Greenhouse building to allow for passive auto-harvested crops. Purchasable on the farm and each plot can be loaded with seeds to automatically plant and harvest those seeds. In order to not be too powerful, starts with 1 row of crops (4 plots) and can be upgraded with a scaling gold cost similar to craftworks to obtain 1 more row per upgrade. If the gold scaling is right, it wouldn't be too strong of a building but would allow for a nice gold sink and more passive farming. 12 upgrades would be essentially equivalent to the tower 10 artifact that doubles crop growing speed (if you are at the 1T crop row purchased).
If there are concerns on the building being too AFK, could require each slot to use multiple seeds per crop planted to require purchasing seeds more often and/or reduced passive silver income, or require you to check in to "water" your crops so often to keep them growing.
