We determine aerosol growth rates in diameter ranges from below 10 to over 300 nm from long-term data with a novel automatic method. We show that aerosol growth rate in boreal forest increases with increasing particle diameter from 10 nm to cloud condensation nuclei (CCN) sizes and that the growth rate of sub-CCN particles is not suppressed by increasing condensation sink. Our findings suggest that aerosol growth to CCN sizes is a faster and less self-regulated process than previously estimated.