Although we’ve had a few rainy nights recently, most Toronto gardens are still very dry, which means that it’s not a good idea to apply fall fertilizers yet. Dig down 6-10 inches to see if you can feel some moisture and see the soil particles adhering together when you squeeze a handful.
By splitting annual fertilizer requirements into separate fall and spring applications, we can actually maximize plant uptake of important nutrients such as nitrogen. Potassium is another important element in fall fertilizing and can also help improve tree health.
However, when the soil is dry, roots will be unable to use the fertilizer salts and they may cause issues.
For more information, see the posting from OMAFRA here.