when I post a new post on my blog is white, my ads appear only later.
AdSense/AdWords has a new policy where they will not bid on page impressions for page that have not been crawled. New content, by definition has not been crawled. When you visit the new page Adsense gets the requests, sees that the page is new and send the crawler "Medipartners-Google" to crawl and ad the page to the index. This takes time, a few minutes, up to a an hour possibley more in some cases. After being added to the index, the next request for the page is no longer new so an Ad may be shown.
On the homepage, ads appear normally until other pages are white,
There is a higher probability that your homepage is frequently viewed so it is normal that ads would appear, you other blog pages may not get sufficient traffic. Pages in the AdSense index have a certain life span after a few weeks they fall out of the index, so if your site has little traffic and the pages fall out of the index because they have not been viewed in a while then the scenario described above applies again. It is like your page is new.
Now what is described above is unlikely for a typical blog unless you have very little traffic. There may well be other issues affecting your site such as, [note: these may or may not apply to you but you should objectively evaluate your site to see if the do apply]:
1- Policy violations - these can cause ads to be shown intermittently and then if an addressed can cause your site from being banned
2- Little to no interest in your website or content from advertisers - typical for low traffic volumes, poor quality content sites, or sites that provide poor quality traffic, that is users that click on many ads but rarely convert once on the advertisers website.
3- Problem allowing AdSense crawler to acccess the pages - this goes to the situation described above - check your crawl report in your AdSense account
4- URLs that use parameters (like a session id), such that each user sees a unique URL for the same content - AdSense also sees a unique URL and think each request is for a new page
