Succulents store water in fleshy leaves, stems, or roots and are often associated with bright, arid environments. They can be placed outside in the sun, but this transition requires careful consideration and a specific process. While these plants require significant light exposure for healthy growth, moving them directly from an indoor setting to harsh outdoor sunlight will likely result in permanent tissue damage. The success of outdoor placement depends entirely on the specific variety of succulent and how it is gradually introduced to the elements.
Factors Determining Sun Tolerance
A succulent’s capacity to tolerate full, direct sun is highly dependent on its specific species and physical characteristics. Varieties like Sempervivum (Hen and Chicks) and many Sedum types are naturally resilient and can handle full-day sun exposure, even in hot climates. Conversely, species such as Haworthia and Gasteria are prone to burning if exposed to intense midday sun, as they originate from environments where they are sheltered under larger plants.
The plant’s coloration offers a reliable clue regarding its sun tolerance. Succulents that develop red, purple, or orange hues contain protective compounds that enable them to withstand more direct sunlight. These vibrant colors are a natural stress response that shields the plant from intense UV radiation. Plants that remain dark green, indicating a high concentration of chlorophyll, are more susceptible to sun damage and thrive better in bright, indirect light or morning sun only.
The plant’s history is another factor, as a succulent grown indoors or in a greenhouse is not prepared for unfiltered sunlight. Indoor light is significantly less intense than direct outdoor sun, even on a sunny windowsill. An abrupt move outside will shock the plant, regardless of its species, making the controlled introduction process mandatory for survival.
The Essential Acclimation Process (Hardening Off)
The process of safely moving a succulent from a protected environment to outdoor sun is called “hardening off,” and it is mandatory to prevent scorching. This transition should begin in the spring or early summer after the risk of frost has passed, allowing the plant time to adjust before the peak heat of summer. The entire acclimation process typically takes between seven and fourteen days.
Begin by placing the succulent in a sheltered location that receives bright, filtered light or partial shade, such as under a covered porch or a tree canopy. On the first day, expose the plant to direct morning sunlight for only one to two hours, as morning rays are less harsh than midday or afternoon sun. Monitor the plant closely for any signs of distress or color change during this initial period.
Over the next one to two weeks, gradually increase the duration of direct sun exposure by about an hour each day. For example, on day three, the plant might receive three hours of morning sun before being moved back to its sheltered spot. This slow increase allows the plant cells to develop a thicker cuticle, the protective, waxy layer on the leaves that guards against intense light and water loss. By the end of the two-week period, the succulent should handle its intended level of outdoor sun exposure without sustaining damage.
Identifying and Addressing Sunburn
Sunburn occurs when a succulent is exposed to more intense light than it can tolerate, and the resulting damage is irreversible. Minor sun damage often appears as pale, bleached, or whitish spots on the leaves. This discoloration indicates that the plant’s chlorophyll has been destroyed by excessive UV radiation.
More severe damage presents as brown, black, or dry, crispy patches, signifying cell death within the leaf tissue. Distinguish this from the healthy red or purple stress coloring that some varieties develop for protection. Sunburn spots feel rough or dry and will not disappear; they are permanent scars on the plant.
The immediate corrective action for a sunburned succulent is to move it to a location with bright, indirect light or partial shade. Do not move it to complete darkness, as this can cause further shock. The damaged leaves will not heal, but the plant can continue to grow normally, with healthy new growth emerging from the center. Allow the damaged leaves to remain until they naturally shrivel and fall off, as removing them hastily can stress the plant further.
Outdoor Care and Seasonal Considerations
Once a succulent is acclimated to its outdoor environment, its care routine must be adapted to account for the increased light, heat, and air circulation. Outdoor succulents require more frequent watering than indoor plants because the sun and wind accelerate moisture evaporation from the soil. However, the fundamental rule remains: water deeply, but only once the soil has completely dried out.
During periods of extreme summer heat, especially when temperatures exceed 90 degrees Fahrenheit, even sun-tolerant varieties benefit from temporary shade. Providing a shade cloth or moving potted plants to a location that offers afternoon shade prevents heat stress and potential scorching. Poor drainage is a major risk outdoors, so ensure all containers have drainage holes. In-ground plants must be in a well-draining soil mix to prevent root rot from excessive rain.
As the season changes, preparation for cold weather is necessary, particularly for “soft” succulents, which are not frost-tolerant. Most soft varieties, such as Echeveria and Crassula, will not survive temperatures below 40 degrees Fahrenheit and must be brought indoors before the first expected frost. Hardier varieties, like some Sedum and Sempervivum species, can withstand freezing temperatures. Even these hardier types may benefit from a layer of mulch for root protection during the coldest months.