Mesclun

Interesting point about Mesclun (Mixed Salad leaves) which generally does not do well with me. Local Gardening Club recommended the following tips:

Buy packets of seeds seperately and plant in large containers - lettuce/lambs lettuce & spinach together - Endive/Pak choi mustard & rocket together and Chard/beetroot together. Sow the 1st batch every 15 days. The 2nd every 21 days and the 3rd every 42 days to guarantee great pickings. Don't forget to add chive flowers/marigolds and nasturtiums to the salads for colour and taste.

I am trying this for the 1st time as normally I just don't get the seed to grow together, just lots of spindly leaves. Anyone else have experience of this growing methods