The answer to whether cacti can die or survive without sunlight is either a yes or no. Some Cacti species can survive for short periods without sunlight. However, others need full sun and will not survive if you keep them in the dark place.
Because cacti plants have their natural habitats in the desert, they’re used to the harsh sunlight and will not survive if you deny them the light. Many species need exposure to lots of sunlight to grow well and even produce flowers. Some require at least four hours of direct sunlight to flourish. Others are known to need very low amounts of light to survive, but they still won’t survive with zero light. Not giving your cacti enough sunlight exposes them to infections and prevents them from blooming.
If you’re wondering about the light requirements of cacti and how you should expose various species to sunlight, this article is for you. Here is a comprehensive guide on cactus and its light requirements.
How Much Light do Cactus Need?
The light that your cactus needs to thrive is measured in duration since you cannot quantify light. Instead of asking how much light, you should ask the duration of the light that your plant needs. Cacti need around 10-14 hours of sunlight each day. Well, this doesn’t include the cacti that love the shade because those will burn if exposed to light for that period.
Many cacti plants have devised techniques to help them get the amount of light they need. Others have taken distinct shapes that help them minimize their exposure to the sun. Some types elongate their branches and tend to grow towards the direction of the sun.
Other cacti feature highly modified leaves that help them minimize evaporation as a result of sun exposure. Make sure such plants only get four to five hours of sunlight every day.
How Do You Know the Amount of Sunlight that Your Cacti Need?
Since you’re going to grow different species of cacti, it will be hard to know which one needs what amount of light. Well, most species love light exposure and will do pretty well under intense heat. But too much of it can cause damage to even the hardiest plant out there. Cacti also suffer from sunburn damage which can cause scars or even kill them.
Don’t subject your precious plants to full sun exposure right away. The best cause of action is positioning your cactus under partial shade and slowly exposing them to more sun until they get used to it. Consider getting them out in the morning sun, which is less intense, then gradually introduce them to the hotter afternoon sunlight.
You can also consider placing your young cacti under the shade of other plants before exposing them to direct sunlight. Gradual exposure is vital to avoid sunburn and permanent scarring due to the intense heat.
Cactus plants that love shade are more susceptible to sunburn and scaring. Such cacti include Easter cactus and Mistletoe Cactus. However, cacti plants come in blue, grey, and red plants highly covered with spines love direct sunlight exposure.
Cacti that are used to growing indoors will also suffer sunburn and damage when moved outdoors, where they’ll suddenly get sunlight exposure. Whatever the plant you plan to move to more light, make sure you do it gradually, so you don’t stress your precious plants.
Don’t expose newly propagated cacti to the sun as they can also suffer damage. Allow them to mature and become strong enough to deal with the intense heat. Monitor your plants carefully and find out which one will do well under direct sun and which one needs shade.
Do Cactus Need Bright and Direct Light?
Some cacti need bright and direct light, while others don’t. Others prefer bright but indirect light. This means you shouldn’t expose them to full sun. Some hate direct light and can kill them if exposed.
Rhipsalis, which falls under epiphytic cacti, cannot survive under bright and direct sunlight. They prefer shade and will do well under other trees or indoors. Other species need bright light but can also do well with the part sun. Good examples of such include barrel-shaped cacti, chin cacti, and Mammillaria cactus genus.
Those cactus species prefer bright and direct sunlight but sometimes need to go without too much light. If you treat them for infections or repotting, make sure you shade them from direct sunlight. Others also need time to transition for winter hence bright light will not do them any good.
Should You Give Your Cacti Artificial Light or Sunlight?
When it comes to cactus light requirements, both sunlight and artificial light do great work. But there are times when sunlight will do better than artificial light and vice versa. Let’s see how the two sources of light work.
Cactus Sunlight Needs
Natural light is usually the easiest to give you cactus plants because it’s easily available. You don’t have to do anything to control this light apart from just placing your cactus on the windowsill. Your cactus will know how to harness this energy and use it for various chemical reactions.
Most cactus plants were naturally made to benefit from sunlight, and they’ll appreciate it if you generously expose them to it. The plants have different adaptations that allow them to absorb only the light they need and protect themselves from excess heat. Exposing such plants to direct sunlight will not hurt them because they know how to adapt.
Maximizing Sunlight for Indoor Cacti
There are plenty of indoor cacti that still need natural light to survive. You should put such plants on windowsills so they can harness the sunlight that they need. The best way to ensure your cactus receives maximum sunlight; position them on the south-facing windowsill. This is where the sun heats most, and your cactus will receive maximum hours of sunlight.
But if you want your cacti to receive the strongest sunlight, which doesn’t last too long, place them on the east-facing windows. This is where you’ll get the strong morning sun which weakens as the day progresses. If your sunlight prefers partial shade, the north and west-facing window sills will do them justice.
Artificial Lights for Cactus
When there is no sunlight getting to your cactus, you’ll need artificial light to keep it going. This light is also important for the plants that can’t access the space on the windowsill. If you live in places that experience strong winter, you might want to transfer your plants indoors, and that means offering them artificial light.
When propagating your cactus, they’ll also need artificial light. Direct sunlight from the sun can be too hot for them. They need low-intensity sunlight.
Unlike sunlight, artificial lights are not free of charge, and you must invest in them. Make sure you find the right bulb for your plants and pay for electricity bills. Well, you should not panic because the bulbs don’t consume too much energy and the costs are generally low.
When choosing your bulbs, don’t go for those that get too hot or emit very little light. Usually, fluorescent bulbs or LED grow lights will do you good. Avoid incandescent bulbs or mercury vapor. 75w of grow lights is enough for an area of 5-10 square feet of growing area. Fluorescent bulbs cover a wider area.
Protecting Your Cactus from Heatwaves
Cactus species react differently to weather changes, and excess heat might damage others while some may survive. Either way, you need to ensure your cacti don’t suffer the excess heat, especially if you stay in areas that receive extreme heatwaves. Heatwaves mostly happen in summer, last many weeks, and can kill plants. You need to tend to your plants in several ways to avoid this. Here’s how to do it.
Give Your Plants Some Shade
If you think that your region will suffer heatwaves in the coming weeks, you need to prepare for it. You need to find some shelter for your young and fragile plants that might not tolerate the extreme weather.
If you have outdoor cactus, find them the shadier spots in the garden. For those species that do well indoors, take them inside to avoid heat. You might not be able to move the tall and mature cacti, but don’t forget to check on them often. Buy shade clothes for those cactus plants in the bed.
This will not be the best time to repot your plants because the heat will burn them right away. Even mature plants will undergo stress when you repot, and if you add intense heat to that, they won’t survive. Wait for the heatwave to subside, and the temperatures dropped before you can repot.
While fertilizers are perfect for the growth of plants, not all the time is fertilization time. The best way to fertilize in spring, when many of them will be growing actively. During a heatwave, your plants will be merely struggling to survive and will not grow. If you introduce new nutrients, you’ll only cause more damage than even that of a heatwave.
Cacti plants love light and will do well in areas that receive direct sunlight. Others don’t need direct light but will still need some form of light to survive. Denying your precious plants the much-needed light will only mean destroying them.
Direct sunlight or heatwave is likely to cause sunburns or even kill your plants. So, whether you choose to give your plants sunlight or artificial light, make sure you do it carefully. Too much or too little light both cause damage to cactus plants.