1. Training Young Cherries Janet Caprile Farm Advisor Contra Costa & Alameda Counties Small Farm WG April 7, 2006 UCD

2. Training Young Cherries High density High density –Smaller trees Easier, cheaper to pick Easier, cheaper to pick Lower liability without ladders Lower liability without ladders –Earlier production –Higher initial tree & training costs

3. Training Young Cherries Vigor Reducing Tools Vigor Reducing Tools 1.Rootstocks 2.Plant Growth Regulators 3.Summer Pruning 4.Limb positioning 5.Deficit Irrigation

4. The Tools: Rootstocks Standard: Mahaleb, Mazzard, Colt Standard: Mahaleb, Mazzard, Colt –Vigorous, 15-30’, 6-8 years to bearing Dwarfing: Giesla selections Dwarfing: Giesla selections –Precocious: fruit in 3-4 years –Smaller Giesla 6 – 10% smaller Giesla 6 – 10% smaller Giesla 12 – 25% smaller Giesla 12 – 25% smaller Giesla 5 – 60% smaller Giesla 5 – 60% smaller –Potential to overcrop -> smaller fruit –May need support –Limited CA experience

5. The Tools: Promalin (PGR) For the 1 st & 2 nd dormant seasons For the 1 st & 2 nd dormant seasons Increase branching on 1 year old shoots Increase branching on 1 year old shoots –More branches = smaller, lower vigor branches Narrow application window Narrow application window –Terminal bud swell to 1/8” leaf tissue Variable results Variable results –Prolonged bud break –Phytotoxicity

6. The Tools: Summer Pruning Why Why –To reduce vigor –Increase branching –Reduce size –Advance tree training When When –May to June How How –Head 24-30” current season shoots back by 1/3 –Thin out vigorous branches competing with scaffolds –Keep the smaller, weaker wood

7. The Tools: Limb Positioning Horizontal branches are less vigorous, more fruitful Horizontal branches are less vigorous, more fruitful In summer, before bud initiation In summer, before bud initiation Bend vigorous scaffolds to 0-45 degrees Bend vigorous scaffolds to 0-45 degrees Tie in place Tie in place –Trellis –Strings & hop clips –To the next tree Retie or drought stress to avoid swoopy growth Retie or drought stress to avoid swoopy growth

8. The Tools: Deficit Irrigation Goal: Goal: –stop growth –set terminal bud Mid summer Mid summer 50-60% ET 50-60% ET Watch out for Watch out for –Yellowing, defoliation –Sunburn Full irrigation mid Aug-mid Sept Full irrigation mid Aug-mid Sept –prevents doubles, sutures, spurs

9. Training Young Cherries Vigor Reducing Tools Vigor Reducing Tools 1.Rootstocks 2.Plant Growth Regulators 3.Summer Pruning 4.Limb positioning 5.Deficit Irrigation Use a combination Use a combination