It seems that whenever I sign up for a knitter's swap, I find my random internet surfing to coincidentally coincide with the swap's theme, and it's no different with this hand dyed yarn swap that I'm currently involved in.
I took a personal day to dye my swapee's yarn, using my own version of Kool Aid dying - a variation of how knitpicks and knitty go about doing it. And later this summer I plan to dye a wicked batch of sock yarn using Wilton's food dyes (instructions found here). As I was doing my skein today, being the environmentally concious person that I am, I was thinking what the process would be for more natural dying. (Anyone who has Polish grandparents like I do likely remembers colouring Easter eggs with onion peels!)
But then - (and here's where the random coincidence falls in!) - I get my newsletter email from Lionbrand about natural dying, using turmeric, yellow onion skins, grapes, and beets. And just for kicks, and also to not completely and simply endorse Lionbrand's website, dying yarn with black tea. I'm sure there's a link somewhere out there on how to dye with coffee, berries, and other naturals, I just can't find the links at the moment. But these shall hopefully keep you busy.
I've bookmarked all of these as things to do this summer while on vacation!
Oh, and just for kicks, knitty.com has a good article on hand painting yarn in a few methods - worth a gander if you haven't done so already!