So far and from my understanding no minimal and maximal post required to earn merits and if you post something that is helpful to community you would see merits coming like flood to your profile,as a matter of fact a single post can possibly earn you up to 100 merits depending on creativity and useful you information could be. The thing is most of the topic created by newbie are the topics already created but just that they always reform it make it looks like another post or I will say there is always a particular methods mostly used by some newbie to earn merits and since lots of people knows giving out merits to similar post could be very hard.
That is the part I like most on this community there is no partiality on Merritt reward mostly once it has to do with quality post, you don't need to know any body or beg anyone to give you Merritt as much as your work or post deserve merit people you don't know will award you merrit, all you need is to create quality post that is informative and full of lessons and problem solving as regards to people demands in the forum.
To receive Merritt is not base in number of post created or reply everything lies in quality another aspects it does not matter weather your newbie or member what matter is the quality of the post and who ever that found it informative irrespective of level can merrit you without sentiment of looking at your level as newbies.