How Much Sunlight Do Cactus Need?

It’s no secret that your cactus can do without water and sunlight for extended periods. However, you don’t want to deprive it too much as it may lead to its roots rotting!

Are you wondering how much sunlight your cactus needs on average and whether or not you should expose it to direct sunlight?

You will find all the answers in this blog, along with some other questions you may have regarding sufficient light exposure and the placement of your cactus to ensure optimal growth.

So, keep reading!

Does Your Cactus Need Direct Sunlight?

If you are wondering whether you need to place the cactus in an area that receives direct sunlight, the simple answer is: no, you don’t because cacti don’t require direct exposure to sunlight.

Contrary to popular belief, a cactus thrives in areas with indirect sunlight or artificial light.

Even though a cactus does not require direct sunlight, you still need to take care of the amount of light it is getting.

Like all plants, over-exposure or under-exposure to sunlight can create growth problems for cacti.

You must also ensure that your cactus is protected from intense heat, as direct exposure can result in sunburn or cause the plant to dry out and eventually die.

The right amount of sunlight will ensure that your cactus flourishes over time!

How Much Sunlight Does Your Cactus Need?

Cacti plants are all about adapting and surviving in the toughest of conditions. Most cacti thrive in well-drained soils with plenty of indirect sunlight, warmth, and little moisture.

The same conditions are typical of desserts.

To answer your question, ‘how much sunlight does a cactus need?’, a cactus requires a minimum of 4 hours of light exposure and a maximum of 12 hours per day to grow and thrive. 

Remember that cactus plants are not shade-loving and do well in bright spots.

However, exposure to over 14 hours of light per day can harm the cactus; they are not immune to the harm caused by extended hours of direct sunlight exposure.

When considering how much light your cactus requires, it is important to consider whether your cactus falls under the category of desert cacti or tropical cacti since both these species have different requirements for light.

Tropical plants and succulents do best when they receive light gradually, whereas dessert cacti like to receive direct sunlight in the morning or evening.

Have you ever wondered why cacti have spines? Their distinct shapes minimize the amount of sunlight they absorb since leaves absorb much more direct sunlight than spines.

As a general rule of thumb, all indoor cacti require about 4 hours of bright direct sunlight.

You can test the amount of light your cactus is getting by taking a plane of white paper and holding your hand over it.

If you see a defined shadow, it is an indication that the light is bright enough.

Signs That Your Cactus is Getting Too Much or Insufficient Sunlight

Here are some signs of over or under exposure to sunlight that you should keep in mind!

Too Much Sunlight

Keep an eye out for the following signs that indicate that your cactus is receiving more light than it should:

  • Sunburns, scars, and scorch marks on leaves are the most common signs of over-exposure to light. If your cactus shows similar signs, you should immediately move it to an area with lower light intensity.
  • If your cactus gets over 14 hours of light in a day, it may become distressed, and you will notice discoloration, yellowing, or its stems turning orange.
  • Overexposure to light also disrupts the Crassulacean Acid Metabolism or CAM of your cactus plants –a carbon uptake system that gives cactus plants the power to reduce moisture levels at night by opening their pores. These plants then take up carbon dioxide required by them when evapotranspiration is relatively low.

Insufficient Sunlight

Watching for some easy-to-detect symptoms of insufficient sunlight exposure would be best. Here are some of them:

  • Lack of sunlight can cause cacti to become discolored. For example, if your cactus plant is deep green, it will turn pale green or yellowish, which is an easily noticeable symptom indicating that your cactus needs lighter.
  • Insufficient sunlight can cause your plant to stretch towards the light and become ‘leggy.’ In scientific terms, this process is called ‘etiolation,’ simply a plant’s way of reaching out for more light. Etiolated cacti often grow tall in search of light, causing them to become thin and pale. If you notice this happening with your plant, it is recommended to cut off the etiolated growth and place your plant in an area that receives sufficient light. However, etiolation is irreversible in some cases, despite changing the plants’ environment.
  • Root rotting typically occurs due to over watering of your plant. However, it can also be due to a lack of light exposure. Since cacti require low moisture soil to grow in thrive, lack of sunlight leads to the soil drying much slower than it would have otherwise, resulting in it being too moist and damp, leading to the rotting of its roots.
  • Another sign of insufficient sunlight is when your cactus is going on more than one side, which happens when one side of the cactus is exposed to more light than the other. Hence, it is recommended to periodically rotate your cactus, ensuring that all sides receive sufficient light. Pro tip:  if you have decided to change the location of your cactus, do so gradually to allow the cactus to adapt to the new environment.
  • Other signs of your cactus not getting enough sunlight include it looking weak and healthy, the development of brown or black spots, discoloration of its spines, and an overall reduction in the pace of its growth. These signs are easy to detect than the others, and you should act on them immediately to prevent your cactus from dying.

To reverse these effects, increase the amount of direct sunlight exposure each day. However, in doing so, you must ensure that the plant is shaded from the sun for at least a few hours. 

After moving your plant to better light conditions will take about two weeks to recover, so you need not worry. Just don’t give up on it!

How Long Can Your Cactus Survive Without Sunlight?

If you are wondering whether a cactus plant can survive without sunlight, the short answer is no! Like any other plant, they do need sunlight to survive.

As mentioned above, cactus plants typically require at least four hours of direct sunlight to grow and thrive.

A dormant cactus or succulent won’t be affected by lack of watering and sunlight for about two weeks.

Cactus plants do well when they receive gradual light and get direct exposure for prolonged periods. Early morning and late afternoon timings are perfect for allowing gradual sunlight exposure.

It is better to ensure some form of shade is present to avoid sunburns even when they are exposed to direct sunlight. 

During summer and spring, you can place cactus plants in areas there are not too windy or that receive direct rainfall.

Can Your Cactus Survive Outdoors?

If you are wondering whether a cactus makes for a good outdoor plant, the answer is yes! While your cactus plant may thrive indoors, certain species also do well when planted outdoors.

The good thing about cactus plants is that they easily adapt to their environment.

It is recommended to move your cactus plants outdoors during the warm summer months when the temperature at night is around 65 degrees Fahrenheit.

If you are wondering whether a cactus makes for a good outdoor plant, the answer is yes! While your cactus plant may thrive indoors, certain species also do well when planted outdoors.

The good thing about cactus plants is that they easily adapt to their environment.

It is recommended to move your cactus plants outdoors during the warm summer months when the temperature at night is around 65 degrees Fahrenheit.

One of the main advantages of moving your cactus plant outdoors is the increased exposure to better airflow, which allows the roots to dry up. It would be best to manage this transition carefully to avoid over-drying the roots.

The Best Place to Place Your Cactus

To ensure the ideal growth of your cactus, you need to place it in a bright location and receive indirect sunlight.

If you don’t have a bright location in your home, you may need to consider getting artificial light for your cactus plant.

Pick a south-facing window, as this ensures that the cactus receives sufficient sunlight (not too much, not too less).

If you’re on a desert cactus, avoid placing your cactus in a window that is an east- or west-facing window, as this will result in insufficient sunlight exposure.

However, for tropical cacti and succulents, east or west-facing windows would be good enough as they do well in partial shade.

Be careful not to place them in direct sunlight as it will make the plants turn yellow.

You should avoid placing your cactus in the areas like the kitchen and bathroom, where the moisture levels are higher.

While it may be tempting to place your cactus in a location of your choice, you must consider if your cactus will get sufficient sunlight exposure there before moving it.

The placement of your cactus should be subtle and harmonious with the overall theme of your room.