Yes having fresh content on your website can help you boost your search engine rankings.
When you have fresh content added to your website often Google Search and other search engines will crawl your website more often and another added benefit is that the more content you have indexed in Google and other search engines the more traffic you're likely to get to your website from those search engines when someone does a search on Google, Yahoo, Bing and other search engines.
Having fresh content will also keep current visitors coming back to your website.
Remember that a website is never finished and requires adding content constantly over many years to keep the website ranking in search engines and getting traffic.
Google Search does use content freshness as a ranking factor so it's a good idea to keep adding fresh content to your website a minimum of once per week but the more often you do add content the better.
But do make sure it's quality content because the better quality content you write on your blog or website the better it's likely to rank in Google and other search engines.