Many customers ask themselves which dim value they should set the light to depending on the phase.
Short answer:
If you grow cannabis and use one of our lights on the recommended area with a distance of 25-35 cm, the following recommendations apply:
- Seedlings and cuttings: 10-20% or 100-200 µmol/m²
- Young plants: 20-30% or 200-300 µmol/m²
- Vegetative phase: 30-60% or 300-600 µmol/m²
- Flowering phase: 50-100% or 500-1000 µmol/m²
Long answer:
In practice, the ideal dimming level or light intensity depends on many factors. Beginners in particular should start with a lower intensity to familiarise themselves with the plant and its interactions with the environment. At high intensity, metabolic processes take place much faster, so it is important to keep all parameters in the grow room under control.
These factors influence which dimming level is appropriate:
- Cultivar / Genetics: Of course, microgreens and leafy vegetables have completely different requirements than heavy consumers such as tomatoes, strawberries or cannabis. But the individual strains of a genus can also vary greatly in some cases.
- Cultivation area and distance: The dimming level affects the PPFD depending on the surface area (size, presence and efficiency of reflective walls, etc.) and distance.
- Environmental conditions: Temperature and relative humidity act as a so-called VPD on the plant. This metric also influences the plant's ability to photosynthesise. If a plant transpires too much, the stomata close and photosynthesis is reduced to a minimum. In such a situation, it would therefore be advisable to turn down the lighting, set a higher distance, etc. to reduce temperatures and evaporation.
- Nutrient supply and CO2: In order to utilise high values effectively in the lighting, the nutrient supply and CO2 levels must also be adjusted.
