Three studies were established to compare spring (S) vs. autumn (F) N fertilizer applications on apple tree performance. The studies used newly planted trees, 4-yr-old trees, and 8-yr-old trees, fertilized with either ammonium nitrate or urea at 2 weeks after harvest (F) or at bud break (S). In the first 3 years growth in a newly planted orchard, time of fertilizer did not significantly affect tree height or TCSA. In the first cropping year, F fertilized trees had the greatest flower cluster number and bloom density but similar % set and yield compared to S fertilized trees. F fertilized trees in mature orchards studies tended to be shorter and have smaller TCSA increment after 3 yrs. Treatments did not affect bloom density, % set or total yield although spring fertilized trees had a greater % drop. Although spur leaves of F fertilized trees had greater N content at bloom, shoot leaves typically had lower N and Mn, and higher P, K, and Ca at 90 days after bloom compared to S treatment trees.