can you please advise as to what type of fertilizer that I should be using for Spring? I live in the GTA.
Thank you for contacting the Toronto Master Gardeners.
Without knowing exactly what you would like to fertilize it is difficult to give you a specific answer. Are you interested in fertilizing your Lawn, Evergreens, Perennials, Fruiting Trees, or Roses? Each one of these items require diffierent concentrations of the macronutrients which are in fertilizers.
Fertilizers are always identified with 3 numbers known as the N-P-K ratio. The numbers indicate the percentage of nitrogen(N), phosphorous (P), and potassium (K) in the particular fertilizer mix. Nitrogen promotes new green growth which is important for plants that are mostly made up of foliage. This includes grass as well as evergreens and emerging perennials which is why you would use a fertilizer such as 27-0-0 or 29-2-4 inorder to green up your lawn, 30-10-10 for evergreens, 24-8-16 for perennials in the spring. Phosphorous promotes strong root growth as well as flower production. In the fall you do not want to promote leaf growth because that new growth would be damaged by the cold weather. Instead, in the fall you would fertilize your lawn with a fertilizer that has a high phosphorous number such as 5-10-5 to promote strong root growth. Finally, Potassium contributes to the overall health of the plant. Most fall fertilizers contain somewhere between 5-18% potassium. As with all chemicals make sure to read the label and follow instructions for dilution that is on the package.
Landscape Ontario has an excellent article on: How to Maintain a Healthy Lawn. They recommend a Late fall fertilization to increase fall and spring root growth followed by a late May early June fertilization.
I am including several links below from some of our earlier posts which give information on how to fertilize the various trees, shrubs and perennials you might have in your garden.