Effect of harvest stage and nitrogen fertilization on the postharvest shelf life of black nightshade (Solanum nigrum L.) and collard (Brassica oleracea var. acephala L.)

Leafy vegetables play a crucial role in the human diet providing numerous nutrients and health benefiting compounds. like collard (Brassica oleracea var. acephala) black nightshade (Solanum nigrum l.) are commonly consumed leafy Kenya. However, their high perishability short shelf life (usually 1-2 days at ambient temperature) limits utilization resulting significant postharvest losses. This study assessed effect of harvest stage nitrogen fertilization on nightshade. Experiments were conducted Kabete field station, University Nairobi, using Field experimental layout was 4 x 3 factorial arrangement randomized complete block design with three replicates. Factors levels stage. Four (0, 30, 60 90 kg N/ha) applied 55.5, 111.1 166.6 where 0 N/ha control. Collard night shade harvested stages: weeks, 6 weeks 8 after transplanting. The kept room condition (20 ºC, 55% relative humidity). Data collection performed daily for quality related parameters which included color change, wilting index cumulative weight loss. Results show that there progressive deterioration storage time regardless level. Harvesting transplanting resulted longer (three days) (two when compared to harvesting or showed reduced hue angles over different stages. Black subjected had highest 33%. loss 29% recorded best angle 145°. Overall, longest both collard. These results low application fertilizer (30 (55.5 minimal effects good keeping quality. Key words: nightshade, Collard, Harvest Stage, Nitrogen nutrition, Shelf