Hi all, I'm planning to grow some leafy greens indoor in front of a large north-facing window, but am not sure if I need extra lights. I live in a high rise apartment building, with every single one of the windows facing north; no balcony. However, I live on the 32nd floor with no obstruction in front, and the window area is quite large (the area where I plan to plant has a 3 meter wide window). I have a light meter and had been checking lux levels for 2 weeks. On a lightly overcast day, the level is approximately 5000-6000 lux after 8:30am and gradually rises to 9000-10000 lux around 11:00am; and keep the same intensity till 2 pm then decrease to 6000 lux around 4 pm.

I'd also read about " Daily Light Integral (DLI)", according to the data that I collected over the short 2 weeks interval; my planting area should be around 4.5 mol.m2/day on a cloudy day, and around 6 mol.m2/day on a clear day. If I'm only planning to grow collards, mustard greens, cabbage and some Asian vegetables like pok choi and tatsoi, do you think I need to install some artificial lights to supplement the window light? Thanks.