I made allot of bombs but gerald say sill he needs bombs so wonder if there are a npc I have
to talk to get type of bomb I need?

Pretty sure you need Grapeshot. I went from not being able to blow them up to being able to without 100% certainty of which bomb I had made inbetween, but pretty sure it's the grapeshot.

If you actually read your Nekker knowledges (character screen, attributes, knowledge tab), Geralt tells you what kind of bombs you need.

Thanks Solved

Why don't you read the gameguide? It says you need the beehive potion. Nevertheless, is there actually a beehive potion or is it really the one you mentioned?..

Edit:

The Gameguide is wrong actually it is the grapeshot bomb as Gruntex Mentioned

First, I didn't read the guide at all on my first playthrough because I like to play the game for myself the first playthrough.

Second, a quick google search shows they mistranslated and that beehive is supposed to be grapeshot, so I stand by what I posted earlier. ;p

Fun, that's what I meant.
Do you know the location of all the nests. Are they all east of the city? I am mising one and have already explored all the area up to the waterfall and the cave inside it.