culturing C. elegans on K12 E. coli

Has anyone tried to culture worms on NGM + k12, rather than NGM + OP50?
What precautions do I need to know?
Is there anything different I should do?

HT115 is K-12, isn’t it? Almost every worm lab uses this as food in fRNAi experiments. I have also fed worms XL1Blue, which is K-12, I believe. Labs that have studied bacterial diet have used additional K-12 strains as food, I am sure. Shtonda and Avery 2006 is one example of an paper that might be informative, although it might not directly address your question.

I am not sure what you mean by precautions. K-12 can save you some paperwork, from a biosafety standpoint. (See the NIH Guidelines, Section III-F-6 and Appendix C-II.)