How much light succulents need depends on the type of plant and where you live. Most haworthias and gasterias prefer shade but can handle some sun along the coast. Many but not all cacti are fine in full desert sun. As a general rule, the majority of soft-leaved succulents want half a day's sun (in mild climates) and dappled or "bright" shade.
Light is essential to any plant's survival, but too much can damage it. Too little can ruin its shape. Providing optimal light often comes down to observation.
If these plants could talk, they'd say, "The light is over there." When succulents lean, it's usually because they're seeking more sun. The phenomenon of growing toward light is "phototropism." Stretched growth in low-light situations is "etiolation."
This aloe closed its rosette to protect it's vital core from too much sun and resulting dehydration. Pigment similar to that of autumn leaves protects it from burning. The plant is "stressed" -- not necessarily a bad thing. It'll recover when the rains come and sun is not as harsh, just as it would in the wild.
This large agave in my garden has leaves that bend and curve. Stretched cells are vulnerable to sunburn. There's nothing I can do to prevent it, short of trying to move an enormous succulent or planting a tree to shade it. I don't like looking at burned patches, so I trim the damaged leaves back to the trunk.
These neglected echeverias have flattened their leaves to expose more surface area to available light. The plants' are coping as best as they can to being indoors. The answer is not to put them outside in full sun because they'll burn, just as you would if you're pale then sunbathe too long. They'll need to be "hardened off" to greater sun gradually.
Hot, sunny days came on the heels of spring last year, and plants in my garden didn't have time to adjust. I could have prevented sunburn on these aeoniums if I'd tossed a sheet or frost cloth on them. They eventually outgrew the damage, but it was evident for months.
This Agave 'Cream Spike' has recovered from sunburn. You can still see the damage on the outer leaves, but new growth is fine.
Here's another sunburn survivor. The damaged tissue is white and the new growth, green.
Above: Etiolated echeverias.
Above left: Aloe maculata, late summer; right: same plant in spring.
Related info on this site:
How to make Succulents Bloom
Succulents (most plants for that matter) need light in order to flower. Sun is essential to photosynthesis, which creates energy and fuels new growth. All plants (actually, all living things) want to reproduce...[Continue reading]
How to Stress Your Succulents (And Why You Should)
Plenty of sun brings out brilliant reds and yellows in certain succulents, but how much to “stress” the plants varies depending on... [Continue reading]
How to Keep Succulents Happy Indoors
Place your succulents near a window. Maximum sun exposure is on the south and west sides of your house. The farther north you live in North America...[Continue reading]
During rainy weather, succulents, which come from arid climates, may rot. Stems or trunks turn squishy and collapse. It may be possible to take cuttings from healthy top growth and restart the plants—as I did after one rainy winter with aeoniums. Fortunately, the rest of my succulents came through fine, despite double normal rainfall. After…