When you hear about cactus, you think about the desert. Not all cacti are found in the arid areas, some even grow in tropical rainforests. However, for the desert cacti, they have adapted to the harsh climate and have found a way to survive. Their widespread roots collect water from a large area, so even when it dries up, they still survive.
Even as you decide to purchase a cactus, you need to know how to care for it. One significant aspect of this is watering the cactus. When and how should you water the plant? Below are some golden rules for watering your cactus.
1. Knowing how often you should water your cactus
Every cactus is different, and it is up to you to learn how to grow it by observing any change when you either water, repot, fertilize, or propagate. Knowing how often you should water your cactus is essential as it helps the plant thrive.
One fantastic thing about these plants is that they are quite tolerant of water neglect. However, too much neglect will see their leaves or stems turning pale or yellow.
Here are some tips to help you know how often you should water your cactus:
During the growing season (March to September), cacti need regular fertilizing and watering. Water them at least once a week to avoid them drying out. When dormant, only water if they are completely dry.
Before the next watering period, make sure the topsoil is completely dry. You can get a water gauge to help you know the moisture level. Alternatively, you can get a stick and stick it into the soil, if it comes back dry, that means the plant needs water.
Watch out for signs for underwatered or overwatered cactus. An underwatered cactus will look pale while an overwatered one will look abnormally plump, which eventually leads to root rot.
2. Consider the cactus size
Small younger cactus will often need more water since their growth rate is high. This means you’ll need to water them frequently compared to older cacti.
The large cacti have a small surface area to volume ratio, which decreases the evaporation of water from the plant’s surface. However, you will still need to water the cactus.
3. The type of soil determines how much water the plant needs
When you initially purchase your plant, ensure you also buy an excellent potting mix. Soil is a crucial aspect of growing cactus as it determines if it retains or drains the water.
The soil needs to be able to drain so that when the cactus has had enough water, it can quickly drain the excess water through the drainage holes on the pot.
To check if the subsoil is draining correctly, you can remove the existing topsoil to confirm.
The cactus will need a sandy, pebbly, and porous potting mix which drains well and provides proper aeration. It will also have organic matter whose work mainly is to provide moisture to the cacti roots and at the same time with the ability to dry quickly.
Alternatively, you can make your own potting mix to ensure once you water, it drains effectively. The steps below should guide you in making a potting mix which may be cheaper than buying one:
Step 1: Combine equal portions of ground fir bark and peat moss or coconut coir in a bucket to form a potting mix.
Step 2: Mix two portions of the potting mix with one portion of the coarse builder’s sand. This is most notably for the holiday cactus and the tropical species. This is because these particular types retain more moisture than desert cacti. For the sand, you can substitute with pumice, perlite, or vermiculite.
Step 3: Use equal portions of the sand/pumice/vermiculite/perlite and mix with the potting mix for the desert cacti because they don’t do well in water retention soil.
Step 4: Mix everything and make sure there are no soil lumps until the soil blends well.
Step 5: The soil should be ready for your cactus; make sure you water thoroughly before planting the cactus.
4. How seasons affect the watering schedule
Seasons all year affect how cactus grow. How you water them during these seasons also determines if they thrive or not. As the weather changes, the watering needs also change.
Below is a guide on how you water them in different seasons.
During winter, cactus will need just occasional watering because most of them are dormant during this period. They stop growing when the temperatures drop. The most appropriate watering frequency would be once a month. The cold helps the soil maintain some moisture hence no need for watering often.
The spring showers are what will impact your watering pattern. They will act as a guide towards watering, but it should ideally be weekly since the plants are ‘waking up’ from dormancy and will need the extra water to thrive.
Due to the hot temperatures, the soil is bound to dry quickly. The location also contributes highly to how often you water because some areas are extremely hot while others are not. Physically check the soil to feel the dryness or wetness and see if you need to hydrate your plant. Ideally, it would be twice or thrice a week.
If it’s warmer than 40 degrees Fahrenheit, at least water once weekly.
5. Be mindful of what containers you use
Containers range from plastic to clay pots. The type of container you use to plant your cactus will determine if you water more or less often.
Small and shallow containers will eventually evaporate water quicker than wider ones. Some containers are less porous than others, and it’s upon you to know if what you use drains water quickly or not.
Types of pots and how often you should water the cactus depending on the type:
The ceramic pots are from hardened clay. For the unglazed ones, they are quite porous and allow water to drain through the sides. The clay absorbs moisture from the potting soil, especially if the cactus prefers dry soils. Unlike the unglazed pots, the glazed ones don’t absorb moisture; they are not porous and don’t dry out fast. Regularly check the soil for moisture so that it gives you an idea of when you should water the cactus.
Their advantage is they are perfect for indoors and will shield the plant from temperature changes.
These pots are heavy but will crack if they are left out in freezing weather. They can also be quite costly.
Terracotta pots are also made from clay just like the ceramic ones and are unglazed. They come in earthy colors and all kinds of shapes. They are porous and often drain water quickly. They allow water to pass through the walls easily.
They are light, unlike ceramic pots. What’s even attractive about them is that they are affordable, which makes them more ideal for growing your cactus.
