Optimal growing conditions: temperature and humidity
Multiple factors are important for healthy plant growth. The most important are light, temperature, humidity, and CO2. These factors influence each other and together determine how well a plant grows and flowers.
In this article, you will read how temperature and humidity affect plant growth and how to optimize them.
🌱 Why temperature is so important
Many processes in plants are based on chemical reactions. These reactions proceed faster at higher temperatures and slower at lower temperatures.
👉 A correct temperature is therefore essential for optimal growth and development.
☀️ Photosynthesis and temperature
Photosynthesis is the process by which plants convert light into energy. This process is highly dependent on temperature.
- Below 20°C, photosynthesis proceeds slower
- Around 25°C is the optimum
- Above 30°C, efficiency decreases
At excessively high temperatures, waste products are formed that disrupt the process, causing the plant to grow less efficiently.
👉 Read more about photosynthesis in plants.
🌬️ Plant respiration
Plants use oxygen to release energy from glucose. This process is called respiration and is essential for:
- Growth (formation of new cells)
- Maintenance (repair and preservation of tissue)
At higher temperatures, respiration increases. This can be detrimental, as more energy is then consumed for maintenance instead of growth.
⚖️ Balance between light and temperature
Light and temperature must be well coordinated. More light requires a higher temperature, so that the plant can optimally utilize the produced energy.
👉 This principle is also known as Plant Empowerment.
👉 Also read our article on light spectrum for plants.
💧 Humidity and evaporation
Humidity plays an important role in the plant's water balance. Through evaporation (transpiration), the plant transports water and nutrients.
- Too low humidity → too rapid evaporation
- Too high humidity → reduced nutrient uptake
In addition, evaporation helps the plant to cool itself.
🌡️ Effect of evaporation on temperature
When the temperature becomes too high, the plant will evaporate more to cool down. This costs energy and can inhibit growth.
👉 A good balance between light, temperature, and humidity is therefore essential.
📊 Optimal growing conditions
| Factor | Optimal value | Note |
|---|---|---|
| Temperature (growth) | 20–25°C | Slightly lower than flowering |
| Temperature (flowering) | 24–28°C | Slightly higher |
| Humidity | 50–70% | Depending on growth phase |
| PPFD | 30–50 µmol/m²/s (minimum) | More light = better growth |
💡 Practical tips
- Ensure a stable temperature in the grow room
- Adjust light intensity to temperature
- Monitor humidity with a hygrometer
- Prevent extreme fluctuations
✅ Conclusion
- Temperature affects all plant processes
- Photosynthesis works optimally around 25°C
- Humidity regulates evaporation and uptake
- Balance between light, temperature, and air is essential
- The right conditions ensure maximum growth and yield