Sun-loving plants are at their core succulent plants.
That’s a good thing, as it would be nearly impossible to survive in those arid and desert environments without an appreciation for sunlight.
There are a few factors to consider when considering lighting requirements for succulents and cacti, especially if you want the best Instagram pictures.
How Much Light to give Succulents
Light is hard to measure since it is intangible.
There’s no way to give a plant 7 lbs. of organic, free-range light every day with 1 cup of water or 1 tablespoon of perlite in a soil mix.
We define optimum duration simply by measuring the amount of time with exposure to light each day.
And to make matters worse, there’s the question of how much natural light, what quantity of artificial light, whether it should be diffused, bright or direct. It’s very complicated.
Succulents prefer about 10 to 14 hours of light a day, and let’s simplify things by starting with a baseline.
You can only assume that it’s not one of those shade-loving succulents like Sansevieria trifasciata (the Snake Plant) that would fry if you gave it so much light.
The plants need rest too, which is why they need more light and 24-hour-a-day light.
The same way people go to bed at night to fix their brains and muscles, plants undergo certain processes in the dark that the other species does not.
A fun fact about succulents is that most of them need the dark to photosynthesise. They take in carbon dioxide during the night, and store energy during the day.
If you stayed awake for 24 hours, I wouldn’t want to hold my breath, would you?
Do not expose your plants to more than 14 hours of light a day. 12 hours of light is really enough to make anyone happy.
However, it is risky for succulents and cacti to survive in areas with less light. This may lead to their etiolation.
ETIOLATION, also known as ‘stretching’ or ‘legginess’, is a shining example of plant behavior at work.
Aren’t animals the only ones with behaviors?
I can’t think of a better way to describe it. Plants are intuitive enough to know where their light comes from and where to find it.
Thus, they grow their stem/trunk/branches towards light very rapidly by lengthening some cells, shortening others, and bend and twist them into the light source.
Plants usually slow down or stop leaf production during the etiolation process. This makes sense – there’s not enough light anyway, why bother?
It might even be top-heavy and susceptible to damage from falling over and becoming damaged as a result of etiolation.
The plant looks ugly now, but it is not unhealthy. Plants in the wild grow etiolated when they are shaded. As soon as they find that sweet spot of light, they resume regular growth.
Once a succulent, or any plant, has grown all stretched-out, it will remain that way for the rest of its life.
Reversing growth is like dying, right?
But there is some good news too! We’re talking about succulents and cacti, a hardy group beloved for their easy propagation. You can “fix it” by growing another plant, sort of.
Take an etiolated Echeveria for instance: It gets long and skinny with sparse leaves and bare stems when etiolated. When you cut it over the rosette, you can let it calluses quickly, then take it back outside.
It’ll turn into a normal-looking Echeveria if you give it enough light the second time around.
Additionally, even though you didn’t leave any leaves on the other half, it’ll probably start to grow some new rosettes!
Generally, this method works best on rosette-type succulents, although it can be used on other groups as well.
Seasonal Light Differences
Seasons bring various levels of light and intensity.
Summer days can get pretty long, and the light can be pretty strong too. Most succulents thrive in these conditions, but if you live in an area characterized by extreme summers, you should take some extra precautions.
It might be necessary to supplement your succulents with more light than they would get otherwise sitting on your windowsill if the days are shorter and they aren’t dormant in winter.
Succulents and cacti are rotated between the indoor and outdoor spaces as the seasons change. While succulents will enjoy the bright sunlight during the summer, temperatures below freezing will normally kill them.
Sunlight vs Artificial Light
There are so many variables in this question that I could probably write an entire book about it alone!
Also, it’s a particularly interesting comparison. A lot of science comes into play, but also a fair amount of personal preference.
A succulent grower can use a mixture of sunlight and artificial light. In certain circumstances, one is superior, but in general, they are both useful tools.
You can just put succulents on your windowsill and water them when you remember and they will flourish because sunlight is right there. It’s great!
The big, blazing ball of fire hanging in the sky has been there for a couple of billion years. All life on Earth has prepared itself for it, and in the case of plants and succulents, is able to harness it.
Plants are born to bathe in sunlight, and they have crazy colors that enable them to absorb different wavelengths. They use these colors and adaptations to protect themselves and to channel sunlight into their tissues.
The sun is always the perfect light source for succulents.
Maximizing Natural Light Indoors
The natural light waxes and wanes as the day progresses, and as the seasons change.
