I had this trouble too, build them only on good planets PQ10+, this will give you the benefit of more income from more people paying taxes, don't bother building them on small planets.
I was pretty much losing alot of games till I read the unofficial strategy guide, which you can get here Link

That are the reasons why I play as a populist (+20 morale +20 diplomacy) and as addition skill +30 economy and +20% morale or something like that....

I can't imagine playing anything different

If you don't build farms you don't get enough citizens to pay taxes. More citizens is good because it means more taxes, if and only if you pay close attention to the morale issues. I think most people underestimate how quickly they need to research the various xeno entertainment techs - also watch out for new types of entertainment where your old stadiums do not get auto-upgraded. Also, it is better to smooch a population of 20b with 20% taxes instead of a 10b planet with 40% taxes due to the morale penalty for high taxes.

Remember, if you get into popularity trouble and can't build enough low-tech entertainment do this: emphasize research in your empire to cut research times, then quickly research your entertainment tech. Once you got it, shift to social production emphasis in order to get those improvements built quickly. Then switch to a more balanced mix when you're over the crisis. What you shouldn't do is fill your planet's tiles up with countless low-tech entertainment buildings: that will never solve your real problem.

Finally, a planet with only 10b is way easier to invade than a planet with 22b citizens. One is the obvious reason that "big armies are good", the second and more subtle one is that the enemy needs high logistics to make a big fleet with billions of soldier. Not all opponents will have high logistics and then they'll have to take their total of, say, 10b soldier and invade over 2 or 3 separate attacks (much weaker than slamming the planet with all 10 at a time)

Build farms everywhere. It's best way to generate cash.

One farm on class 6 & 7 planets, two farms on class 8 & 9, three farms on class ten, four on class 11, five on class 12, seven on 13, eight on 14, ten on 15, and 12 on class 16+. Of course the best way would be to add these each time pop hits cap but on gigantic universe you probably don't want to micromanage that much.


You can make so much taxes from your population that trade is irrelevant... like a few % of total income (well, or less than one percent)..

Once you start getting populations on a single planet of 30+mil (happened to me a few times) managing the little buggers becomes a nightmare. As a stopgap solution i usually load a few million of them into transports and cart them off to wage war.

You guys forget about the stock markets that give +30 economy +10% approval and + 5% influence..

so what's better ?

a huge population, low tax, planets full of farms & approval building
or
a small population, high tax, planets with 1 or 2 farms max and tons of stock markets (around 6 stock markets do the job of one approval building, in late games..)


from my point of view small pop is better because farms add always the same cash but stock markets add %.. so it's just a matter of how much income your planets need to have for stock markets to make more $ than farms..
for example, if your planet make like 50bc/week : 3 stock markets can make more cash, approval & maybe even influence than 2 farms and an approval building..

I didn't install the latest patchs, I know farms give more pop now so it might be a little different but still, I don't think trying to have a huuge pop is good, either small or medium is best