From the best cannabis book ever - "Marijuana Botany" by Robert Connell Clarke........
GENOTYPE - combination of genes present on chromosones in the nucleus of each cell, which through environmental influences determines the outwardly observable phenotype.
PHENOTYPE - outwardly measurable characteristics of an organism determined by the interaction of the individual genotype AND the environment.
Therefore, my interpretation is that phenotype is the environmental expression of a plants genotype.
So yes, phenotype expresses itself after the seed breaks the soil and "reacts" to its environment.
Hope this helps, Organoman.