saucer filled with water, allowing the plant to take in moisture through the roots.

Regardless of the method you use, do not mist your cactus. They do not like humidity or water collecting on the modified leaves. Water at the base and avoid overhead watering to prevent plant disease formation.

As discussed above, a cactus plant’s water requirements depend on many external factors like temperature, light, soil mix, and more. You will get a better gauge of how much water your plants need if you pay attention to those factors.

What To Do Between Watering Cycles

Allow your cactus plant to dry out between watering cycles. Make sure that the soil is completely dried out before the next watering. You can use your fingers and manually feel the soil’s dryness. You can also use a water gauge to determine the moisture level, or simply pick up the pot to determine how heavy it is.

Watering Cactus Plants After Repotting

Repotting is one method that helps your cactus plants thrive. The practice allows extra space for growth and helps reduce mineral buildup in the soil.

When repotting cacti, you may wonder if you should water your cacti plant immediately after repotting.

The answer is no. The process of repotting damages a cactus plant’s root system. After the transfer, the root system is still fragile and needs some time to heal. So, it’s best to leave it for a couple of days until it recovers before watering it. Watering immediately after repotting may lead to root rot.

Overwatering and Underwatering Cactus Plants

Overwatering and underwatering are common issues encountered by beginner cactus hobbyists – especially overwatering. Most are not sure how much water to give their cactus plants. As a result, they are unknowingly underwatering or overwatering their poor houseplants.

Unfortunately, underwatering or overwatering leads to undesirable results and potentially to your plant’s demise. You can easily avoid this by watching out for signs of poor watering practices.

Signs of an Underwatered Cactus

Your cactus tells you that it needs more moisture through one or more of the following symptoms:

• Pale, rubbery, and deflated leaves
• Discoloration on the leaf and stems
• Withering leaves
• Drooping leaves
• Dryness in appearance and to the touch
• The lighter weight of the pot

While you may think that your cactus is dying, there’s actually an easy fix to help revive your plant’s vigor. When it starts showing signs of underwatering, simply water it thoroughly. Wait for a few days, and your plant will bounce back to its healthy state.

Signs of an Overwatered Cactus

As with underwatering, overwatering is something that you should avoid when taking care of cactus plants. It’s more severe than underwatering since the effects of excess moisture are often irreversible. Here are the signs of overwatering in cactus:

• Rotting or decaying plants
• Leaves and base are turning brown or black
• Plants appear overly plump

Overwatering results in waterlogging in the soil. This isn’t favorable for any cactus or succulent since it can lead to root rot, killing your plant.

Wrap Up

Proper watering is crucial in growing cacti as it helps promote growth, flowering, and fruiting. Although watering is a simple process, you need to make extra efforts to know when and how to hydrate your cactus houseplants. Familiarizing yourself with the factors affecting a plant’s watering needs will help you grow beautiful and healthy cactus plants in your home.