The farmer of Garampani area of Nainital District in the Central Indian Himalayas have developed specialized skills in cultivating off-season vegetable crops. The present study was conducted to identify the factors and circumstances leading to the switch over by farmers from subsistence to commercial crops, the process of change and adoption, economic impact of change, and its replicability factor. The study suggests that the existence of a primary market at Nainital was the main factor that induced the farmers from the proximate villages to adopt vegetable farming, and gradually this process of transformation diffused to other villages. Many socioeconomic and behavioural factors influenced the pace and extent of adoption. Markets developed almost autonomously with the increase in the volume of production. Currently, vegetables are grown in 63 per cent of the area under cultivation. It has increased the farmers income 2.72 times and direct employment 2.69 times. It has rectified, to a great extent, the unequal distribution of workloads among males and females and checked the rate of migration. However, vegetable growers of the Garampani area are facing many difficulties and need scientific consultation and assistance to resolve them. Experiences from the Garampani area suggest that the sustainability of mountain agriculture can be ensured by adopting off-season vegetable crops. However, this would need a scientific plan of action in order to maintain a balance among farming husbandry, and natural resources.