Just today I "found" a very nice website for information on food storage, survival and similar topics. Angela has several posts about a spring "opportunity" most people think of as a nuisance: dandelions.
This information is a great example of "supplementing" one's mobile food supply or home food resources. Learn to work with and enjoy wild edibles like this now, and you are more prepared for gathering wild foods in an emergency situation.
From what I've seen of her site, I give her very high marks not only for knowledge but also for effectively teaching what she knows. I'll provide the link to Angela's blog post that summarizes several of her other posts on dandelions. She has great, clear photos of things such as how to peel the roots for cooking and eating.