Sounds like you have things well thought out, Arturo. You have good plans.
Lack of elongation of the stem is almost always caused by the plant wanting to grow faster than the nutrient source will allow. This usually means there aren't enough functioning roots to support normal growth. Most often, this can happen when a bulb is pretreated and it is is ready to grow. Normally, the bulb will grow roots first, while it prepares to send up a sprout. Then it sends up the sprout. But what if, for whatever reason, roots don't grow sufficiently? The bulb still continues to prepare for sprouting. If too much time elapses at the right temperature, the bulb will decided to sprout, regardless of the amount of roots it has. Rather than just growing very slowly, the growth pattern is very different. The sprout often looks almost like a mature plant in miniature, a short thick stem with lots of little leaves, and often flower buds.
Ultimately, the solution is time. It's a phenomenon with newly planted bulbs that corrects itself in the following growing season. But most importantly, if the stunted plant has flower buds, be sure to remove them as early as you are able. The plant is already struggling from lack of energy, and the flower buds are sapping what little energy there is, at the expense of normal growth of every other part of the plant.
Flowers and flower buds (and seed development later) are very strong energy sinks. In the case above, if you remove the flower bud(s) early enough in development - small enough to need a fingernail scissors to accomplish, you will often find that the remaining plant jumps into growth.
N.B. The other cause of lack of stem elongation is virus.
