Cacti plants are widely known for their drought-resistant nature and good water storage properties. This is the primary reason why they are referred to as desert plants. Since most of them do well in arid and semi-arid areas, gardeners usually assume that these plants require direct exposure to bright and intense heat to thrive. But is that the case? We shall find out in a moment.
Does cactus need direct sunlight? Most cacti species don’t need exposure to direct sunlight to survive. Just like other succulents, cacti plants will do well when positioned in places with good light and not necessarily direct sunlight. If you are growing your plants indoors, position them on a south-facing window to help them access bright light. If you are growing these plants outdoors, choose a perfect location within your garden with partial shade to help protect them from intense sunlight.
Depending on their place of origin, some cacti species cannot tolerate full and direct sunlight. Such species tend to suffer from damage and sunburn if you don’t provide them with some form of protection from the intense heat. However, a few other species have developed a wide range of adaptations that help them handle direct and intense sunlight much better.
Read on to find out everything you need to know about exposing cacti plants to direct sunlight and how you can protect your precious little plants from potential damage.
Do Cacti Plants Need Exposure to Direct Sunlight?
Naturally, cacti plants tend to do better when they receive a lot of exposure to light, but they do need protection from intense heat and direct sunlight. Too much heat can cause severe damage to your plants.
Typically, prolonged exposure to direct sunlight can result in sunburn damage leading to permanent scarring or even death. To prevent this from happening, it is always good to slowly acclimatize your plants to the intense sunlight before full exposure.
Start by positioning them to partial shade and slowly introduce them to more and more sunlight until they are fully acclimatized to the sun and heat. You can start by exposing them to the morning sun, which is less intense and slowly works your way to the more intense afternoon sunlight.
You can also position your cacti under the shade of other tall plants before moving them away and exposing them to direct sunlight.
The primary target here is to increase sun exposure gradually to avoid shocking the plants and causing sunburn or permanent scarring.
Keep in mind that shade-loving cacti species such as Mistletoe Cactus and the Easter Cactus and newly propagated plants are more susceptible to sunburn and permanent scarring. However, grey, red, or blue cacti plants covered with a lot of spines tend to do well under direct sunlight.
Sun-hardy cacti-species that have been accustomed to growing indoors are also susceptible to sun damage and sunburn when moved outdoors abruptly. Therefore, it is always good to find ways of acclimatizing the plants to intense heat slowly before you position them under direct sunlight.
Newly propagated or young cacti plants won’t do well under direct sunlight. Give them some time to mature before you can start to position them under direct sunlight.
Since different parts of your outdoor spaces get hit by direct sun rays at different times of the day, it might take some trial and error to determine which location will suit your cacti plants best.
Some of them may respond well to the morning sun while others may respond well to the intense afternoon heat.
Monitor them carefully under different circumstances to see how they respond to the different heat intensities.
How Many Hours of Sunlight Do Cacti Plants Need?
Typically, most cacti species need at least four to six hours of sunlight to thrive. These plants love being in bright and sunny locations. Plants that don’t receive sufficient exposure to light may exhibit a wide range of signs.
Perhaps, the most common sign that your plants aren’t receiving adequate light is etiolation/elongation. This is a process whereby plants stretch to seek more light. While it may seem like an excellent self-adaptation mechanism, etiolation produces weak stems and may result in poor growth.
Cacti plants that do not receive sufficient exposure to light may also become pale or revert to their original green color. On the contrary, plants that receive adequate exposure to light demonstrate their true beauty by showcasing a wide range of vibrant colors.
Can Cacti Plants Receive Too Much Sun?
The simple answer to this question is “yes.” Too much sunlight is what causes sunburn and sun damage in cacti plants and other succulents. The unfortunate thing is that sunburn may happen pretty quickly during a heatwave or when the temperatures soar so high. Sometimes, the process can also occur gradually.
The first sign of sunburn is the appearance of brown/yellow spots on the surface of your plant. Fortunately, if you realize signs of sun stress early, the effects can easily be remedied to avoid further damage to your plants.
Simply relocate your plants to a shady area or position them next to other taller plants for protection from excessive sunlight. If you don’t do anything even after realizing signs of sun stress, some cacti plants will fry to a crisp and eventually die.
Some species may toughen up, adapt to the intense heat and survive the heatwave. Don’t take any chances; make sure you provide your plants with sufficient protection when temperatures start to soar.
Can Cacti Plants Survive without Sunlight?
So, the next question you must be asking yourself is whether your cacti plants can survive in low light conditions. Well, the truth is that cacti plants, just like any other plant, need sunlight to survive. The light energy absorbed is used to trigger chemical reactions that help the plant produce food and energy.
However, cacti plants can still survive in low light conditions for some time. After a few days of insufficient exposure to light, your plants will start to show signs of stress such as etiolation and stunted growth. They will also lose their beautiful vibrant colors and appear pale.
When given too much water and little exposure to light, cacti plants may succumb to root rot. If you don’t take appropriate measures to correct the situation, the plant will start to rot from the roots up and eventually die. In fact, when root rot starts to set in, it can be quite difficult to save your plant from death.
How Can You Keep Your Cacti Plants Alive during Prolonged Heatwaves?
With the effect of climate change, weather extremes are quite common in different parts of the world. Some regions experience extreme heatwaves that can easily cause harm to succulents. Heatwaves, especially during summer, can be challenging to deal with, given that they can last for days or even weeks.
You risk losing your plants if you leave them unattended during this period. So, what can you do to protect your cactus from the stress and potential damage? Here are some of the things you can do to protect your plants during this period.
Provide your plants with shade
One of the best things you can do during such a period is to prepare ahead of time. If you anticipate a heatwave in the coming days, find good shelter for your young, smaller, and fragile cacti plants.
Move them to shadier spots of your garden and if possible, take them indoors. The taller, mature, and bigger plants that are accustomed to the outdoor heat may be fine, but you should still monitor them closely.
If you have planted your plants in the ground or in beds, then consider covering them with a shade cloth since you cannot move them.
This might not be the right time to repot your plants. Remember the fact that repotting even a mature and well-established cactus plant introduces a lot of stress to it. Therefore, doing it at a time when the temperatures are too high will only make things worse. Wait until the heatwave has subsided and temperatures dropped back to normal before you start to repot your plants.
Do not fertilize
Fertilizing your cacti plants can help them thrive and grow fast. But, you need to know the right time and season to fertilize your plants.
Preferably, you should only fertilize your plants during spring when they are actively growing. During a period of a heatwave, your plant’s main focus is to survive and not grow. So introducing extra nutrients to the plant during this time can only cause more damage than good.
The Bottom Line
Cacti plants tend to thrive when located in areas that receive plenty of bright light. However, this doesn’t mean exposing them to direct sunlight. Some cacti plants are prone to sunburns and sun damage when positioned under direct sunlight.
If you live in the northern hemisphere and grow your plants indoors, consider placing them on south-facing windows which are a good position that provides excellent access to sunlight. The optimum amount of sunlight required largely depends on the cacti species that you are growing. For instance, while Rhipsalis cactus does well in shaded areas, Echeveria will only blossom when positioned in bright spots.