Generally it is seedling bulbs that make contractile roots (or use other mechanisms) to pull themselves down to some predefined correct depth whilst they mature. They expend considerable energy doing this, hence the now proven hypothesis that sowing seeds like crocus at a couple of inches deep gets them to flowering size a year earlier than if surface sown. If you plant a mature bulb at the wrong depth then it is pretty well stuck - no amount of grunting and groaning is going to get it down to its desired level. Seedling bulbs do this whether potted or in the ground, as long as they have the capability to start with. John John T Lonsdale PhD 407 Edgewood Drive, Exton, Pennsylvania 19341, USA Home: 610 594 9232 Cell: 484 678 9856 Fax: 801 327 1266 Visit "Edgewood" - The Lonsdale Garden at http://www.edgewoodgardens.net/ USDA Zone 6b