My first help.

Yes. You should build farms, it increased every output of your planets.

 

But, I don't know the optimal nomber of farms to build. I put 1 for every 5 title of the planet.

On any base planet with zero bonuses and is say class 10. I would put two farms+one hospital all touching if possible. Then add one factory or two. Fill the rest with banks if you have that tech. You may also need one happiness building. Happiness techs are in the same tech to upgrades on banks so its worth it to go down this tech line. 

Lars advice is very good.  On almost every new planet my build order is: Hive(if i have it), factory,hospital,farm,farm. then fill with my choice of specialized blgs.  Typically i put it on Mfg focus until build out is done. As population grows i may need to swap in a moral booster, and as my pop cap is reached I will swap in another farm till i reach about a 40/60% ratio of farms to specialty bldgs. 

I've experimented with this, and I think farms are BY FAR the most important improvement, because population directly equals Raw Production (times any bonuses). My standard build-out is like this: 1. One factory (and only one) next to the capitol or on a manufacturing bonus square if there is one. 2. Faction building (e.g., Missionary Center for benevolent civs). 3. Then spam farms like crazy, ideally having a hospital surrounded by farms. And concentrate on farm and growth upgrades in the colonization tech tree. 4. If I have special bonus tiles, I might build another factory, or a market, or an entertainment center, or a research center. But the large majority of my planets have just one factory and no research center. You don't need those. 5. You'll also want to devote an occasional tile to one-shot buildings like the Hyperion Shrinker, Technological Capitol, etc. I routinely have planets with populations around 100.

Nah. You guys are doing it wrong. Since Birthing Subsidies was nerfed, it is pointless to build the Hospitals unless you have space to spare. Even with the project, you are looking at about a .3 growth max. Instead, build a Biomass Resequencer. It has the same adjacency bonuses as the Hospital, but it increases your food production.

 

And yes, if you want more money, build a planet with nothing but wealth improvements and farms.

OK i am confused, In my current 1.4.1 with pop proj & hosp, i can grow at .5/turn.

True but if you are trying to max a specialized planet, the best layout in theory is a 50/50 split of farms and markets

Thanks

there is a maximum level or the population of a planet grows "infinite"? Each planet has a maximum population? If you like you do not understand this level?

I think the first thing to do is to grow the population to increase the level of money. Right?

 

The population growth cap of a planet is equal to its food production. However, the population cap is technically unlimited since you can have more population than food by moving population around via transports and colony ships.

 

Yes, growing the population will directly help to increase Wealth even without wealth improvements.

Thanks. It will also increase the production of a single factory guess.