Is there a way to specify an alternate tooltip? I don't want to modify the localization key for all instances of this property/descriptor, just this one instance of it.

Edit: Using any of these XML didn't work:

<Modifier  TargetProperty="PopulationGrowthMalus" Operation="Addition" Value="5" Path="../ClassPopulationStarSystem"/>

<Modifier TargetProperty="PopulationGrowthMalus" Operation="Addition" Value="8"    Path="ClassEmpire" Priority="1" /> />
<Modifier TargetProperty="PopulationGrowthMalus" Operation="Multiplication" Value="8"    Path="ClassEmpire" Priority="2" />/>    

It would show in the tooltip, but it didn't seem to have any effect. Instead, I ramped up the SystemGrowth property instead. It's not the same, but it has a similar effect.

You could try, instead of increasing the amount of Food, reducing the property PopulationGrowthUpkeep ?

I believe it would make your population grow faster without producing large amounts of Food - if I'm not mistaken, your population would simply need less food to grow!

From my experiments, that property *does* affect how much food your population eats, but it doesn't affect population growth directly. From what I can tell, it takes 300 food to trigger an addition of 1 population. If I have 1 Population, I'm only eating 1 food. If I change the PopulationGrowthUpkeep, I believe it affects how much food my population is consuming. So, when I have 2 population, I'll still only be eating 1 food. But it's my SystemGrowth that affects how much food I'm producing and "fills the bucket" of how much food before I hit 300 or the next trigger for a population bump. 

So, I think I need to find what property affects that "300/population trigger" and mod that :)

EDIT: I think I found the formula, but I'm not sure how to tell the game to apply it to my faction. I found this formula in the Registry.xml file:

<GrowthFormula>(300 * Property(Empire, @ClassEmpire, GameSpeedMultiplier) * $(Population))</GrowthFormula>

I tried adding it to the PopulationDefinitions.xml, but it didn't seem to affect anything.