Influence of Planting Date on the Growth of Black Nightshade (Solanum Nigrum)

Black nightshade (Solanum nigrum L.) planted in the field at monthly intervals from March through October at Shafter, California, began to emerge in March when soil temperatures at a depth of 5 cm reached 17C. With the exception of August plantings, emergence remained constant for all plantings. Average weights of plants of May, June, and July plantings at 12 weeks were 60% greater than March and August plantings and 30% greater than April plantings. Plants began flowering 7 to 9 weeks after planting for the March through June plantings and 5 to 6 weeks after planting for the July through September plantings. Killing frosts in November prevented black nightshade planted in October from flowering. Black nightshade planted in April through July produced an average of 1000 berries/plant, which was 40 to 95% greater than those planted in March, August, and September. Seed production ranged from 20000 to 30000 seed/plant for the May through July plantings, and 600 to 8000 seed/plant for the March, April, August, and September plantings.