Succulents are drought-tolerant plants that store water in their fleshy leaves and stems. Moving them outdoors often leads to richer coloration and stronger growth, as they benefit from higher light intensity and better air circulation than is typically found indoors. Successfully growing these plants outside requires adapting common indoor care habits to account for the variable and sometimes harsh nature of the natural environment. The primary challenge outdoors is managing exposure to uncontrolled elements like rain, intense sun, and temperature extremes.
Establishing the Right Environment
Outdoor succulents need abundant light to maintain their compact shape and achieve their best color. Most varieties thrive in a location that provides bright, indirect light for the majority of the day or direct sun during the milder morning hours. A sudden transition from a shaded indoor spot to intense afternoon sun can cause immediate scorching, appearing as white or black burn patches on the leaves. Sensitive types, like many Echeveria, require protection from the harshest midday rays, while others, such as Sempervivum, are more tolerant of full sun exposure.
The composition of the soil is the most important foundational requirement for outdoor success, especially where natural rainfall is a factor. Succulents require a growing medium that promotes fast saturation and acute drainage, preventing the roots from sitting in prolonged moisture. The ideal mix mimics their native arid habitats, consisting of significantly more mineral content than organic matter. A good ratio is often one part organic material (like potting soil or coir) to three parts inorganic material (such as perlite, pumice, coarse sand, or grit).
This gritty blend ensures superior aeration around the roots and prevents the compaction that leads to root rot. Pumice is often preferred over perlite for outdoor containers because its heavier weight provides better anchoring against wind. Using containers with large drainage holes is necessary for all outdoor succulents, allowing excess water to escape immediately after soaking.
Mastering Outdoor Watering Techniques
Outdoor watering must be guided by the “soak and dry” method, which mimics the flash-flood and drought cycles of the plants’ natural environment. When watering, the soil should be thoroughly saturated until water flows freely from the drainage holes, ensuring the entire root ball receives moisture. It is crucial to allow the soil to dry out completely before initiating the next watering cycle, which can be confirmed by checking the soil at least two inches down.
The frequency of watering is highly dependent on environmental factors like heat, wind, and ambient humidity, making a calendar-based schedule unreliable. During the active growing season, higher temperatures and increased air movement will dry the soil more quickly, often requiring more frequent deep soaks. Conversely, many succulents enter a period of dormancy during the winter, requiring significantly less or even no water when temperatures are low. Overwatering during dormancy is hazardous, as the plant is not actively using moisture and the soil takes much longer to dry, increasing the risk of fungal root rot.
Protecting Succulents from the Elements
Outdoor succulents face two primary environmental threats: freezing temperatures and intense heat. Most popular varieties, including Echeveria, are warm-climate plants, typically hardy only to USDA zones 9 to 12, meaning they cannot tolerate freezing. Even a short period below 32°F can rupture the plant cells due to the water stored in the leaves, causing irreversible damage. For these non-hardy plants, container gardening is the best strategy, allowing them to be moved to a protected location, such as a covered patio or garage, when frost is predicted.
For succulents planted directly in the ground or for short-duration cold snaps, temporary protection is necessary. Covering the plants with a breathable material, such as a frost cloth or old bedsheet, before nightfall can provide several degrees of warmth and prevent frost crystals from forming on the foliage. Remove the covering during the day to allow for light and air circulation.
In contrast, extreme heat can lead to sun scorch, particularly on varieties with delicate coloration or those recently moved outdoors. Providing temporary afternoon shade or positioning sensitive plants where they receive only morning sun helps prevent this heat stress. Prolonged heavy rain also poses a threat by pushing the soil past its saturation point, even with excellent drainage. During extended wet periods, move container plants under eaves or a covered area to prevent constant saturation, which manages humidity and reduces the risk of fungal diseases.
Managing Pests and Diseases
Succulents grown outdoors may become targets for various common garden pests, though healthy plants are typically less susceptible. Mealybugs are a frequent problem, appearing as small, cottony white masses that cluster in the crevices between leaves and stems, sucking the plant sap. Another potential issue is the presence of aphids, which are often found on new growth and flower stalks, excreting a sugary honeydew that can lead to sooty mold.
Fungus gnats are small, dark flies that are less harmful to the plant itself, but their presence indicates the soil is remaining moist for too long, which is a sign of potential overwatering. Targeted, non-toxic treatments are the first line of defense for these pests. Small infestations of mealybugs can be managed by dabbing them directly with a cotton swab soaked in isopropyl alcohol, while a strong jet of water can often dislodge aphids.
The most common disease is fungal root rot, which is directly linked to poor drainage and overwatering, especially in cooler, humid conditions. This condition causes the roots and lower stem to become soft and black, and the plant will often wilt despite being watered. Prevention through proper soil and watering techniques is the most effective approach, as advanced rot is often fatal. If caught early, removing the plant, trimming away all soft, discolored root material, and repotting in fresh, dry, gritty soil may save the plant.