Temperature
Thermoregulation: A Guide to Carnivorous Plant Temperatures
Temperature is one of the most defining factors for success with carnivorous plants. From icy bogs to humid jungles, these plants have evolved within specific thermal ranges that act as an invisible environmental switch, controlling their growth, dormancy, and the production of their stunning traps.
This guide gives you the ideal temperature ranges by genus and provides the explanations behind these crucial requirements.
The Science of Temperature: Metabolism & Survival
Temperature dictates the speed of a plant’s metabolism, the complex web of biochemical reactions that sustain life. Each plant species has evolved a metabolic rate that is optimized for a specific thermal window.
- Diurnal Range: The difference between day and night temperatures. This drop is a vital signal that tells a plant how to regulate its energy and growth.
- Dormancy: A state of reduced metabolic activity. For temperate plants, this is a survival mechanism that allows them to conserve energy during cold winters.
Temperature Needs by Genus
| Genus | Ideal Day Temp | Ideal Night Temp | The Science Behind It |
| Venus Flytraps & Sarracenia | 70–95°F (21–35°C) | 50–70°F (10–21°C) | These temperate plants are genetically programmed to a yearly cycle of growth and rest. The cold winter temperatures trigger a state of dormancy, which is essential to prevent the plant from exhausting itself and ensures a vigorous return in spring. |
| Sundews |
Temperate: 65–85°F Tropical:70–90°F |
Temperate: 40–60°F Tropical:55–75°F |
The wide range of sundews reflects their adaptability. Temperate species require a cool dormancy period, while tropical species like D. capensis will grow year-round, as their metabolism is adapted for consistent warmth. |
| Highland Nepenthes | 70–80°F (21–27°C) | 45–60°F (7–16°C) | These plants are native to high-altitude cloud forests. The significant night drop is an essential metabolic cue that helps them regulate their energy and triggers the production of their iconic pitchers. |
| Lowland Nepenthes | 80–90°F (27–32°C) | 70–78°F (21–25°C) | Lowlanders have evolved a high-speed metabolism that requires consistent warmth. They have no dormancy period, and their growth will stall or even reverse if temperatures drop below 65°F (18°C) for a prolonged period. |
| Pinguicula |
Mexican: 65–80°F Temperate:60–75°F |
Mexican: 50–65°F Temperate:35–50°F |
The temperature a Pinguicula experiences dictates its life cycle. Temperate species require a cold winter to form a dormant bud. Mexican species often enter a leaf-based dormancy during hot, dry summers to conserve water. |
| Utricularia |
Tropical: 70–85°F Temperate:40–80°F |
Varies by species and type. | Most tropical bladderworts are continuous growers, but some temperate aquatic species form a specialized bud called a turion to survive cold winters. |
Temperature Troubleshooting
| Symptom | Likely Cause | Scientific Explanation |
| No pitchers on Nepenthes | Night temps are too warm. | The plant lacks the specific thermal cue (the temperature drop) needed to trigger the metabolic processes required for pitcher formation. |
| No dew on Sundews | Temps are too high and/or humidity is too low. | High temperatures increase the rate of evaporation, causing the sticky mucilage to dry out faster than the plant can produce it. |
| Mold or rot | Cool temps and stagnant air. | Fungal spores thrive in cool, moist, oxygen-deprived environments. Using fans to increase airflow is critical to preventing these pathogens. |
| No dormancy response | Temperatures never dropped below 55°F. | The plant did not receive the crucial photoperiod and thermal cue it needs to begin its dormant cycle, putting it at risk of metabolic exhaustion. |
Adapting to Your Climate
- For Temperate Species: If you live in a cold climate (USDA Zones 6 and lower), you must bring your plants indoors for dormancy. An unheated garage, porch, or a refrigerator can provide the necessary temperatures. For moderate climates (USDA Zones 7–9), leaving your plants outdoors in a bog garden is ideal.
- For Tropical Species: In climates with cold winters, a controlled indoor setup with a heat mat and/or a grow tent is essential to maintain consistent warmth.
- For All Species: Monitor your grow space with a digital thermometer. This allows you to track day/night temperatures and make necessary adjustments to your setup.
