Collect rhododendron seeds in the fall once the seed pods turn brown and start to open. For germination, provide them with cool temperatures around 60-70°F and bright, indirect light. Use a well-draining, acidic soil mix. Lightly cover seeds with a thin layer of soil and keep them moist. Germination can take a few weeks, so patience is key. Have you tried starting with easier-to-propagate plants before?