Apparently it transfers the moisture to the soil--used in Austrailia is what they claim
here is a link which shows various different studies by universities--
here is a link to one of the studies-
Here is wht they claim--
"After 9 years of commercial use by golf courses, nurseries, sod farms and top landscapers, Hydretain is now available to homeowners.
Hydretain is a revolutionary new natural chemistry that allows homeowners to water up to 50% less and maintain healthy, great looking plants and turf.
Hydretain is patented blend of liquid humectant and hygroscopic compounds that attract and hold moisture like tiny water magnets within soil. Hydretain manages available soil moisture, extending watering intervals of indoor and outdoor plants, flowers, vegetables, shrubs, trees and grasses by as much as 2 to 3 times. Each application reduces watering for up to 3 months