I have read Vel's strat guide and it says you need +6 growth and extra food. I tried it last night in my game but nothing happened. Do you need a certain amount of extra food or will just one extra be enough? Also, should one try and boom as soon as one has the necessary parts, i.e. Dem and Planned?
For the Pop Boom, you need at least 2 surplus nutrient points for the population to increase.
Adding to b_c's post: In SMAC (not Alien Crossfire), you may only pop boom with:
-Demo
-Planned
-Childrens Creeche
-Eudaimonia
(you need to have 3 out of those 4)
since there is a bug that causes the Growth bonus from the GA not to be added to the rest of the bonuses.