Hello,

I wouldn't spray the cucumbers with the water-baking soda solution, as this could cause phototoxicity to the leaves. Are you fertilizing? The plant looks "hungry". Container vegetables (and flowers) need regular fertilization because every time you water, you're leaching nutrients from the potting media. Find a fertilizer you like and apply it according to the recommendations on the label. You can also do a slow release pelleted form (apply it on top of the media) and combine it with a liquid feed (diluted in water).

The leaves appear to be the oldest ones? The new growth looks good. I would remove the oldest, most affected leaves. 

The pepper looks completely normal to me!