It is a non-sense question.
Fortunately, I known you were joking.
The question has been over repeatedly asked by merit-beggars.
It does not make sense because the true important factor is quality of threads/ topics, not quantity.
Let's start new topic only when you have something breaking, innovative, hot to raise. Then, merits (bunches of merits) might come to your topics, I strongly believe.
In contrast, no matter hundreds of topics you started, no merit will come to trash ones.
Fortunately, I known you were joking.
How many projects do I need to start to earn those. 
The question is nearly the same question like "How many threads I have to make to get merits and rank up?".The question has been over repeatedly asked by merit-beggars.
It does not make sense because the true important factor is quality of threads/ topics, not quantity.
Let's start new topic only when you have something breaking, innovative, hot to raise. Then, merits (bunches of merits) might come to your topics, I strongly believe.
In contrast, no matter hundreds of topics you started, no merit will come to trash ones.