The best answer to that question is ‘as many as you can effectively cover’. Theoretically, the overall popularity and profitability of your blog should increase if you have more topics because this will help you attract a wider audience. However, promoting this kind of blog will be much harder and building up your personal brand around it – more challenging. To make the right choice, you’ll need to consider the pros and cons of both as well as your personal situation.
Think on the matter extremely carefully because choosing the right topic is a major factor for a blogger’s success. As there are over 30.6 million bloggers in the US alone, any advantage matters if you want to make money in this business.
Single-Topic Blog: Simple, Efficient, Direct
Any blog has to be consistent, therefore, maintaining one that only has a single topic will be hard. Unless you choose some extremely dynamic niche, finding new subjects for updates will be hard.
It might also be difficult to keep your readers interested because no matter how dedicated they are to the subject, they are sure to get bored with nothing but similar articles.
On the other hand, there are some topics that will fare perfectly well alone. For example, this will be the case if you are starting a recipes blog. Recipes are an extremely wide topic, even if you limit yourself to some specific niche within it, like vegan or dessert, or low-carb.
The readers that come to your blog are looking for specific kinds of recipes and as they have to cook regularly, they won’t lose interest. This kind of topic also offers great opportunities for sub-topics, like ingredient preparation and uses.
However, you also need to remember that the average word count of content that makes it to the first page of Google search results is 1,140-1,285. Will your single topic allows you to produce that kind of content often?
Multi-Topic Blog: Versatile, Interesting, Complicated
A multi-topic blog can generate more traffic, but to achieve this it will require a great deal more work. You will have to plan the SEO and design to work for several niches. However, establishing a readership will be a challenge still because you’ll either have to target an extremely small group of people with the same interests as you write about in your blog.
On the other hand, you can try appealing to different audiences at once. This will require a lot of resources and doesn’t guarantee results. Many people might find it annoying to subscribe to a blog that only posts about their favorite subject rarely.
Optimizing your website for multiple keywords from different niches is also nearly impossible. This means that trying to achieve good SEO might be the same.
Note that even the most popular and trusted blogs of today have a strong brand behind them and some general topic that unites their sub-topics. Even those took years to build up the reputation that serves them well now. As a beginner solo-blogger, your chances of achieving this aren’t high.
On the other hand, you can always invite different authors to guest post on your blog. This will help you attract a bit of their audience as well as provide you with fresh content.
Whether you choose a single or multi-topic blog, remember that the quality of content, as well as frequent and consistent updates, are the main deciding factors of your future success.