See Inoculate your legumes for more information. However, there are some general comments that can be made. Powdered products such as fertilizers can usually be stored indefinitely if stored out of the sun and extreme temperatures. Liquid fertilizers have a shelf life of approximately 1-2 years if stored under the same conditions. In most cases, indication of a limited shelf can be found on the label.
Refrigeration can lengthen the shelf life of some of the more perishable products.
Some seeds such as cantaloupe, watermelon and cucumber seeds can last up to 5 years whereas seeds such as onions and sweet corn may store as little as 1 year. Germination usually declines with time so you may want to sow old seeds thickly. Seeds should be stored in a moisture-proof, sealed container. For more information on seeds, see Seed to Seed by Suzanne Ashworth. Generally speaking, rowcovers can either be heavy plastics or floating polypropylene fabrics.