I have never had fruit trees and would like to know how best to accomplish the above without doing harm to my trees.
This article should help: https://www.gardeningknowhow.com/garden-how-to/projects/espalier-instructions.htm
What plants are suitable beneath dwarf fruit trees in a small garden?
Ferns, hostas, caladiums, elephant ears, and cannas all make excellent understory plants.
How one learns and masters the technique/s of growing and raising dwarf fruit trees such as lemon, oranges, banana etc. ? I shall appreciate tips and references of books/CDs, etc. for the systematic study of this subject.
Here is some info to start with: https://www.gardeningknowhow.com/edible/fruits/fegen/dwarf-fruit-trees-a-planting-guide-for-fruit-trees-in-containers.htm
My dwarf fruit trees, which are planted in containers, are two years old. This summer, the leaves on the lime and orange are noticeably yellowing. Their growth is also very slow. Is this too much water? Not enough? Do they need fertilizer?
Here is some information about growing in containers:
https://www.gardeningknowhow.com/ornamental/trees/tgen/growing-trees-in-containers.htm
and about citrus trees:
https://www.gardeningknowhow.com/edible/fruits/lemons/how-to-grow-a-lemon-tree.htm
What is the best compost to repot dwarf fruit trees?
Any compost will do well for fruit trees, but mixing in some bone meal will help give support to flower, fruiting and root growth, which a repotted fruit tree will need.
I have a very small garden, with a reasonably sized patio. I would like to grow a few dwarf fruit trees. Can you suggest the minimum planter size which I would need?
This article should help: https://www.gardeningknowhow.com/ornamental/trees/tgen/growing-trees-in-containers.htm
I'm looking at growing dwarf fruit trees in my greenhouse. For almost all the fruit trees, citrus, nectarines, peaches, etc, they require a period of dormancy, correct? How do I find the dormancy rates/temps/etc. of these type of trees? For example, citrus tree soil temp must reach 35-45 F for 6 weeks before being able to start the next growing season (I have no idea if that's right, just a made up example). Or, are there any fruit trees that don't require dormancy?
All citrus and fruit trees go into dormancy. The dormant season tends to be during winter while their active growth season is the rest of the year.