For succulents and cacti, the natural cycle works really well – morning light is usually very intense, and it disappears in the afternoon.
For those of us in the northern hemisphere, a south-facing window provides the best light. It has more hours of daylight than any other direction. Conversely, a north-facing window receives the least.
East and west windows are ideal for plants that prefer partial sun. The sun rises in the east and is at its strongest during the first part of the day. West windows (and north windows) work best for plants that prefer full sun.
It’s important to take into account external factors such as trees or buildings that will cast shade on your windows. And place your plant as close to the glass as possible – every inch means increased light and happier cacti.
Glass blocks or diffracts significant amounts of light, so any accumulated grime can seriously hinder light transmission.
Mirrors bounce light around and magnify the effect of natural light in the room and on your plants. A mirror near the window will have a substantial effect on the light in the room and on your plants.
Consider adding a windowsill shelf or hanger to your best real estate when you eventually run out of space. They double or triple your space without taking up much space.
Sun-Stress or Sun-Blush
This is one of the coolest things about succulents – some change color in the sunlight!
The process is known by a few different names, but usually I call it sun-stress because it’s a much more accurate description of the phenomenon. Some succulent plants exhibit a defensive reaction to harsh sunlight and UV light.
It indicates they’re probably healthy when sun-stressed. In fact, when it happens, they’re not in any danger!
Perhaps you noticed the color of the plants you purchased online wasn’t quite the same as pictured or they faded after a couple of weeks.
You see colorful succulents on Pinterest, but they are probably green without being exposed to much light.
Here’s a hybrid Aloe commonly known as Christmas Carol Aloe.
In order to get your succulents and cacti bright colored, you can simply expose them to direct sunlight. Within a couple of weeks, you should be able to see their true colors (if they are indeed a color-changing variety).
Generally, artificial light is harder to achieve the same pretty colors. The intensity of the light and sunlight in the ultraviolet portion of the spectrum plays a big role in the change.
It’d be hard to replicate UV light, and intense light isn’t generally a feature of artificial light. Full-spectrum bulbs do a pretty decent job at mimicking sunlight – so those would be your best bet.
The plants can also get sunburned, you know!
Although succulents are more resistant to sunburn than other plants, they can still get burned. It’s generally only an issue in a couple of circumstances.
Most succulents can’t handle the heat, especially shade-loving ones. Strong, direct light could cause them to burn.
Leave water drops on the leaves of plants and they might magnify strong sunlight – causing the plant to burn. It’s usually not an issue, but it’s wise to water at the base of the plant just in case.
The leaves of some succulents, many Echeveria especially, have a “farina” that smudges when you touch them. That stuff protects from intense sunlight, and so it should be kept away from hands and fingers.
How would a succulent sunburn look?
On most plants, sunburn manifests as a light browning on the leaves that quickly becomes severe if it doesn’t get relief. It usually starts around the edges and they become crispy pretty quickly once the process has begun.
A sunburn may appear as small brown spots (especially if water was left on the leaves).
Leaf curling is another telltale sign that the plants are receiving a lot of sun and are at risk of being burnt.
Sunburn isn’t difficult to avoid, but it can be annoying. Most succulents and cacti will survive a day of intense sun, if they are accustomed to it.
Acclimatization is a gradual process. If a plant has been indoors or in the shade for a long time, it is well-accustomed to those conditions. Suddenly moving it into the sun is a recipe for disaster.
For two weeks, give it more light every day. Whether that means moving it to a place with less shade or taking it outside repeatedly, the plant should experience longer periods of light and more intensity of light each day.
It is possible to use shade cloths of varying thicknesses for this process as well!
A lot of great things can be said about artificial lighting, but natural light has its advantages as well!
If you’re like me, you’re running out of windowsill space. Light doesn’t penetrate deep enough into houses for succulents not sitting next to a window.
In places with a cold winter, most succulents cannot survive outside. You’ll have to bring them inside for several months. They still need light inside, of course, otherwise they may die from etiolation.
Since artificial lights aren’t too intense or bright, they’re better for propagating plants since they’re also not too bright. You can even use specific wavelengths of light to encourage flowering or fruiting.
The bulbs or electricity aren’t free, unfortunately. They do require a small upfront investment, though, and allow you some flexibility in how you place your plants.
There are still many recent and interesting articles about Snake Plants..
..as well as other unique information from All Things Gardener..
For further information and other inquiries..
..you can contact us here