Fig. 25: Time course of marketable yield (1. and 2. class tomatoes

Fig. 25: Time course of marketable yield (1. and 2. class tomatoes).

Letters indicate significant differences at the end of the experiment (HSD, p ≤ 0,05).

The 1. class yield amounted 9-13 kg/m2 (Fig. 26) and the 2. class yield 9-11 kg/m2 at the end of the harvest period (Fig. 27). The 1. class yield was not affected by the light source (“HPS” versus “Hybrid”). However, when Hybrid lights were mounted lower (“Hybrid”) a significantly higher 1. class yield was reached compared to when Hybrid lights were mounted higher (“Hybrid high”). This difference amounted about 30%. In contrast, the 2. class yield was independent of the height of the lights. However, the 2. class yield was significantly higher when plants received HPS lights compared to Hybrid lights (Fig. 27).

Also, the marketable yield of the whole chamber was measured (Fig. 28). A higher marketable yield was reached with “HPS” (5,5 kg/plant) and “Hybrid” (5,7 kg/plant) compared to “Hybrid high” (4,8 kg/plant).