Spring, Year 2: Rootstock liners are planted in the field in long rows. Plants are usually spaced 30 to 35 cm apart in the row and about 100 cm between rows. During the growing season the nursery rows will be inspected periodically, and multiple shoots and any side branches are removed to ensure that only one straight stem per liner grows.
Late Summer, Year 2: Bud sticks are collected from good true-to-name cultivar trees that are free of diseases and viruses. In some instances, these trees are specifically grown just as budwood sources. The rootstock liners are then bud grafted either by chip budding or T-budding. The buds are inserted approximately 15 cm above the soil line. Occasionally in apples and pears, buds may be inserted higher to have more of the rootstock shank exposed. There is an increase in size control of approximately 10% for each inch above the soil line the rootstock shank is exposed.
Spring, Year 3: The rootstock liner is cut just above where the bud was inserted while the trees are still dormant. A single shoot is grown from the bud.
Summer, Year 3: Many nurseries will regularly walk the newly emerging buds to ensure that only the desired bud is growing and remove any root suckers that may develop. Nurseries may attempt to induce greater branching by either hand pinching the growing shoot or through the application of plant growth regulators.
Fall, Year 3: The finished trees are dug from the nursery graded by diameter and bundled together. The leaves may be allowed to drop naturally, or they may be induced to drop earlier through chemical treatment. The trees are stored in a cold storage with their roots kept moist. In areas that have moderate fall climate, the trees are sometimes sold at this time to the grower for fall planting. Trees planted in the fall are dormant. The advantage of fall planting is that the roots have a chance to establish themselves and produce some growth prior to leaf emergence the following spring.
Spring, Year 4: Finished trees are sold to the commercial fruit grower.
Robert Crassweller, Penn State University