In my experience, no Sternbergia species (I grow six, if you count S. sicula as separate from S. lutea) needs lime to flower. Mine are all in a mildly acid soil mixture. However, I admit that S. candida has never flowered here, and I have three clones, one of which I've had for almsot ten years. I believe the main prerequisite for flowering in this genus is a warm position. They don't flower well in the open garden for me; I suppose the spring is wet for too long. However, I have seen them flowering well for years in Oregon gardens at slightly lower elevation, up against a south-facing wall. Therefore, I grow them all in a bulb frame and occasionally commit some S. lutea or S. sicula to the garden, where they make leaves but no flowers. In the frame, with very limited water from May through September, they bloom prodigiously. Jane McGary Northwestern Oregon, USA