Dear Diane, I have had bulbs in those pipes for quite a long time (more than 3 years now). -9°C is perfect for hardy bulbs, not too cold but not too warm. I've had Hyacinthus orientalis hybrids (Odysseus, Woodstock and Peter Suyvestant or Kronos is quite nice, 3 18/+ bulbs in one 30 cm long can go) or small Narcissus like Peeping Tom, Tete-a-Tete, Jack Snipe, Rip van Winkle, or dwarf tulips like T. clusiana and cultivars, T. Greigi-, Fosteriana-, Kaufmanniana-hybrids are all do very well so as Muscari armeniacum or other smaller ones (M. comosum id too big and leggy). Hope this helps. Bye, Jan Hungary