Seedlings that are grown outdoors and grown from seed are barerooted, which means that their roots are separated from the soil when they are to be moved to the planting site. To grow larger seedlings, smaller seedlings can be lifted and replanted in widely spaced rows, where they will have more space for growth. These are called transplants. Transplants also are barerooted. Barerooted seedlings usually are described by age class, using two numbers separated by a hyphen. The first number is the number of years the seedling has been in the bed where the seed was sown. For example, a 2-0 seedling is two years old. The second number is the number of years the seedling was in a transplant bed. For example, a 2-2 seedling was in the first bed for two years, then transplanted in to another bed where it remained for another two years. A 2-2 seedling is four years old. Barerooted seedlings are boxed; the number of seedlings in a box depends on the size of the seedlings. Red pine 2-0 seedlings are shipped from the State Nursery Program 1,000 seedlings to a box; 3-0 seedlings usually ship 500 to a box; 2-2 transplants usually ship 200 to a box.
Seedlings grown in pots or blocks are containerized; they are moved to the planting site in the soil in which they were grown and planted with the soil still attached to the roots.
Containerized seedlings usually are grown in a greenhouse. Seeds are sown in to cavities in large styrofoam blocks, often called styroblocks. Cavity size (volume) can be selected to accommodate different species and ages of seedlings. Common container sizes used for forest tree seedlings are listed in the table.
Seedlings are shipped either in the styroblock or extracted from the block and bundled. Extracted seedlings are wrapped in bundles of 20 and boxed, usually 600 seedlings or so to a box, and then frozen until they are shipped in the spring.