You need to make sure that the tank can clear a dose of ammonia to zero ammonia and zero nitrite in 24 hours. For a single betta, 1 ppm ammonia is enough for cycling.
Once you reach that stage you have several days to get fish. The bacteria don't starve overnight as used to be thought. If it'll be longer than 5 days, add another 1 ppm dose of ammonia.
Once you reach that stage you have several days to get fish. The bacteria don't starve overnight as used to be thought. If it'll be longer than 5 days, add another 1 ppm dose of ammonia.