The exposure time of plant growth lights varies depending on the plant type and growth stage. Generally speaking, 16 hours of exposure is recommended for the seedling/growing stage, 18 hours for the vegetative stage, and 12 hours for the flowering stage. The optimal light cycle ratio should be adjusted according to the specific needs of the plant.

During the flowering stage, the best time to use LED lights depends on the photoperiod requirements of the plant. Here are the key points:

1. Photoperiod requirements

Long-day plants: require 12-16 hours of light, such as lettuce and spinach.

Short-day plants: require 8-12 hours of light, such as chrysanthemums and cannabis.

Day-neutral plants: are insensitive to light length, such as tomatoes and cucumbers.

2. LED light usage time

Long-day plants: provide 14-16 hours of light per day to simulate long-day conditions.

Short-day plants: provide 8-12 hours of light per day to simulate short-day conditions.

Day-neutral plants: provide 12-14 hours of light per day to ensure sufficient light.

3. Light intensity and spectrum

Light intensity: The flowering stage usually requires a light intensity of 200-400 µmol/m²/s.

Spectrum: Red light (660 nm) promotes flowering, blue light (450 nm) maintains healthy growth, and the recommended red-blue ratio is between 3:1 and 5:1.

4. Practical operation suggestions

Timer: Use a timer to ensure accurate lighting time.

Monitoring and adjustment: Regularly monitor plant reactions and adjust lighting time and intensity as needed.

5. Notes

Dark period: Ensure that plants have enough dark time, especially short-day plants.

Temperature and humidity: LED lights will increase the ambient temperature, so pay attention to regulating temperature and humidity.

Conclusion

The best time to use LED lights during the flowering stage should be determined according to the photoperiod requirements of the plant, 14-16 hours for long-day plants, 8-12 hours for short-day plants, and 12-14 hours for day-neutral plants. At the same time, pay attention to the regulation of light intensity, spectrum ratio and environmental conditions.