Indeed, cacti can suffer from too much direct sunlight, which can cause severe problems. Sunlight is required for proper plant development, but too much of it can hurt the plant’s anatomy leaves and stems will begin to change colors to orange and brown.
In severe cases, cacti can receive a sunburn from very harsh direct sunlight exposure.
Sunburn will make the affected area look calloused and rougher than the surrounding cactus; the area will be brown and calloused.
You can cut out the stem or leaves of the plant affected by sunburn, but the sunburn will stay on the stem or leaves of the affected area.
In any case, if your cactus has been affected, the best course of action is to move it to an area with shade away from direct light.
If you do not have location options, especially in an area of the house that does not experience direct sunlight, take the time to readjust the cactus to its environment.
This resizing option can be as easy as gradually pulling the distance between the cactus and the light source for one or two weeks.
Take Note: if your cactus displays callouses, or evidence of sunburn, or has changed colors, it simply means you are still overstressed from sunlight exposure.
Is Direct Sunlight Necessary for Cactus Growth?
No, most cactus varieties do not need direct sunlight to grow.
In fact, most succulents thrive with adequate light and cooler spaces with no direct sunlight.
If you grow your cactus indoors, it is best to position them near an east to south-facing window with ample light.
If you have the cactus outdoors, locate an area in the yard with shade to limit their exposure to direct sun.
Individual cactus species can tolerate direct sun for several hours based on their region of origin, while most cactus will sunburn with prolonged sun exposure.
However, some cactus have adapted different ways to tolerate enduring intense direct sun and heat.
For your outdoor cactus, you should place them under taller plants prior to moving them to areas where they will be exposed to direct sunlight.
The goal is to help increase their exposure to the sun laid out over a period of time to reduce heat shock, sunburn, and callousing.
Did you know? Most modern species such as the Coral Cactus and Mistletoe Cactus are very sensitive to scarring and sunburn.
How Does a Cactus Adapt to Varying Sunlight Exposure?
Cacti that have many spines are well suited to intense sunlight, while cacti that are considered house plants, tend to be more sensitive to sunburn and hard setting when encountering intense sunshine from out door conditions.
For example: It’s always good to try maintain ways of letting your cactus acclimate to direct sunlight until you are ready to intensify the heat level.
You need to allow young cactus time before moving them outside as they do not grow well under intense heat conditions.
Finding the best location for your cactus to be in the proper outdoor sunlight is difficult tea the rays of the sun actually feel touch bodies in a different way at various times of the day.
For example: some young cactus will tolerate a lot of sun, while other young cacti do better with somewhat less heat than the morning sunlight and less sun during the evening time.
You only need to expose your cactus to six hours of direct sunlight for optimum growth as cacti do not mind heat if proportional outside sunny and bright areas.
When cactus are deprived of sun light exposure, they usually appear to show several signs of etiolation, while elongation is an efficient mechanism for adaptation, it will prevent true growth of the cactus with shallow stems.
Cacti that are not abiding appropriately to sun light may also change or revert back from their original colored stems to a more dull or green color.
On the contrary, Cactus that are subjected to sunlight show several much brighter colors and strong stems and developing leaves.
In my experience, Cacti should be monitored with the light exposure for heat that assists in noting what the cacti are actually supposed to look like too for development patterns and when they will product better quality.
How Temperatures Influence Cactus Growth
Temperature frequently impacts the rate of water uptake in the cactus; warmer temperatures increase the rate of water uptake and cooler temperatures could possibly slow down the process.
Cool soil temperatures can also result in root rot if the cactus is left in the same position for long periods of time.
Thus, always monitor temperatures changes and soil texture before watering; do not water until the soil has had the chance to dry out.
If you live in a region that normally experiences cooler temperatures, your cactus may require watering once every month at this time due to a slow rate of water uptake.
As mentioned previously, warm temperatures will increase rates of water uptake which could impact growth patterns in your cactus.
If for example, you place your cactus near a window, increased temperatures may lead to sunburn.
Besides Sunlight, What Else Do Cactus Require to Flourish?
Cacti need other elements for growth such as water and a suitable temperature.
Although your cactus is more tolerant of less water to survive, water is necessary for the cactus to grow.
If your cactus is experiencing dry spells add water when the stem looks shriveled and when it is not growing.
Always apply plenty of water when watering the cactus. If the water is gone quickly, add more water until the cactus stops drinking the water.
Cacti typically need watering no less than every other week. However, if you don’t supply enough water the leaves will discolor, fade, and pucker.
Excessive water can cause the cactus to be mushy and develop root rot, or the stem can start to appear brown.
Final Thoughts
Though the cactus may be a desert-based plant, there is only so much sunlight it can actually handle.
It mostly depends on the species; for example, the prickly pear cactus can handle full sun exposure; on the other hand, the coral cactus does better in moderate sun exposure.