Mini roses are no different than the large garden ones and require and like the same conditions as the large roses. I know they tell you that you can grow a mini rose in the house but usually the atmosphere is too dry for them. So what happens is the rose dries out quickly and often spider mites attack it and the rose goes downhill from there. If you want to keep the mini happy and healthy you have to make sure that it is misted daily so that it doesn't get dried out. Also repot it in a larger pot such as a 12 inch one. You can use any liquid plant food such as Schultz and use it at half the strength every two weeks when you water the rose. Roses like damp roots but doesn't like wet ones.