Generate a full, in-depth guide on how to save seeds from your garden. The guide must be a detailed, step-by-step tutorial. It should include: 1. An explanation of open-pollinated vs. hybrid seeds and why it matters. 2. A detailed, plant-specific guide for saving seeds from three common vegetables (e.g., tomatoes, beans, peppers). 3. A guide to properly drying and storing your saved seeds for maximum viability. 4. A section on how to test the germination rate of old seeds. Please include a supportive disclaimer.