Only two more weeks and the days will get longer again on the Northern hemisphere, making it quite a challenge for growers these days to keep their crop up and running.
The team at the Delphy Improvement Centre is doing their best as well. They're currently conducting a light test in which the first bell peppers were harvested at the end of November. The plant load is now at around 28 fruits/m2. This is also the maximum plant load calculated for the darkest period with the 200 μmol/m2/s light intensity. The most difficult phase is only just beginning, according to BTO, and the current crop is a good start for the next cultivation phase.
During cultivation they've tried to regulate the amount of light according to the needs of the plant. "This way, we wanted to ensure that the crop did not become too heavy during the period that the supply of assimilates was greater than the demand, so that in the first few weeks light was shielded based on the sum of realized light. Starting in week 42 (4 weeks after planting) the number of exposure hours is slowly increased and from week 47 on we will use the lighting for the maximum 18 hours per day."
The challenge of the coming period is that the crop will not experience a dip in fruit production. A plan has therefore been drawn up for the number of fruits that are allowed per week, and fruit thinning is the solution. "The plan is to have a maximum of 3.5 fruits/m2 per week. As bell peppers don't always take every node, thinning is a precision job. But when we look back at the plant load, the plan worked well. We currently have fruit hanging in all stages, which should ensure that we get an even production through the winter."
No difference between departments
There are currently no differences between the two departments (full LED compared to a combination of LED and SON-T lighting). In half of each greenhouse there is extra far-red lighting. So far this provided slightly more stretching and less anthocyanin formation on the stem.
The fruits of the first and second nodes are currently harvested. The fruit weight of the main variety Mavera is around 220 grams and the fruits are very thick-walled. These fruits were harvested within 6 weeks after setting. "Two weeks before the first harvest the setting was somewhat lower, but this week we see this again."
Source: Kas als Energiebron