There are many different homemade fertilizers you can use for roses. Naming the best is hard because it depends on the type of roses, the type of soil you have, and what the climate is like in your location. Some examples of homemade fertilizers you might consider are used tea bags and eaves, eggshells, diluted human urine, coffee grounds, banana peels, apple cider vinegar, powdered milk, fish bones, and baking soda.