I grow many of my water sensitive bulbs in a pure grit (pumice and Turface). My succulents especially the ones with fleshy roots get a very porous mix, 75% grit and 25% metromix 560 coir. The fibrous rooted ones are 50% and 50%. I have C. spiralis which is in my 100% grit mix. Any thoughts on watering? PBS tips are almost bone dry in summer and very infrequent watering in winter. What about spring and fall? I am not good at understanding 'almost and very infrequent'. Any thoughts for us east coast, lower light, damp and humid and sometimes cool growers? For some back up information in the winter I grow under lights in my basement. During the summer, water friendly bulbs are outside. Water sensitive bulbs are in my small greenhouse. Dormant bulbs spend the winter in the greenhouse with low a temp. of +/- 45 deg F. Ken P Old Bridge, NJ Zone 6b