I have some indoor plants that I didn't realize needed to be cooled in order to bloom. SInce it's too late to get cold air from outside, I'm trying to rig something to make it happen indoors (as cheaply as possible). The stem of the plant where it meets the soil is supposed to be kept around 4-5C (40F) for 4 weeks. I can't just put them in the fridge because they need light. So I've tried putting a frozen bottle of water in the soil next to the plant, and it works somewhat. The soil and stem are rarely cold enough. And I need to change the bottles twice a day for both plants. I've also tried putting metal knives in the soil pressed up against the stem, and putting the frozen bottle on the knives to nearly freeze them and keep the stem cold. It's not very effective though. I was wondering if some kind of solid metal taken out of the freezer would be more effective than frozen water. If anyone has any other ideas to make it work better or be less of a chore, I'd love to hear them! Thank you.