The best time to plant trees is in spring, soon after frost leaves the ground. At this time the soil is moist, the climate is somewhat mild, and normally there is ample rainfall. If you must plant in late spring or early summer, use container-grown seedlings, because they tend to experience less transplant shock than direct-sowed seedlings. Fall planting usually is less successful because root growth is slowing, frost heaving may occur over the winter (especially in clay or wet soils), and growth regulators in the tree may become imbalanced, leading to top dieback.
Take good care of seedlings before planting! Ask the nursery to ship them using the swiftest transportation method available. If you transport the seedlings yourself, protect them from wind and sun during transit. Inspect the seedlings upon arrival. They should be dormant (that is, the buds and roots should not have begun to break, and should have no mold, be moist and flexible, and show no significant browning (especially on conifer needles). If you cannot plant the seedlings immediately, store them in their original container at a temperature of 35° F to 45° F.
If you need to postpone planting bareroot seedlings for more than three to five days, remove them from the container and heel them into a trench (Figure 4-3). Store seedlings in this manner only so long as they remain dormant. Once they begin to grow, take extreme care to prevent their roots from drying out when you dig them up, transport them to the planting site, and replant them.
While planting, keep the seedling roots moist, but do not immerse them in water for more than 30 minutes, as this can lead to root damage and loss of beneficial microorganisms. Exposing tree roots to hot sunlight and drying winds for three to five minutes may be fatal.
Plant trees by hand or machine following these rules:
Figure 4-3. Heel-in bareroot seedlings for temporary storage. 1) In a cool, shady location, dig a V-shaped trench that is deep enough so the earth will cover the entire root system and part of the lower stem. (2) Remove the seedlings from their container and spread them along the slop- ing side of the trench in two or three layers. (3) Pack soil around the roots. (4) Water as necessary to keep roots moist.