Station capships around those planets to slow the growth, or build culture orbitals of your own to repel it with your own culture.

Raiding the culture centers is only a short term thing since they will be rebuilt pretty quickly.

Scout the planet, determine how many they have, and build more at yours. If you cant build more, put more on the planets that phase line to your vulnerable one, so their culture supports it.

Once you get a culture problem that endangers a planet, you need a lot of capital ships to repel it properly, so its not always an answer either, unless you are staging a large fleet there. Capital ships repel .3 (from memory) which isnt much use when the planet is throwing 30 at you.

I saved a planet of mine at 3% once, but only by building 5 to counter the enemies planets 4. Subsequently, the enemy lost its own planet to my culture

I usually deal with culture by calling them silly english conigits and flinging a cow at them. All from the top of my culture center of course.

The unity will claim you all, even those of you that smell of hamsters and elderberries.

How does culture work?

If a line of planets , with 'P' being my planets, have all logistic slots filled with culter stations  as shown below

P-P-P-P->ENEMY Planet with less culture production and less rear planet culture supporting - I am gueesing at this as I can't figure out how behind the front culture helps quantitatively - and still the planet has a culture alligience change of +0.07/sec and 100% allegience.

How can the enemy planet resist. how does culture really work?  How much is lost passing through friendly planets on the way to the enemy planet. 

It seems better to spend the resources on a fleet to kill the planet and only use sufficient culture to stop enemy culture.

Another question: if I have 4 planets all with direct phase lanes to an enemy planet is the culture attack stronger than that serial example above.

Third question.  Does the number of phase lanes that a culture producing planet have effect the spread rate detrimently.  An example, if a planet has 4 lanes, does each lane propagate 0.25 of the culture? Or does each lane carry the full rate.

thanks for reply.  I have been experimenting with culture and it only seems useful to stop enemy culture, very rarely has it been worthwhile, even Advent culture does not seem that overwhelming. I am playing against unfair AIs and started to wonder if they also get a culture bonus as well as the resource bonus.  That said culture did eventually destroy an ai that I trapped in a cul de sac of 4-5 planets from a desert culture broadcast centre, still an attack fleet would have cleaned them out sooner, but the fleets were all busy elsewhere but for some carriers used for periodic scouting raids.

I have another question.  Does phase lane length cause culture spread to attenuate down the lane such that a really long phase lane provides at the opponent planet only a negligible culture attack.

by culture bonus I meant additional culture generation, depending on the ai level, eg, a hard ai gets a culture generation rate of 1.5 x normal rate while an unfair ai gets double the normal culture generation.  Wondering about it as it seems almost impossible to push with culture late game. In a game I once scuttled every non-culture logistic structure on my 8 planets to build all culture and it did not overwhelm any planets - although it came close to taking down one before the ai responded. 

don't let the game get to culture wars!! i guess this only applies to small maps though..

Did the enemy culture at least retreat/get replaced by your own? In most cases, the Deliverance cannot flip a planet neutral in one shot - it can take multiple successive shots to cause the planet to revolt, depending on how far that planet is from the enemy capital and how strong enemy culture is there. It still causes the planet to generate your culture at 25.0/sec minus the rate of hostile culture being produced there (though I did get a case of 50.0/sec from an asteroid with only one phase lane).

On that note, your ships also have their damage output increased by 15% at a planet hit by a Deliverance Signal.