Let me explain:
Basically, when you first get the animation core for farming, it says specifically that it will not replant, but you're sure you will find a way.
Later you do find a way. It's the water upgrade for a golem, which gains it intelligence. When give this upgrade, it will replant anything it harvests.
However, if you want it to automatically plant without the need of harvesting a plant which was there before, you will need a use core.
With the Golemancer's wand, click an inventory for holding plants to be planted, and then click a spot of ground on which you want it to be planted.
However, this is rather frivolous, as it would be quicker to plant them yourself, then get a smart farming golem to farm them.
I believe the exact same principles may be applied to lumber golems, but it would be nice if someone here could confirm that?[DOUBLEPOST=1381694532][/DOUBLEPOST]
pretty sure it was the order golem core that made harvesting golems replant, the thaumonomicon would tell you for sure though.
The order core allows for, I believe, in the farming golems, little more than another inventory to deposit into, to do basic two-way sorting of your harvested plants.