What is OASIS® Floral Foam?
An open-celled phenolic foam that readily absorbs water and is used as a base for flower arrangements.
Foliage green in color.
Holds over 40 times its weight in water.
For example: When a full brick of OASIS® Floral Foam is saturated, it will hold about 2 quarts (about 2 liters) of water.
Open Cell Structure
The cell structure of OASIS® Floral Foam resembles the biological make-up of plant stem cell structure.
OASIS® Floral Foam has wicking or capillary action, which draws water to the top of the foam. Due to its unique structure, it retains water in the cells.
A stem inserted 1" into a 4" piece of OASIS® Floral Foam is actually increasing the length of the stem by 3". When water is drawn up the stem, it is replaced by the cells beneath until the void is taken up by surplus water (outside the foam) at the bottom of the container. The capillary action continues, as long as there is a supply of water.
Consequently
OASIS® Floral Foam is not a substitute for water. Water lost by evaporation or consumed by flowers must be replaced. Add water frequently.
http://www.smithersoasis.com/res_techfacts.php