Yes Calin, just put more soil on top of the exposed little bulbs. Sown on or near the surface, bulbs first develop much higher in the soil than where they want to be in the end. They won't pull themselves down until the contractile roots shrink, mostly in the fall.
Calin the window sill experiment is earlier in this thread. Look for Lorn's posts with similar pics of the margarine tubs. Starts with post #290565, I believe:
http://garden.org/thread/view_...
Edited to change "Anthony" to "Calin".
