DECREASING THE NO3 AND INCREASING THE VITAMIN-C CONTENTS IN SPINACH BY A NITROGEN DEPRIVATION METHOD

Excessive use of nitrogen fertilizers is known to increase the NO3 and reduce the vitamin C contents in fruits and vegetables. We investigat ed the concentration of these compounds in spinach leaves when plants were transferred to nitrogen-free media prior to their harvest. It was noted that a pre-harvest transfer of spinach to N-free media reduces the NO3 and increases the vitamin C content of the leaves by a substan tial amount in a 2-3 day period. It is suggested that this technique m ay be suited to produce spinach or other leafy vegetables with low NO3 and high vitamin C contents under commercial hydroponic conditions.