To add to what Leo says here, it is important to consider elevation as well. This affects nighttime temps especially and accounting for this can make all the difference culturally. Most of our favorite plants do not grow at sea level or high in the mountains but in places in between. Plants that grow where nights are cool (about 55F) cannot properly process the food they have gathered via light during the day if nights are too warm. Their metabolism is interrupted and this can be fatal. Understanding the importance of nighttime temps, which is greater than daytime temps, is critical in growing certain bulbs. The worsleyas, as I understand their habitat, do grow on exposed inselbergs but these receive appreciable cloud cover at least for part of the year. They are tropical but elevation (several thousand feet I believe) plays a vital role. Probably a majority of terrestrial plants, including bulbs, grow in soils that are predominantly mineral-based. This can be difficult to replicate in pots and we are tempted to use a lot of organic material out of habit. It is true that many of these plants can thrive in such an organic mix (witness commercial cactus culture) but for the hobbyist it is probably better to grow in a long-lived "mineral" compost that is mostly pumice and sand and just a little organic matter to add body and hold things together structurally. In this way there is little to break down and many plants can be kept happy for years in the same pot and mix. Dylan * *