If your blog is indexed in the search engines, then your new and latest blog posts will eventually be indexed (sooner or later) by the search engines. However, if you wish to speed up this process (which you should), then there are three free methods which I would like to discuss:
1) Method-1: By using a Sitemap: Automatic Ping: You just have to add a sitemap generator plugin and whenever you post new content, search engines will be notified automatically. There are many sitemap generators plugin out there, but my favorite is Google XML Sitemaps v3 for qTranslate. This plugin automatically creates a sitemap file sitemap.xml which is modified every time you add a new post. To add this plugin, follow the installation instructions in the plugin page and install and activate the plugin. Then, go to Settings –> XML Sitemaps and create your sitemap. You have options for automatically notifying Google, Bing, Ask, and Yahoo (by adding app id). You can also manually add the sitemap file (stemap.xml) in your Google webmaster tools.
2) Method-2: By using Jetpack: Automatic Ping: You can use Jetpack to automatically ping the search engines. All you have to do is to install and activate the plugin. Then, go to: Jetpack –> Jetpack in your admin section of WordPress. Check that if “Enhanced Distribution” option is activated. By default it is activated.
3) Method-3: By using Pingomatic: Manual ping: Although, I wouldn’t recommend manual ping as it takes more time. However, if you are interested then, keep reading. There are many paid tools out there which you can use for manual pinging but my pick is Pingomatic. Go to the website and enter your Blog name, Blog homepage, RSS URL, and select the services which you want to ping to. You can ping to the following blog search engines: Weblogs, Blo.gs, Feed Burner, NewsGator, My Yahoo!, PubSub, Blogdigger, Weblogalot, News Is Free, Topic Exchange, Google Blog Search, Spinn3r, SkyGrid, Collecta, Superfeedr, RubHub, A2B, GeoLocation, BlogShares. Click on “Send Pings”.