What percentage of plants are made up of water?

Plants contain a significant amount of water, with the exact amount varying depending on the species and stage of development. 

Most plants are made up of 70-90% water by weight on average. 

A fully hydrated healthy leaf, for example, can contain up to 92% water. 

However, the percentage of water in a plant can vary depending on its environment, stress factors, and other factors such as growth stage, water availability, air humidity, the plant's metabolic processes, transpiration rate, and soil water uptake. 

A plant that is experiencing water stress or drought will have less water than a well-watered plant.