WillC said:Over potting tends to deter growth because the plant puts most of its energy into filling the pot with roots at the expense of top growth. Plants grow best when kept moderately potbound.
Some plants grow best this way but many of them will get larger faster if they are in a bigger pot to start out with. Over potting is a well known and useful nursery technique for driving growth. Your first statement is untrue as a generalization, at least for the plants that I grow (including Dracaena). I usually try to match the size of the pot to the size of the plant for economic reasons, which is a different justification, and because I'm not in a great hurry to see them grow up.
The main issues here with a pot that's too big for the size of the plant are (1) it takes much longer to dry out, which could lead to problems relating to excess moisture if you don't adjust the watering interval; and (2) the roots are situated outside the zone at the bottom where water is concentrated after all the drops have left the bottom of the pot, meaning they are not in the best place to make use of the water until they grow into it.
WillC said:
Fertilizer is vastly over-rated. Plants use nutrients in minute quantities and cannot be forced into growing faster by adding more fertilizer. Light is the primary determinant of plant growth.
This is another untrue generalization. Adding fertilizer can lead to faster growth, and will do so in many cases, provided good uptake and active metabolism. If nutrients are not limiting to start with (for example, right after repotting), then the effect of fertilizer will be less obvious. It serves a role similar to the compost in the soil. But try the experiment yourself before reaching unfair conclusions. The reason people use fertilizer is because of exactly the opposite of Will's claim: it makes a difference in how fast and how well plants grow. Dosing is another matter; the indicated dose on the fertilizer package is usually several fold greater than you actually need for a useful response.
I can speak about the relative effect of fertilizer because I grew my plants for years with none at all. The plants did okay. Then I changed my routine and started adding low level nutrients to the water and they did better. I can tell you the difference caused by the nutrients because I have directly observed it. In any case I would encourage the curious to try out different ways of doing things and see what works best for themselves.