I have had the best results with Kellogs organic potting soil and Proven winners potting soil. They are fast draining, well aerated, ready to use mixes. Over watering is no fun. Get a bag of Jobe's organic rose and flower 3-5-3, Dr Earth organic rose and flower, or Espoma rose-tone. They will be so easy and effective if you follow the instructions. More is often less, that means less yield. They eat light, and only use nutrients sparingly. I have found rose fertilizers to give the most bud sites and stickiest/heaviest buds. Roses are also way more finicky than weed. So if it makes them bloom strong, then weed will love it.