Hardening Off in the Forest Garden:

Seedlings grow accustomed to the conditions of the environment in which they are grown. Hardening off seedlings is eases seedlings into an environment with harsher conditions than those in the protected and controlled growing conditions of the nursery. 

In warmer climates, gradually removing shade and reducing watering prepares the seedlings for hot and dry conditions. In cooler climates, plants are often started indoors or in a greenhouse. Plants are then gradually brought outdoors to prepare them for fluctuating temperatures, direct sunlight, and wind gusts.

Forest Gardeners begin hardening off their nursery seedlings approximately one month before the rainy season. They begin by removing shade for one hour in the morning and one hour in the afternoon. Then after three or four days, they reduce shade by several more hours. After two to three weeks, the seedlings will tolerate full sunlight with minimal shock. Farmers also gradually extend the time between watering periods until seedlings are capable of surviving a week or more without water. Seedlings that are exposed to direct sunlight and minor water stress in the nurseries will be better prepared to survival after planting.