SoilMoist is a commercial soil additive that boosts water retention of soil. It claims to reduce the need to water plants by reducing the infiltration of water, that is to say, water will drain through the top layer of soil less quickly, improving the residence time of water in the planting layer.
The product also claims to reduce compaction of soil.
SoilMoist has products differing in the size of the polymer (granular or fine) that benefit different applications. The granular version is an all around water retention aid that can be tilled or mixed into the top layer of soil. The fine version of the polymer is advertised for use in coating plant roots prior to transplantation to prevent transplant shock.
The product is advertised for agricultural or domestic use and claims to be environmentally friendly.
SoilMoist website: http://www.soilmoist.com/products/landscapers.php
Above is a picture of a flowerbed benefiting form SoilMoist application. The picture was chosen form the SoilMoist website because the guy on the right looks like Rambo.