Here, I have simply sown a mix of Mizuna and two varieties of Pak Choi into a seed tray. I like to sow my own mix of seeds rather than buy pre-mixed packets of salad seeds because I like to know what crops I am going to harvest.
The seedlings need watering regularly. In the hot weather, they grow quickly and have a tendency to bolt, so pick the sweet tender leaves as a cut-and-come-again crop.