<span class="link_user">@ElectricalBug</span>, Thank you for your comment and advise! I am aware that my pots are smaller than they should be, but the growing space in my home-made growbox is somewhat limited (40 cm x 40 cm per plant and the the height of the growbox is 120 cm). So I do not want to grow them more than 70 cm or so. Also I am using a vaporizer for buds, so my consumption is quite small. It means that buds from 4 small autos per year is more than enough for me :-)