The String of Pearls plant (Senecio rowleyanus) is a popular succulent known for its unique, bead-like foliage. While traditionally grown in soil, Lightweight Expanded Clay Aggregate (LECA) offers an alternative. This article guides you through cultivating String of Pearls in this soilless medium, covering its benefits and specific care.
Benefits of LECA for String of Pearls
LECA consists of porous, inert clay balls offering several advantages for String of Pearls. Its granular structure promotes excellent air circulation around the roots, reducing root rot risk, a common issue in dense soil. LECA also provides consistent moisture through capillary action, ensuring roots access water without waterlogging.
Growing String of Pearls in LECA can reduce pest issues, as many soil-borne pests thrive in organic matter absent in LECA. This cleaner environment also means less mess and fewer fungus gnats. Furthermore, LECA does not break down like soil, allowing plants to remain in the same container longer, minimizing repotting stress.
Transitioning Your Plant to LECA
Begin by carefully removing your String of Pearls from its soil pot. Gently loosen the root ball and rinse away all soil under lukewarm running water. This step is important because old soil can promote root rot in the new LECA environment. Inspect the cleaned root system for rot or damage, trimming soft, mushy, or discolored sections with clean, sharp scissors.
Before planting, rinse LECA thoroughly to remove dust, then soak for at least 24 hours. This saturates the LECA for effective wicking. Fill your chosen pot, preferably with drainage holes, about one-third full with the pre-soaked LECA. Position your plant on this base, spreading its roots evenly.
Gently fill the remaining space with LECA, covering the roots but leaving the plant’s neck exposed to prevent stem rot. Do not pack the LECA too tightly, as this restricts airflow. After securing the plant, fill the pot with water until it reaches about one-third up the LECA layer. This initial watering helps the plant acclimate by allowing the LECA to wick moisture to the roots.
Ongoing Care in LECA
Maintaining the correct water level is key for String of Pearls in LECA. The LECA pellets should always sit partially submerged, typically about one-third up the pot, allowing the plant to wick moisture. Refill the reservoir when the water level drops below the LECA, generally checking weekly, though frequency varies with conditions and plant size.
As LECA is inert and contains no nutrients, a complete hydroponic nutrient solution is necessary. String of Pearls does not require heavy feeding; a diluted, balanced liquid fertilizer every few weeks during the active growing season (spring and summer) is sufficient. Using filtered or distilled water for your nutrient solution prevents mineral buildup from tap water.
String of Pearls thrives in bright, indirect light, whether in soil or LECA. Place your plant where it receives ample ambient light, avoiding harsh, direct sunlight that can scorch its pearls. Stable temperatures between 70-80°F (21-27°C) are best for growth.
Flushing the LECA periodically prevents mineral salt buildup from the nutrient solution. This involves draining the reservoir and running plain water through the LECA to rinse away accumulated salts, typically every four weeks or when adding new nutrients. This practice maintains a healthy root environment and prevents nutrient lockout, where the plant cannot absorb available nutrients due to high salt concentrations.
Addressing Common Challenges
Even in LECA, root rot can occur if the water reservoir is consistently too deep, submerging stems, or if water becomes stagnant. Root rot bacteria thrive in oxygen-deprived environments. If stems become mushy or discolored, remove the plant, trim affected roots, and adjust the water level so only the bottom third of the LECA is submerged.
Yellowing leaves or stunted growth often indicate nutrient deficiency, as LECA provides no inherent nutrition. If your plant shows these signs, verify you are using a balanced hydroponic fertilizer at the correct dilution and frequency. The nutrient solution should contain minerals like calcium and magnesium, often lacking in filtered water, which are important for cell wall strength and photosynthesis.
Dehydration or shriveling of pearls can happen if roots don’t get enough water, even in LECA. This occurs if the water level drops too low or if the plant is still acclimating and hasn’t developed sufficient water roots. Regularly check the water reservoir and ensure the LECA wicks moisture effectively; a clear pot helps monitor this.
Algae growth in the water reservoir is a common aesthetic issue, especially in clear pots exposed to light. While generally harmless in small amounts, excessive algae can compete for nutrients and indicate too much light. To mitigate algae, use an opaque outer pot or regularly clean the reservoir and change the water. Lack of new growth might signal insufficient light or a need for consistent nutrient supply during the growing season.