Rhubarb is generally ready to harvest in the spring, typically from April or May, when the stalks reach about 10 inches (25 cm) in length. The harvest season lasts about eight to ten weeks, usually ending in late June or early July to allow the plant to recover and store energy for the next season. It's best to harvest by twisting and pulling the stalks from the base rather than cutting them, and to only take about one-third of the stalks at a time to protect the plant’s health. Rhubarb should not be harvested in its first year, and only lightly in the second year after planting to allow the plant to establish well. Leaves must be discarded as they are toxic. Harvest can continue lightly into the summer but is best stopped by July to avoid weakening the plant.