Succulents are plants known for their fleshy leaves or stems, which store water in specialized tissue called parenchyma. This adaptation allows them to survive in arid environments where water is scarce and makes them highly resilient to drought. Light exposure is the most significant factor in their care after proper watering. Succulents require significant light to thrive, but the specific intensity and duration must be carefully balanced to prevent damage.
General Sun Requirements
The light requirements for succulents are generally high, reflecting their native habitats, which are often sun-drenched semi-deserts. Most common varieties need a minimum of six hours of bright light daily for proper growth and a compact shape. The ideal condition is often bright indirect light or a few hours of gentler morning sun, particularly in hotter climates.
Direct midday or afternoon sun can be too harsh for a succulent that has not been conditioned to such intensity. When moving a plant from a low-light indoor setting to a brighter spot outdoors, a process of gradual acclimation, sometimes called “hardening off,” is necessary. This involves slowly increasing the duration of direct sun exposure over several weeks, which allows the plant to build up its protective pigments and prevent immediate scorching.
Recognizing Signs of Light Stress
Troubleshooting a succulent’s health often begins with examining its physical structure for signs of incorrect light exposure.
Etiolation (Not Enough Light)
When a succulent does not receive enough light, it exhibits a phenomenon known as etiolation. The plant will begin to stretch rapidly toward the nearest light source, resulting in a pale, elongated stem with widely spaced, smaller leaves, losing its naturally compact rosette shape. This weak, pale growth is lighter green because the plant is producing less chlorophyll. The stretched growth caused by etiolation is permanent and cannot be reversed by simply adding more light later.
Sun Stress and Sunburn (Too Much Light)
Conversely, too much sun can cause two different reactions: sun stress or actual sunburn. Sun stress is a protective measure where the plant produces pigments like anthocyanin, causing the leaves to turn vibrant shades of red, pink, or purple. This color change indicates the plant is receiving strong light and is typically desired by growers. Actual sunburn is more damaging, appearing as permanent, rough, white, tan, or dark brown patches on the leaves. This tissue damage is irreversible and requires moving the plant to a slightly shaded area until new, undamaged growth appears.
Optimizing Indoor Light Conditions
For indoor growers, light placement relative to windows is the single biggest factor in a succulent’s health. South-facing windows offer the most intense and sustained light exposure, often providing enough light for even the most sun-loving varieties. East-facing windows provide the gentler morning sun that is generally safer, while West-facing windows offer intense afternoon sun that can cause sunburn. North-facing windows are typically insufficient for almost all succulents.
When natural light is limited, supplemental grow lights become necessary to prevent etiolation. Full-spectrum LED lights are highly effective because they mimic the sun’s photosynthetic spectrum and produce little heat. Succulents generally require a light cycle of 12 to 14 hours per day under a grow light to simulate natural summer conditions and promote compact growth. Placing the light source at the correct distance helps ensure the intensity is high enough without causing damage, typically 6 to 12 inches away for fluorescent lights or 18 to 24 inches for LEDs.