Read: the author's manuscript (in PDF file format).

For Better Strawberries, Grow Them Over Red Mulch

Strawberries grown on red plastic mulch are sweeter and more flavorful than conventionally grown berries, Agricultural Research Service scientists report.

The researchers grew strawberries on raised beds covered with red plastic mulch. By using a specially formulated red plastic, the scientists were able to keep the water-conservation benefits attributed to black plastic mulch, yet alter the amounts of far-red and red light reaching developing berries. That light, reflected from the red mulch on the soil surface, acted through the plants’ natural growth-regulating system to influence the size and flavor of developing berries.

The research was done by plant physiologists Michael J. Kasperbauer and John H. Loughrin at the ARS Coastal Plains Soil, Water, and Plant Research Laboratory, Florence, S.C., working with plant physiologist Shiow Y. Wang at the ARS Fruit Laboratory, Beltsville, Md.

Strawberries that ripened over the red--versus standard black--plastic mulch were larger and sweeter. They had higher sugar-to-organic-acid ratios and gave off higher concentrations of favorable aroma compounds.

Strawberries are a high-value specialty crop whose fruit size and flavor are important to both growers and consumers. Americans each eat about four pounds of the berries every year. Fat-free and low in calories, strawberries are full of vitamin C. They also furnish folate--a B vitamin--plus potassium and fiber. And they contain ellagic acid, a compound that fights cancer.

Kasperbauer, who pioneered the use of colored plastic mulches, has found that the higher amounts of certain growth-enhancing wavelengths of sunlight reflected by red plastic mulch improved many crops, including tomatoes and basil. Plastic mulches--most often black--are frequently used in raised-bed culture to conserve water, control weeds with less herbicide, keep fruit clean and produce ripe berries earlier in the season.

The research is scheduled for publication in the July issue of Photochemistry and Photobiology. The author's manuscript is now available on the web.

ARS is the chief scientific research agency of the U.S. Department of Agriculture.

Scientific contact: Michael J. Kasperbauer, ARS Coastal Plains Soil, Water, and Plant Research Laboratory, Florence, S.C., phone (843) 669-5203, ext. 109, fax (843) 669-6970, [email protected].