The best fertilizers for a flower garden are not necessarily super strength, but are formulated to promote overall plant growth and flowering. A balanced flowering plant fertilizer feeds the leaves, roots, and stems, as well as the flowers. Promoting only flowering, without taking care of the plants’ other needs, will result in abundant flowers on sickly plants. No one fertilizer can give a plant everything it needs, so combining several different methods to feed your flowering plants is a better choice.
Chemical Granular Fertilizers
Chemical granular fertilizers are easy to apply and come in a variety of formulations. The nutrients are fast acting, so they are excellent for quick results. When choosing a formulation for flowering plants, be sure that the middle number (phosphorous) is greater than or equal to the other two numbers on the label, and that the fertilizer contains minor elements such as magnesium, manganese and calcium. Fertilizers with 10-10-10 and 6-6-6 are popular general purpose fertilizers. A granular fertilizer specifically made for flowering plants with have a higher middle number, such a 5-10-5 or 15-30-15.
Chemical Liquid Fertilizers
Chemical liquid fertilizers can be applied directly to the soil around the plant, or as a foliar feed sprayed directly onto the plant. The most popular formulations for liquid fertilizers are 20-20-20 and 15-30-15. Specialized blooming plant formulations are available as well, which have very low first and third numbers, and very high middle numbers from 30 up to 50 or more. These “bloom busters” should be alternated with a more balanced fertilizer.
Compost and Rotted Manure
While compost and manure do not provide high amounts of nutrients, the nutrients they do provide are more available to the plant, as they are from an organic source. The use of compost and manure also promotes microbial activity in the soil, which encourages healthy roots. Healthy roots take up nutrients better and in larger amounts.
Fish Emulsion and Fish Meal
Fish emulsion is an excellent foliar feeder, because it is less likely to burn the plants. Fish emulsion and fish meal provide a readily available source of nitrogen, phosphorous, potassium as well as a good source of sulfur and trace elements.
Bone meal is made from crushed, coarsely ground bones and is high in phosphorous with a usual formulation of 4-12-0. It is commonly added to holes when planting flowering plants, since it does not move readily through the soil, and must be placed where it is easily available to the roots.
Organic Granular Fertilizers
The advantage of granular organic fertilizers is that they are easier to apply than compost and manure. The formulations are usually 1-1-1 or 2-2-2, but they have the advantage of being rich in available micronutrients.
Superphosphate (0-20-0) is a super-concentrated form of phosphorous fertilizer produced by treating phosphate rock with sulfuric acid. It is largely used in commercial operations of cut flowers, but can be used in the home garden in small amounts to encourage blooming.