Update on using Schultz cactus potting mix for seed starting... A resounding success! My plants have done very well. I ended up planting Linda, Patio Choice Yellow (highly recommended), Burpee's Mighty Sweet and Sweet Tangerine, Sweet Sue, and Bush Early Girl. I'm waiting now to put them in the cold frame. The weather here is still cold and damp. I'll start another batch of plants using the same mix next week.