These specifications are reviewed and revised annually. These specifications are guidelines for licensees. The smaller number represents the specifications on stock lifted prior to September 15. The larger number applies after this date. These seedlings are more expensive to grow and plant.
High densities produce small, poorly branched seedlings.
As nursery culture has developed, size expectations have increased. These seedlings also achieve large root masses quickly. As a seedling becomes larger and older, there are fewer cultural techniques that a nursery can use to control growth and prevent disease without reducing the vigour of the seedling. The size of seedlings can be expressed in terms other than height and root collar diameter. It is manipulated primarily by seedling spacing in the nursery.