Q: Is this a mod of excellent quality?
A: It seems pretty decent! I feel I have accomplished a lot in regards to usefulness and unique gameplay with relatively few additions to the game (most notably the advanced pyrolysis recipe). I may have gone a bit overboard with all the greenhouse variants, but they can be disabled, so it's fine.
Q: Using only water and electricity to grow wood seems a bit too simple! Why not make it a more involved process?
A: You could say it's a matter of preference, but I had many reasons. I could have made the production of wood require the extraction and cycling back of seeds, but I didn't feel that it was interesting enough, and I didn't like how the additional infrastructure for it would indirectly decrease the already low wood yield per area. I like to pretend that the extraction and recycling happens internally instead. I also think that the absence of this mechanic helps further differentiate the greenhouses from the Agricultural towers in Space Age. I could have made the production of wood require fertilizer, but that would obviously have to be produced from oil, which the greenhouses are supposed to be an alternative source of. And it felt even less right to use oil derived from wood, to provide fertilizer for the wood and somehow get a surplus from that. This also is not a thing in Factorio; none of the planted trees need this, so why should those grown in a greenhouse? Finally, I felt that the Mod Portal needed a "simple" greenhouse mod that actually is simple. Having no tiers of recipes means that no recipe has to be selected for the greenhouses, they just work immediately. I prefer that the greenhouses act as simple resource extractors like mining drills taking a fluid input, and I don't think they need to be more complicated than that.
Q: Greenhouse glass, just for the greenhouses! Were you perhaps annoyed by the idea of crafting greenhouses with iron plates, when their dome structure should obviously be fitted with transparent panes made of glass instead?
A: Yes!
Q: Will you make any further changes to the mod?
A: I may do a bit of tweaking still, aside from basic maintenance to assure its function. It seems unlikely that I will add anything else, because I want the mod to be simple.