You should write in the vicinity of 800+ words of new content for the MAIN articles on your site, and consider them your anchor content. A few other articles can be 'satellite' artcles that are half the length, and everything else can be a little as 100 word posts with 'dwell bait' (an image or embedded video, etc), i.e., elements that can keep viewers on the page longer. Whatever, the point is not every post has to have long blocks of text on it.