I do like the concept of requiring seeds as it adds depth and realism. But... is there a low-tech easy way to obtain seeds? Or, does obtaining seeds require research to unlock and certain other things that require considerable time/effort (like, perhaps, electricity)?

I would think obtaining seeds should be as easy as pulping a fruit or vegetable or otherwise sacrificing one crop plant such that you probably could not obtain food from it. But it should be low-tech. Humans have been obtaining seeds for farming/gardening since agriculture was first invented.