A general rule for roses is to "fertilize, fertilize and fertilize more." Tall roses with beautiful, large blooms usually require heavy fertilization. Although chemical fertilizers work, proper amounts can be difficult to estimate and over fertilization can be a problem. Organic fertilizers work slower than chemical fertilizers, but solve the problem of over fertilization. By applying frequent, liberal applications of homemade rose food, you will improve the size and quality of your rose bushes and blossoms.
In a quart-sized glass container or liquid measuring cup, combine 2 tbsp. powdered fish fertilizer, 1 tsp. kelp extract, 1 tbsp. Epsom salts, 2 tbsp. apple cider vinegar, 2 tbsp. molasses and 3 cups of water. Whisk the mixture to remove the lumps. Pour the mixture into a 2-gallon watering can and fill the can with water. The resulting fertilizer is enough for between two and four rose bushes. Water the roses after applying the fertilizer to force it to lower root levels.
Mushroom Manure Food
To make a larger batch of rose food, combine a bag of mushroom manure (about 28 L) with 1 cup of lime, 1 cup all-purpose organic plant food, 1 cup worm casings and 12 crushed egg shells. Add 2 inches of the mixture around your rose bushes and water in.
Fish & Bonemeal Food
If you need to have variable amounts of organic rose food, this recipe is easily converted to suit your quantity needs. Combine one part fish meal, one part alfalfa meal, one part greensand, one part gypsum and 1/2 part bone meal. Mix the ingredients thoroughly. Sprinkle the mixture around your roses before each watering and rub it into the soil before applying the water.