I will weigh in on the growing media. We use ground pine pine bark over a 3/8" screen with the fines added back. This makes up approximately 70% of our mix. To this we add 25% composted chicken litter, with the remaining 5% being wood ash and sand. We use 15 pounds of 9 month Osmocote 18-6-12 and 1.5 pounds of Micro-Max(major and minor minerals) per yard. We mix in a 2 yard nursery blender. Trees will attain size to graft. We also use Nickel CBM, Pecan Kicker (5-0-10) and sulfur in foliar sprays. Iron and magnesium will be organically bound in the potting mix if phosphorus is too high. Also, pecans grow in flushes. If nutrients are not available at the time of need and growth stops most times it will not restart. If pecans are kept growing, half inch caliper and 60" in height can easily be attained.