here is what I read about dirt craving, it is a lack of minerals in your dogs diet, and not so much in the food but the water.Wild canines can get their minerals from the water they drink, from creeks, running streams, if you were to dip a cup in a running creek you'd get dirt in it.You might not see it but if you drink it you'll feel it in your mouth(like sand)That is where for the most part they get minerals in small quantities BUT throughout the day it adds up to what they need.I did not get a whole lot of details but that is what I pulled out from this topic.If your dog eats dirt,raw state not the type you buy to plant and so on.I let my dogs dig in an area we have for them and if they eat the dirt , I don't care .You'll notice that they for the most part will not eat a mouth full simply bite into a hole or dig up and lick but unless they eat the rock ,that is when you want to stop them.Some rocks (lost of them) have minerals in them too.I got that info at the library i go often
I was reading up on the digestive tracks of Canines.The library has soo many books I would love to have!

How about it. Plant matter beyond the supermarket.

Dandelion Greens:
http://www.nutritiondata.com/facts-C00001-01c20dN.html

Grape leaves:
http://www.nutritiondata.com/facts-C00001-01c20n0.html

Fern fiddlehead:
http://www.nutritiondata.com/facts-C00001-01c20nH.html

Steven you are always on top, actually I saw some plants listed in the book that you can grow and dogs will actually eat it off the pot , but you couldn't use modern fertilizers.Did you read that somewhere? I am trying to recall that topic off my head..

Well, if one is so inclined, I think every lawn around here could be a carpet of pure dandelion if not kept in check.

Wild grape vines are also ubiquituous in untamed woodlands.

Free and abundant is good.

Now that I'm looking into it...Cattails! No kidding...gotta lot of those too.

http://www.econetwork.net/~wildmansteve/Plants.Folder/Cattails.html

Don't forget I am in the Desert...

Yeah...

http://www.rivenrock.com/

I'll let the dogs know they can eat the cactus we come accross at Red Rock