A greenhouse experiment finds water-sorbing polymers do not conserve water

To assess claims that water-sorbing polymers promote water conservation, a greenhouse experiment with container-grown marigolds was conducted to determine the effect of adding the polymers to soil mix. Plant growth and water retention in I- and 3-quart containers were not particularly affected, but in the 6-quart size, maximum water retention was significantly higher for the 4 lb/yd3 polymer treatment than for the other treatments, and the time from watering to wilt progressively increased from 6.1 to 7.4 days for the 0, 1, 2 and 4-lb/yd³ treatments. However, no water conservation occurred because evapotranspiration was not significantly affected by the polymer treatment.