They were first discovered and developed in the 1950's. The crystals can absorb up to 400 times their it's weight in deionized pure water. Cross-linked polyacrylamide is a rock-salt sized granular material which soaks up free water in the soil and swelling up to 1/4 to 1/2 inch in diameter with the ability of storing the water for the plants use. The roots of the plants grow through the gel-like hydrated crystals and absorb water as the plants need it.
Polyacrylamide crystals can be applied in various ways such as injection, gel-seeding, roto-tilling the crystals into the soil, manual seed spreader ,slurrys, and other creative application styles.
I have used polymers many times when doing new lawn and shrub installations and have had fantastic results from their use. The use of polymers by bedding plant growers has shown that ploymer use can help reduce the labor cost of watering bedding plants . The use of polymers as a nutrient rich jello for many various types of plants and shrubs not to forget lawn turf is a great way to help conserve water on lawn installations. There are companies out there today that can provide you with some of the best polymers in the U.S. One such company JRM Chemical out of Cleveland Ohio ( www.soilmoist.com ) provide a 99.7% Crossedlinked polyacrylamide that is a great performer in the landscape and garden. Polymers also have the ability to help reduce fertilizer and insecticide. and fungicide useage. The crystals when buried at a depth of 2-6" in the ground along side of the shrub or tree root ball or, sprinkled in the planting hole of bedding plants, add great survival rates for all newly installed plant, tree, shrub, and grasses.
Go out today and pickup a package of Cross-linked polymers crystals and experiment with some of your potted plant materials or, take the plunge and start incorporating the polymers with your installations of larger shrubs, ground covers, and turf areas. You will be on your way to saving money and doing your part to help conserve water.
* Some of this information was derived from the Summer 1990 edition of the Colorado Green magazine article " A Polymer for the drought years" by Daniel J. Wofford Jr. and Anthony J. Koski, Ph.D