Real-time information sharing in the blockchain-based transaction system is a double-side sword for farmers. It benefits farmers by decreasing the demand uncertainty and harms farmers by delegating the monitor power to downstream buyers. A method to deal with the threat from real-time information sharing for small farmers is to improve the freshness of product by joining a cooperative. Using a newsvendor model, we focus on the farmer's choices to joining a cooperative and using blockchain technology and the farmer's optimal production decision considering different choices. Interestingly, we find that blockchain technology causes the critical ratio to increase and reveals the real market demand.