Among the diverse and attractive world of plants, a few have the power to fascinate our imagination.
Within these extraordinary marvels, the presence of cacti stands tall.
With their distinctive shape and unique features, these plants have become a popular addition to homes and gardens. That’s why many gardeners and plant enthusiasts have made their unique cacti collection.
But there are still some beginners out there who are just starting, and a question that’s constantly asked is: Do cactus need direct sunlight?
This blog post will go through a detailed guide about cacti and their light requirements.
So, without wasting further time, let’s begin!
- Do Cactus Need Direct Sunlight?
- How Much Sunlight Do Cactus Need?
- How Do You Know If Your Cactus Is Getting Too Much Sunlight?
- Where Should You Keep Your Cacti Plants?
- Will the Light Requirements Change During Dormancy?
- How Long Can Cactus Go Without Sunlight?
- How Do You Know That Your Cactus Needs More Sunlight?
- Can Cactus Survive Without Sunlight?
- How to Know If Your Cactus Is Full Sun or Shade-Tolerant Cacti?
Do Cactus Need Direct Sunlight?
Succulents are trendy houseplants because they are easy to handle.
When discussing cacti, it is important to note that these desert plants are drought-resistant and have water storage properties like desert animals (camels).
Due to this property, they grow well in arid or semi-arid environments; that’s why most of us think all cacti need direct exposure to sunlight to grow well.
But is this statement true? Let’s find out!
Most cacti species do not need direct sunlight; they can do better in indirect light and require little exposure to direct sun.
Some cacti species cannot tolerate direct sunlight. These species tend to get damaged and sunburned if you don’t protect them from the harsh rays of direct sun.
However, some species need direct sunlight to thrive best.
I understand that all plants need sunlight to grow and survive because it is necessary for photosynthesis, but the amount of light required may vary, as in the case of cacti.
Regarding photosynthesis, cacti are unique because most of their chemical reactions occur in low sunlight, and when the sun shines at its peak, they can complete the process.
So, if you’re eager to understand the ins and outs of exposing cactus plants to direct sunlight and discover practical methods to shield them from harm, just read on!
How Much Sunlight Do Cactus Need?
Do cacti always need to be exposed to direct sunlight?
Well! the answer is not simple!
As I told you earlier, cactus plants have many varieties, and their need for sunlight differs greatly.
Mostly cacti plants need 4–6 hours of direct sunlight exposure to survive best.
But some succulent cacti can grow well in low light, so we call them low-light succulents. They only need 3–4 hours of sunlight to live happily.
Some cacti live best in direct sunlight exposure of 10–12 hours; these are full sun varieties.
It would be best to be careful because excess sunlight can be destructive.
So, does it mean all cacti need hours of direct sunlight?
Growgardener’s NOTE: Most people think cacti grow in deserts in dry environments where they survive under direct sunlight, but because cactus plants grow behind rocks or bushes, they actually receive indirect sunlight, under which they thrive!
This shade protects them from sun damage.
So, what do you understand from this answer?
Yes! Most cacti do not grow well under direct sunlight exposure, even if they don’t get sunburned.
But how do you know that your cactus plant is getting excess sunlight?
Here is an effortless way!
How Do You Know If Your Cactus Is Getting Too Much Sunlight?
Different cactus varieties have different tolerance to direct sun. Some like to bathe in bright sunlight, while some prefer slight shade. I have provided the details about some common cactus varieties further in the article, so you must look for the one you have at home.
Studying your cactus plant type before planting them in your garden is better.
Prolonged exposure to sunlight can cause sunburn to your cactus plant.
The most common signs of sunburn are:
- Brownish discoloration
- Yellow marks on leaves
- Scarring of the plant
If you notice similar signs in your cactus, gradually move it to a lower light area for a few days, and don’t take it under the direct sun until it is fully healed.
To save your plant from getting sunburned, it is advisable to understand the optimal placement—where should you keep your cacti?
Where Should You Keep Your Cacti Plants?
As we know, cacti don’t need prolonged daylight exposure because of their unique photosynthesis process, so placing them under partial shade is better.
The best spot is where your cacti get both sunlight and shade, and this would be a nice sunny south-facing window.
For even plant growth, you should keep rotating your cactus every 2–3 weeks so that all sides of the plant receive adequate light exposure.
Will the Light Requirements Change During Dormancy?
Dormancy is when a plant’s metabolism slows down and conserves energy, but even so, it still needs sunlight.
Cactus plants are cold hardy.
They can tolerate cold temperatures, and when the weather changes, they return to normal.
A couple of cold hardy cactus from the Opuntiagenus are:
The one thing to remember during dormancy is that plants still need water and sunlight, but the consumption rate is low.
