I used "comfrey tea" as the K component for boosting tomato crops and it worked well, and it sounds pretty much like your jauche stuff. That was really just for the fruit though, for the vegetative growth I relied on the fertility of the initial mix. My cucumbers were irrigated every morning but grown in the ground - the soil was basically always damp though. I know we were talking a lot about drainage, and that's definitely important, but the water demand was very high in the heat so if it seems like your pots are draining well, it might be worth giving them a drench every morning. Pots are quite unforgiving!