Availability and capability of labor have become dominating factors affecting agriculture's productivity and sustainability. Agricultural mechanization can substitute for human and animal physical power and improve operational uniformity. Automation complements mechanization by implementing the capabilities of automatic perception, reasoning, communication, and task planning. Fixed automation is traditionally cost-effective for mass production of standard items. In addition, flexible automation responds to make-to-order batch processing. The appropriateness of each automation type depends on the situation at hand. Because of their vast memory and high calculation speed, computers are highly effective for rapid information processing. Incorporating state-of-the-art hardware and software, computers can generate status reports, provide decision support, gather sensor signals, and/or instruct machines to perform physical work. It is no surprise, therefore, that computerization is essential to the evolutionary process, from mechanization through fixed automation to flexible automation. Fundamentals of agricultural mechanization, automation, and computerization applied to greenhouse production are discussed. Recent research activities conducted at Rutgers Univ. are presented for illustrative purposes.