
Well the APS-6 units made a big difference in Winter Melon and Kabocha seed germination! The APS-6 cells are twice as deep as the APS-24 cells, and it looks like the bigger seeds need the extra depth.
Out of 24 cells (4 APS-6 units), I got 14 seeds to germinate (58%). However, 1 APS-6 unit did not germinate any seeds. It could have been that Algae got to this APS-6 unit before seeds could germinate, or it could have been that I somehow forgot to put any seeds in this unit. Discounting the seeds in this APS-6 unit, I got 14 out of 18 cells to germinate for a germination rate of 78%.
Next year, I will only use the APS-24 units for Cherry Tomato seeds and use the APS-6 units for the Winter Melon and pumpkin seeds.