With these pots, you need to keep continually checking if there is still water.
They are however susceptible to cracking when exposed to extreme cold.
Plastic containers are quite common when growing plants. They are light and can be crafted to look like terracotta or ceramic pots. Due to technological changes, plastic is no longer the annoying plain type but instead comes in a variety of designs that are appealing and durable.
One downside, however, is that they don’t drain quickly. Therefore, you need to water your cactus less often to prevent its roots from rotting.
For these particular containers, they are made from woven resin and fiber. They have a resemblance with clay pots and can be molded in different shapes and sizes. They are quite durable and can withstand even the harshest of weather conditions.
Since these containers don’t allow water to drain quickly, some of them come with drainage holes. However, for cacti species that don’t love wet soil such as the desert cacti, they are not ideal.
Water the cactus when the soil is completely dry to reduce the chances of root rot.
Metal containers are available in different shapes and sizes. They are durable and are resistant to extreme cold weather conditions. They are prone to rust but can be coated to avoid rust.
During the hot season, they absorb heat quite fast and can burn the cactus, especially if left under direct sunlight. They don’t drain water as most don’t come in drilled drainage holes.
Even as they come in attractive shapes, they are not quite ideal for cactus. In the case you use them, make sure you only water when it’s necessary to avoid bacterial infections.
For such containers without drainage holes, you can use a spray bottle or syringe to water the plant so that you control the amount of water that gets into the pot. You need the water to get to the roots and not flood the whole soil area.
In case you overwater, using a dry towel, dab the water to remove the excess water.
Wood is also another option of growing your cactus. Wood is safe for outdoors as it doe not crack. These types of containers hold moisture in and are slow to dry out completely. Roots can quickly rot in these containers, which call for you to use plastic lining.
Water cactus planted here sparingly as you observe the water retention rate.
6. Keep the location of the cactus in mind when watering
Depending on where you grow your cactus, the watering schedules are bound to be different. You either keep your plant indoors or outdoors.
How to water indoor cacti?
Cactus hold moisture in their leaves and stems. The biggest mistake that could happen is wrongly watering them. As mentioned, overwatering them could cause root rots and eventually kill the plants. Underwatering them will also dry out their roots and eventually not grow.
How much water you use depends on the season. The growing season is when the cacti record the highest growth, which means their water requirement is slightly higher. Water them until it begins to drain out through the drainage holes. Draining the water is essential as it prevents any dissolved salt from staying in the soil.
For the majority of the indoor potted cacti, watering once every ten to fourteen days should be adequate during the growing season.
During the dormant season, the plants need less water. Before watering, a golden rule is to check the soil for any moisture. Unlike other plants, cacti require water when the soil is completely dry because they store the ‘water’ in their leaves and stems.
Paying attention to how your cactus looks should also guide you on whether it needs water or not. During the dormant period, water only once every three to four weeks. In the case the cactus starts looking pale, you can increase the watering frequency. If you are not sure about the watering pattern, you’d slightly underwater than overwater as the cacti can bounce back unlike where there’s excess water which causes the roots to rot.
During winter, we are bound to use heaters to maintain the home’s warmth. The heaters can be extra drying, which affects the cacti. As a remedy, you can place a water tray near your cactus. The water will evaporate and humidify the air which works for your plant.
Another option of correcting humidity in the room is the use of humidifiers. They help keep the room moist. Also, a dehumidifier works when you want to remove excess moisture in the air as well.
How to water outdoor cacti?
Outdoor cacti are exposed to different growing conditions with the indoor ones. As such, their watering schedules are slightly different. Just like the indoor ones, you need to confirm the soil is dry before watering.
To check the moisture level, moisture meters are a great option. They help you not over/underwater the cactus. The market is flooded with gadgets, with each having different features. Some are battery-powered while others are not. Others even show the soil pH.
To read the moisture level, press the probe ¾ into the soil and be on the lookout not to damage the roots. After a few minutes, remove the probe from the soil and view the results after a few minutes. Whatever you choose, they’ll surely help you out before you figure out gradually how to tell if your cactus needs water.
Water once every seven to ten days during the growing season because that’s when the water requirement is high. To know if you’ve watered well, the excess water will sip out through the draining holes.
Just as the indoor cacti, during the inactive season, you should water once about every three to four weeks. However, note that you don’t have to wait until you feel the plant is stiff-dry. After some time, you’ll get accustomed to the routine, and you’ll tell when your cactus needs water.
The best time to water outdoor plants is in the mornings. It will give the cacti plenty of time for the water to reach the roots and keep it hydrated to deal with the afternoon heat. This routine also prevents the plant from sunburns.
7. Using the right type of water
The type of water you use also determines if you grow a healthy cactus or not.
Soft water is water that’s treated with potassium or sodium to remove minerals such as magnesium and calcium. If soft water contains high ratios of sodium, it can destroy your cacti because it causes buildup in the soil. It eventually over time dehydrates the plants and interferes with the absorption of water for the plant.
Hard water contains calcium and magnesium. It is prone to leave marks on the plant and buildup on the soil which destroys your cacti. Repotting can help in getting rid of the buildup. It’s recommended that you repot after every one to four years.
