Hell of a first post. I've been asking myself some of these questions for about a year. I'll make some initial comments before I retort to your questions.
I've always thought, "Wait, plants can't take in carbohydrate through the roots. They make carbohydrate in the leaves." Later, after reading more opinions and doing more research a couple reasons made sense for addition of a "sugar" under some conditions.
- Molasses often comes with micro-nutrient amounts of sulfur and some other elements that are taken up by the roots. So, the carb part of the molasses didn't seem to be the important part for the plant directly in the uptake regard.
- Also, I thought that maybe in a grow medium of soil or more likely outside the molasses mix could encourage helpful soil bacteria/fungus to live around the roots of the plant. Maybe bacteria break down the carbs and then the plant takes in whats left.
- Another thought is that maybe the addition of molasses to the nutrient delivery would change the tonicity of the immediate area around roots, and the change in tonicity triggers the roots to act differently, somehow increasing bud growth/size (whatever molasses promises).
- I hadn't thought of carb being broken down outside the root and then being shuttled in and/or osmotically brought in. But what breaks it down?
The general opinion is to administer the carbs during flowering to bulk up on the buds. Never seen any opinions saying any time other than the flowering portion of the plant's life.
As far as how all of this relates to the amount of sugar dissolved in the plant's fluid and tissue...good question. Plants make their own sugar in their leaves and the uptake in roots is controlled by controlled addition and subtraction of salt/water/nutrients/elements in order to create equilibria shift.
(rhode island. neither a road nor an island...discuss)