I really like what the Territorial Seed Company does in their paper catalog.
Each "category" of seeds has a block of advice with fields like
cultural advice
harvest
disease
pests
and "other" fields where relevant, like:
preparing the bed (for asparagus)
maintaining the bed (for asparagus)
transplants
to direct sow
blanching (for cauliflower)
spring culture
fall culture
That doesn't always fall cleanly into the category "genus".
All I can think of would be a set of fields for each genus, focusing on traits likely to be common accross the whole genus.
Or perhaps a themed series of articles with shared authoring, one article for each genus or category. Each database entry could have a link to the "parent article".
It could go into more verbose detail about methods of germination and breaking dormancy, or pruning, or propagating, or dealing with pests than most species currently have in their database entry.
Or verbose descriptions of climates where DS in spring is most suitable, or Fall direct sowing, or special handling of transplants.
Since the advice for a whole genus has to be general and full of exceptions, advice that might also vary with climate would still be appropriate.
And long articles full of generalizations seem more palatable when they aren't repeated hundreds or thosuands of times for each cultivar in a species.
And once a baseline is stated for the genus, a specific cultvar entry can say "more tolerant of X than most tulips" and still be meaningful to a novice.
