About sweet cherries
Tart cherries thrive in zones 4 to 6, sweet cherries in zones 5 to 7. Tart cherries are self-fertile, while sweet cherries need a compatible variety for cross-pollination. Choose sweet cherry varieties that are especially adapted to your climate and resistant to the major diseases in your area. Standard-size trees start bearing in about their fourth year, dwarf trees in about their third year. One mature, standard-size tart or sweet cherry tree will produce 30 to 50 quarts of cherries each year; a dwarf tree, about 10 to 15 quarts.
Choosing a site to grow sweet cherries
Choose a sunny site with good air circulation and deep, well-drained soil. Avoid low areas or places surrounded by buildings or shade trees, where cold air settles.
Plant cherry trees in early spring. Set bare-root trees atop a small mound of soil in the center of the planting hole, and spread the roots down and away without unduly bending them. Identify original planting depth by finding color change from dark to light as you move down the trunk towards the roots. If the tree is grafted, position the inside of the curve of the graft union away from the afternoon sun.
For container-grown trees, remove the plant from its pot and eliminate circling roots by laying the root ball on its side and cutting through the roots with shears. Don't cover the top of the root-ball with backfill because it could prevent water from entering.
Space sweet cherries on standard rootstocks 35 to 40 feet apart; dwarfs, 5 to 10 feet apart. Space tart cherries on standard root stocks 20 to 25 feet apart; dwarfs, 8 to 10 feet apart. Set trees on standard rootstocks with the graft union a few inches below the soil level. Set trees on Colt dwarfing rootstock with the graft union several inches above the soil level.
Train dwarf tart cherry trees to a central leader. Train semi-dwarf or standard-size cherry trees to a modified leader. Prune trees every year in late winter to encourage the growth of new fruiting wood. Don't prune in the fall. Fertilize each spring until trees start to bear, then fertilize only after harvest each season. Cherries are susceptible to a number of different disease and insect pests, depending on region. Contact your cooperative extension office for information on managing pests in your area.
How to harvest sweet cherries
The sugar content of cherries rises dramatically in the last few days of ripening, so wait until they turn fully red, black, or yellow (depending on the variety) before harvesting. Harvest as the cherries ripen over the course of about a week. Pick the cherries with the stems attached, being careful not to tear off the fruit spur that will produce fruit year after year.