Fertilizer applied in the fall strengthens the roots of your plants and grass, giving them a rich soil in which to grow and thrive next spring. Lawns and landscaping don’t go away as soon as the summer is over. In the fall time, many plants come out of heat-induced dormancy in the time between temperature extremes. This means your grass, flowers, trees and bushes still need help before they slow down for the winter, and a shot of nutrients just before the cold sets in can make a huge difference when the weather gets warm.
But how late is too late?
The Latest You Should Fertilize Your Lawn
The final application of fertilizer on your lawn should come at the end of October or in early November. This shouldn’t be the only time you put down some nutrients after the summer is over. Ideally, you’ll want to give your lawn a dose of fertilizer in September because the grass is recovering from the dry weather. It may have gone into dormancy due to the heat and a lack of water, so you’ll want to give your lawn a shot of nitrogen to push blade growth.
Not all fertilizers are alike, though. You’ll notice three numbers on the bags at your local home and garden store; these symbolize how much nitrogen, phosphorous, and potash (in that order) are in the formula. The formula you use in September should be different from your choice for the last use of fertilizer of the year:
- In September, a boost of nitrogen will help the grass come out of dormancy and get growing. A formula with a balance of 20-8-8 is the best choice.
- For the final fertilizing of the season in October or November, you’ll want the grass roots to strengthen and grow before dormancy. This can be helped by a mixture with a higher amount of phosphorous, so choose a formula with a balance of 13-25-12.
The Latest You Should Fertilize Your Flowers, Shrubs, And Trees
For your garden, fertilize the plants at the same time as the lawn. Even though the perennials are beginning to wilt and fade, they can still benefit from fertilizer cultivated into the soil around the plants at a dose recommended on the bag. By using a fertilizer heavy in phosphate – the numbers on the bag should be around 0-20-0 – your perennial plants and bulbs will grow strong in spring.
The last fertilizer for your trees, shrubs, and bushes should come in late September or early October. Fertilizer promotes root growth, and the nutrients will still be in the soil in spring to feed these plants come out of dormancy. If you have a tree or shrub that doesn’t flower well, a formula high in phosphate helps promote new growth.