The Punjab Agriculture Department has advised farmers that summer vegetables can be cultivated from February to March as it is the best time for optimum produce. A spokesman for the department said on Saturday that temperatures ranging from 20 to 35 degree centigrade were conducive to summer vegetables. Vegetables should be cultivated on fertile soil and growers should use recommended seed varieties for maximum outputs. Manure should be spread on land one to two months before sowing, he added.