I found these folks while doing a search for Thorvin Kelp. They are located in Virginia so you folks out in that area of the States can order from them without having to pay to much for shipping. They sell in bulk on some items but do have smaller quantities of other items. Worth your time to peruse their catalog and see their offerings.
One thing I spotted was their McEnroe Growing Mixes that might be of interest to the container/tainer growers.
The Premium Lite Growing Mix:
McEnroe Premium Lite Growing Mix - A ready to use mix. This mix is designed to have many of the same lightweight characteristics as conventional soilless mixes without the addition of chemical fertilizers and wetting agents. Our trials here continue to shown excellent results. Contains compost, peat moss, perlite, vermiculite, rock phosphate, calcinated clay, gypsum and blood meal. The PH ranges from 6
.2 to 6
.8.
I will list the site URL here as well as in the compendium sticky. Ami
http://www.7springsfarm.com/catalog.html#Growing