Sadez and I finally managed to fix the client/server syncronization problems, and now it works fine. The only downside (besides for so much wasted time on it) is that it takes slightly more bandwidth, since we had to send the global ID of each 3D object that is sent to the client. Not really a big deal tho.
Next thing on my todo list is to make the plants take resource from the soil, drop seeds, and die.
The problem is that we do not have yet any real data about how much the plants eat, so we are waiting for somene else to come up with that data. I am just implementing the system for the time being.
Another thing to be done, after the vegetation is over, is to make it so that you can cut the plants, even if they are not harvestible. This will be done so you can clear areas to build structures (or just cut off the weeds that are taking the nutrients from the soil).