I love hearing from fellow concrete artists. Recently, Lee of Let's Talk Maples introduced me to the world of papercrete. Recycled paper (shredded and mixed with water to make a slurry), concrete and sand.
Located in the beautiful Ozarks of Missouri, Lee and Peggy operate a wholesale nursery and can be found at local farmers markets selling their plants and papercrete planters. See their vending schedule here. Also on this schedule you will be able to find Lee teaching seminars in making papercrete planters.
Need a recipe? A quick search for "papercrete" on the internet will result in many DIY home/shelter building sites with recipes yielding very large batches. I did find a couple sites with recipes you may want to try:
"Built From Trash" "Do It Yourself.com" "eHow.com" has good directions
I have not tried any of the recipes but as soon as the weather gets better I will give them a whirl. Just like hypertufa, everyone has their secret no-fail recipe. Please be respectful -- if you want Lee's recipe - sign up for a seminar.
Link to next seminars at Great Lakes Region of the American Hosta Society Hosta College March 11 to 12, 2011 in Piqua, OH Hosta College Class Course Listing