Spike moss, a unique plant often mistaken for true moss, belongs to the genus Selaginella. Its delicate, fern-like foliage, which can form dense mats or upright stems, creates a lush, vibrant green carpet. This distinctive appearance and compact size make it a popular choice for terrariums, shaded garden beds, or as a houseplant.
Essential Care Requirements
Light
Spike moss thrives in consistent, indirect light. A north-facing window provides suitable illumination, as direct sun can scorch foliage and cause browning. Insufficient light leads to leggy growth and dull coloration. Filtered light, like through sheer curtains, mimics its natural habitat.
Watering and Humidity
Consistent moisture is paramount for spike moss, which prefers evenly damp but never waterlogged soil. Overwatering causes root rot, while excessive drying leads to crisp, shriveled foliage. Water when the topsoil feels slightly dry, ensuring thorough saturation. High atmospheric humidity is equally important, as dry air can quickly brown and curl leaf edges.
Maintain high humidity using various methods. A pebble tray filled with water increases localized moisture. Regular misting helps temporarily, but a room humidifier provides the most consistent benefit in dry indoor environments. Grouping spike moss with other humidity-loving plants also creates a supportive microclimate.
Soil
Ideal soil for spike moss offers excellent drainage and moisture retention. A loose, airy mix prevents compaction while holding enough water. Peat moss or coco coir provide a moisture-retentive base. Incorporating perlite or coarse sand ensures aeration and drainage, preventing waterlogging. A slightly acidic pH, typically between 5.0 and 6.0, generally suits spike moss.
Temperature
Spike moss prefers stable, warm temperatures, thriving between 65°F and 75°F (18°C to 24°C). Temperatures below 60°F (15°C) can cause stress and hinder growth. Protect the plant from sudden fluctuations, such as those near drafty windows or vents. Maintaining a consistent environment promotes healthy development.
Fertilizing
Spike moss has modest nutritional requirements and does not need frequent fertilization. Over-fertilizing can lead to salt buildup, burning delicate roots and foliage. During the active growing season (spring and summer), apply a highly diluted liquid fertilizer. A balanced houseplant fertilizer (e.g., 5-5-5 or 10-10-10), diluted to one-quarter or one-eighth strength, is suitable.
Fertilize sparingly, perhaps once every two to four months during warmer periods. Do not apply fertilizer during the fall and winter dormant period. Observe the plant’s growth and foliage color to determine nutrient needs. Yellowing or stunted growth may indicate a need for light feeding, while burnt leaf tips suggest over-fertilization.
Ongoing Maintenance and Common Issues
Pruning
Pruning spike moss is minimal, primarily to maintain shape and remove discolored or dead foliage. Use clean, sharp scissors to snip away yellowed or brown sections. This directs energy to healthy new growth and improves appearance. Extensive pruning is rarely necessary due to its compact growth.
Repotting
Repot spike moss when it becomes root-bound or soil quality degrades, typically every one to two years. Choose a container only slightly larger to avoid excess moisture retention. Carefully remove the plant, gently loosen circling roots, and place it in the new container with fresh potting mix.
Troubleshooting Common Problems
Browning leaves indicate insufficient humidity or inconsistent watering. Increase humidity and ensure consistently moist, not soggy, soil to resolve this. Leggy growth, characterized by stretched stems and sparse foliage, signals inadequate light. Move the plant to a brighter location with indirect light for denser, more compact growth.
Spike moss can occasionally experience spider mites or fungus gnats, especially in dry or overly wet conditions. Regularly inspect foliage for early detection. For spider mites, increase humidity and wipe leaves with a damp cloth. Fungus gnats often indicate consistently wet topsoil; mitigate by allowing the top layer to dry slightly between waterings.
Propagation
Propagating spike moss is straightforward, commonly achieved through stem cuttings or division. For stem cuttings, select a healthy, non-flowering segment 2 to 4 inches long. Ensure the cutting has at least one node, where new roots will emerge. Remove lower leaves to expose the node.
Place the cutting directly into moist, well-draining potting mix, or root it in water. Maintaining high humidity, perhaps by covering it with a plastic bag or dome, significantly improves rooting success. Roots typically develop within weeks, after which the new plant can be cared for as a mature specimen. Division involves carefully separating a mature plant into smaller sections, each with roots and foliage, and potting them individually.