So, 4 hours of sunlight would be enough for cactus plants during dormancy—the days are shorter in freezing weather, so it would be okay to maximize sun exposure.
But still, on a sunny day, save your cactus from the scorching heat.
How Long Can Cactus Go Without Sunlight?
Cacti can survive with little to no sunlight, but their growth will be stunted and dull.
No sunlight means no photosynthesis, and it can affect their growth.
Cacti can live a few days without sunlight.
But at some point, your plant will need sunlight to fulfill its need; otherwise, it results in growth defects and etiolation.
“Etiolation is when plants grow without light, with weak stems and pale color.”
It could be an alarming sign that your cacti are dying.
But is there any way to treat cacti when they become etiolated?
Fortunately, the answer is Yes!
You must give your plant back what you have taken away—the sunlight. Yes! Expose your cactus plant to sufficient sunlight, and your plant will revive soon. Place it near a window, but don’t go above and beyond.
Gradually move your plant closer to the sun to give them the right amount of sunlight.
Etiolation does not go away at once; it will take time, and you will have a nice wide cactus growing safe and sound again!
How Do You Know That Your Cactus Needs More Sunlight?
You should know how much sun exposure your cactus needs. When your cactus is not getting sunlight, it seems weak and unhealthy.
These are the signs you can notice in your cactus deprived of sunlight:
- Their growing pattern slows down, and it is noticeable.
- Your cactus’ spine will start to change color.
- You can also see some black or brown spots on your cactus.
If you see any of these signs, it is time to worry about your plant.
Please take a quick move and place them into direct sunlight again, but your plant must get shade for some hours in a day, so they don’t get sunburned.
Can Cactus Survive Without Sunlight?
The answer is a big NO!
Cactus plants have a specific photosynthesis process called Crassulacean Acid Metabolism and CAM photosynthesis.
CAM photosynthesis occurs in desert plants.
The reason behind it is that it is very harmful for desert plants to open their stomata in such a hot and arid environment. Therefore, they open them at night for gaseous exchange.
With the help of CAM photosynthesis, cacti can store carbon dioxide for prolonged periods in their system—once sunlight is available, they will do their required chemical reaction.
This adaptive feature of cacti is short-term, and it doesn’t prove that they do not need direct sunlight.
How to Know If Your Cactus Is Full Sun or Shade-Tolerant Cacti?
While discussing the light requirements of the cacti, it is essential to understand whether your cacti are full sun or shade-tolerant cacti.
Determining whether your cactus is suited for full sun or slight shade can be done simply by observing its characteristics and growth pattern.
Some cacti that require full sun to thrive include:
- Prickly pear: This cactus is widely known as the most drought-tolerant variety. It has shallow roots which can capture water and store it. If you plan to grow them indoors, plant them in pots.
- Echinocereus: These cacti look like hedgehogs. These varieties of cactus are also considered edibles. Its body is softer than others, covered with spikes. It is ideal for sunny areas.
- Saguaro cactus: These are columnar-shaped giant cactus that can grow about 50 feet or more, but they grow best in deserts, and they have a slow growth rate, so they need as much sunlight as possible.
- Parry’s agave: It has greyish-blue-green leaves and is a highly drought-resistant cactus. It could be an excellent choice to grow as your indoor plant.
On the other hand, some varieties survive only in shades, like:
- Schlumbergera, aka Christmas cactus: Schlumbergera grows on trees or rocks. It is a popular houseplant that blooms in winter in beautiful shades of red and pink.
- Rebutia: It looks like a crown and is also known as the Crown cactus. It owns the royal horticulture society award. Rebutia usually grows in clusters on mountains and does best in shady areas.
- Epiphyllum: Also known as Orchid cactus, Epiphyllum usually grows in shaded regions on tree branches. It has flat, leaf-like stems, allowing it to absorb sunlight better.
- Selenicereus: It is also called Night-blooming Cereus. It grows on trees and rocks in climbing stem patterns. This fragrant flower cactus is adapted to low light.
That’s all about cacti in today’s article.
Now it’s time to move towards the conclusion.
So, do cactus need direct sunlight?
Well! the answer is totally based on the variety of cactus you want to grow. It is because some species like to grow in direct sunlight while others grow best in partial shade, so you must choose accordingly.
Make sure to protect your plant from direct sunlight, but make sure to provide sufficient light as well. Many people don’t provide their plants with adequate light just because they fear they will get sunburned.
Always remember that insufficient light wouldn’t allow your plant to grow well.
The best thing is to understand whether your cacti are full sun or shade tolerant.
I hope this post helps you a lot!
If you have any queries regarding the cactus plants, please mention them in the comment section below.