Arie de Gelder blogs at Energiek2020:
"Crop colour and crop condition not always indicative"
Crop colour
As it turns out, the addition of led exposure in-between crops leads to more colour and higher production results than with Son-T. Interestingly, the combination diffused glass with hybrid lighting yields a significantly higher production than clear glass with hybrid lighting. The difference at this time is 1.7 kg/m2. At the moment we harvest heavy fruits (175 grams).
Crop colour, though, isn’t everything. It is about the activity of photosynthesis and this we don’t measure in terms of colour, but through CO2 uptake. That interpreting colour can even be misleading is confirmed when you look at the plants in the division with only led lighting. These crop always look very dark and colourful, but it's decidedly unwise to take this as proof of good growth.
Crop condition
In a previous blog (on changing weather) I have already mentioned that a crop shouldn’t be too generative and overburdened at the beginning of the lighting season. This was in fact subject to some debate early on. Is generative beneficial? In retrospect, we can surely say that this isn’t always the case. Plants that were very generative were also compromised by weaker crop development.
The generative condition and weak crop development combined with a slightly lower daily temperature cost us speed and production. At GreenQ Improvement Centre and Wageningen UR Greenhouse Horticulture we made an overview of recorded differences, which I’d invite you to consult for yourself. Of course, you can also wait for the final report of the trial.
Looking back on the lighting season I find that we are on track with the energy objectives and that production is above expectation. We have learned a lot and can look forward to another good year.
Source: Energiek2020