Sundew plants, with their glistening, sticky tentacles, are fascinating carnivorous species that capture insects for nutrients. A loss of their characteristic “dew” often signals an underlying issue. This guide helps diagnose and resolve common problems leading to a lack of mucilage production, restoring your sundew’s health.
Understanding Sundew Stickiness
The “stickiness” on sundew leaves is mucilage, a clear, viscous fluid produced by stalked glands or tentacles covering the leaves. These glistening droplets attract small insects, which become ensnared.
Once trapped, the sundew’s tentacles slowly bend to envelop the prey, facilitating digestion. The plant then secretes digestive enzymes to break down the insect, absorbing essential nutrients like nitrogen and phosphorus, scarce in their natural bog habitats. This carnivorous adaptation supports the sundew’s health and growth, supplementing limited soil nutrients.
Common Causes for Loss of Stickiness
Improper Water Quality
Sundews are highly sensitive to water’s mineral content, naturally growing in nutrient-poor, acidic environments. Tap water, bottled water, or some well water introduce toxic dissolved minerals and chemicals. Over time, these impurities build up in the soil, inhibiting mucilage production and potentially damaging roots.
Insufficient Light
Adequate light is a primary factor in mucilage production, as sundews require significant energy to create their sticky dew. Insufficient bright light causes leaves to appear green and lack vibrant coloration. This directly impacts photosynthesis, reducing energy for secreting the adhesive fluid.
Low Humidity
Sundews thrive in high humidity, mimicking their natural bog and marsh habitats. Dry air causes mucilage droplets to evaporate quickly before forming or accumulating. Persistent low humidity prevents visible dew, making the plant appear dry and non-sticky.
Temperature Extremes
Extreme temperatures stress sundews, negatively affecting mucilage production. Excessive heat increases transpiration, causing dew to evaporate rapidly, while prolonged cold damages plant tissues. Sundews prefer warm, moist conditions; deviations from this range reduce stickiness.
Natural Dormancy
Some temperate sundew species naturally enter dormancy during colder winter months. During this phase, growth slows significantly, and dew production may stop, with leaves often dying back. This is a normal survival mechanism, not poor health, triggered by environmental cues like shorter daylight hours and cooler temperatures.
General Plant Stress
Various stressors can temporarily impact mucilage production. Recent repotting causes transplant shock, leading to a temporary cessation of dew as the plant recovers. Sudden environmental changes (light, temperature) or pest infestations can divert energy from mucilage synthesis, resulting in stickiness loss.
Restoring Stickiness and Ongoing Care
Adjusting Water
To restore mucilage production, consistently use only pure, low-mineral water like distilled, rainwater, or reverse osmosis water. Implement the tray method: place the pot in a saucer with 0.5 to 1 inch of water, allowing the plant to absorb moisture from the bottom. This keeps the soil consistently moist without waterlogging, which is important for root health.
Optimizing Light
Provide your sundew with ample bright light, a significant factor in dew production. Most sundews benefit from at least four to six hours of direct sunlight daily, or strong artificial grow lights indoors. Position indoor plants in a sunny south-facing window or use full-spectrum LED grow lights 12-18 inches above the plant for sufficient intensity. Gradual acclimation prevents sunburn and allows the plant to adjust.
Increasing Humidity
Elevating ambient humidity helps prevent mucilage evaporation and encourages dew formation. Placing the plant in a terrarium or using a humidity dome creates a consistently moist microclimate. Alternatively, a pebble tray filled with water beneath the pot (without contact) increases local humidity as water evaporates. Frequent misting offers temporary relief but should not replace other humidity-increasing methods.
Managing Temperature
Maintain a stable temperature range suitable for your sundew species, between 68°F and 95°F (20°C to 35°C) for many common varieties. Protect plants from extreme heat, cold drafts, or sudden temperature fluctuations. A slight temperature drop at night (10-20°F) can also contribute to plant vigor and consistent dew production. If outdoor temperatures are too low, bring plants indoors or provide adequate protection.
Accommodating Dormancy
For temperate sundew species, respect their natural dormancy period, which usually occurs in winter, by adjusting care. Reduce watering frequency, allowing the soil to remain damp rather than constantly wet. Provide cooler temperatures, between 35°F and 50°F (1°C to 10°C), for the plant to rest and conserve energy for vigorous spring growth.
Promoting Overall Health
Beyond environmental adjustments, promoting overall plant vigor helps maintain consistent dew production. Avoid fertilizers, as sundews obtain nutrients from insects and are sensitive to chemical salts. If growing indoors without insects, occasional feeding of small insects like fruit flies or rehydrated fish flakes provides supplemental nutrients. Regularly inspect your plant for pests or stress, addressing issues promptly to ensure continued health.