Rainwater is the preferred type to water your cactus as it contains the right amounts of minerals. Since rainwater is not available year-round, you can store the water for later use on the plant.
Also, you can dilute the tap water with the rainwater to reduces the buildup of salts in the soil. This temporarily works, which is why you need to repot to minimize the chances.
Removing mineral deposits on your cactus
When you notice there is buildup on your plant, whether, on the leaves or stems, you can find a solution to removing them.
You need one tablespoon of vinegar and some distilled water or rainwater. Mix the vinegar with the distilled water in a container. Using a cotton ball, wipe off any visible stains or mineral buildup. Use the same solution also to wipe off your containers or pots.
8. Know the particular species
When purchasing your cactus, it’s essential that you know the specific species. Knowing your cactus’s origin will help you mimic the previous conditions.
Different cacti have different water requirements. There are those from tropical rainforests, while others are found in arid areas. Knowing this will help have a more defined watering pattern. It will also help you determine what container you’ll need.
Cacti from arid areas don’t need excess water. They need a pot that drains water fast unlike those from tropical rainforests which don’t mind some bit of water.
For example, the Prickly Pear is from arid areas and will require a pot that drains water fast for better growth. The Orchid Cactus grows in rainforests and wouldn’t mind a bit more water than the Prickly Pear.
9. Choose your pot size wisely
Choosing your container size determines whether water drains faster or not. The ideal choice is going for smaller containers because it is almost a crime for a cactus to stay soaked in water for an extended period. Long periods will lead to bacterial infections caused by the rotting of the roots. You will need to water small pots once every week or less depending on the plant’s needs and how fast the soil dries.
Large pots mean water will take more time to evaporate. This means you will water them less often. Cactus in large containers can be watered every 4-6 weeks. However, the danger of this is the fact that soil will get soaked in the water, which in turn wets the roots that will eventually rot.
Just get a pot that’s the right size for your cactus. As you repot, since the plant will have grown, you can move a size up your original container.
10. If growing cactus, consider the lighting
Usually, direct sunlight will make the rate of water evaporation and drying of soil higher. This will need you to water the cactus more often. If you grow your cactus indoors, the side it faces determines how often you water the plant. If it’s placed at a window facing the south, you will need to water it regularly. However, for a north-facing window, the water requirements will be less frequent.
11. Get to know how to check if a cactus is overwatered or underwatered
As mentioned, overwatering and underwatering can be quite detrimental to the cactus’s health. Knowing how to water just the right amount helps your plant grow in stable conditions.
How do you tell if your cactus is underwatered?
It is quite easy to spot a deprived cactus. Some common signs are:
- Cacti will often discolor when they have insufficient water. They usually turn pale than their natural color or become brown.
- They usually wither because they have used up all the water in their reserves (leaves and stems).
- They become dry as they get deprived of moisture due to using up all the water they had stored.
- The plant will start wilting and their leaves drooping.
- The weight of the pot also becomes lighter.
As alarming as it may seem, you shouldn’t panic too much as it is easier for a cactus to regain its normal state when underwatered than when it’s overwatered.
When your cactus show signs of underwatering, water it thoroughly. It should bounce back to healthy leaves and stems in a few days.
How do you tell an overwatered cactus?
Overwatering is quite severe compared to underwatering because the effects may be irreversible. If the cactus looks overly mushy, that’s a clear indication of overwatering. The following signs show an overwatered plant:
- The cactus will appear to rot or decay.
- The leaves and stems will start changing color by turning brown or black.
- The base will also start turning black.
Cactus have sensitive roots that quickly rot if neglected. Once they rot, they can no longer absorb water and other nutrients to transport them to other parts of the plant. This is what causes them to change color and wilt.
Root rot isn’t immediately discoverable. Your cactus may look healthy from the outside, but the roots are slowly rotting, and the plant eventually gives way.
How to deal with root rot?
Sometimes, given the symptoms discussed above, you may suspect your cactus roots are rotting. You will need to remove the cactus from its pot and inspect the roots. The roots should be white. If they are black or brown, they have root rot.
If the plant has some sections of root rot, the plant is not totally destroyed and can be saved. You can use shears to cut the contaminated parts. Repot the plant by using some other potting mix so that it can regain its health.
Don’t forget to thoroughly wash the shears after cutting the infected roots to avoid further contamination of other plants. Discard the cut roots and previous potting mix.
How to water your cactus?
- Deep watering is a method where you soak the container/pot until water starts draining out the drainage holes.
- You can use a saucer of water to take in moisture through the roots. Once the water saturates the soil almost halfway up the soil, you can remove the plant from the saucer.
- Using a garden hose to drip water slowly for a few hours around the roots.
Knowing your cactus species will help determine what method will work for your plant. Sometimes, even the water schedule may be a bit tricky as the cactus may adapt to new conditions.
Proper watering of cactus during spring and summer is vital as it helps in cell production, blooming, and fruiting. You need to take your time and study your plant to know its water needs. As much as the rules above are straight forward, make sure when you are purchasing your plant, you get some background information on its origin and living conditions so that when you take it home, you can try to replicate those conditions.