In addition to fall being a great time to get new plants in the ground, it can also be an ideal season to fertilize your lawn, trees, shrubs, and perennials. But you have to do it correctly: During these cooler months, plants are slipping into dormancy and not actively growing. Depending on how severe or mild your winter is, they can be anywhere between completely dormant to growing very, very slowly. If you fertilize right, you’ll be giving them the best send-off to their winter sleep.
Before you start, you may want to get in touch with your local cooperative extension. They can help you get a soil test (you can’t help your plants if you don’t know what they need). And they can tell you the first frost date for your area (for practical purposes, fertilizing should be done before the first frost). They know your climate best and can give you advice specific to your location.
Note: We don’t recommend using synthetic fertilizers because of the large environmental impacts associated with them, including water contamination from run off and decimation of soil microbes. Restoring soil health naturally should always be the first option.
Here’s what you need to know about fertilizing (naturally) in the fall.
For the Lawn
The best and easiest way to fertilize is to do one last mow with a mulching mower and leave the clippings on the lawn. Mulching the clippings back into the lawn can provide up to 50% of the needed nutrients for the grass. To make up the rest of what your lawn needs, there are two low-cost and environmentally sustainable ways to fertilize. First, you can aerate the lawn and top dress with compost. Second, if you have fallen leaves, mulch them into the lawn as well. Just remember to rake them around so they aren’t too thick. It is a smart idea to keep the nutrients created on your property, on your property. (See Ask the Expert: Doug Tallamy Explains Why (and How to) Leave the Leaves.)
A more expensive, less eco-conscious option is to use organic lawn fertilizer. While organic fertilizers are certainly better than chemical fertilizers, there are still manufacturing and transportation costs to the environment. If you go this route, follow the directions exactly. More is not better.
For Trees and Shrubs:
A closed loop is the best type of fertilizer. Keep the leaves from the trees under them. They have everything the trees need—for free. They help on so many levels. They act as mulch and keep the moisture in the soil, which in turn helps the microbes that break down the leaves, making their nutrients available to the trees. The leaves also become winter homes for good bugs. Just be sure to keep the root flare exposed; piling the leaves up the trunk can cause can cause the bark to rot. No trees on your property? Organic compost is your next best choice.
For shrubs that were healthy over the growing season, a leaf well around the base will be enough. If they didn’t do well over the summer, they may need a bit of help. Aerate the soil and add some compost and water well.
If you want to add store-bought organic fertilizer to your tree or shrub, you may want to consider consulting with an arborist first. It’s easy to over-fertilize and cause damage. Leave it to the professionals.
For Perennials:
Yes, leaves again. Really. And compost. Both the leaves and the compost break down slowly. Nobody is in a rush here, it’s winter and nothing is growing. The idea is that the nutrients will be ready and in a form the plant can use once it wakes up in the spring. If you’re concerned about burying your plants too deep in leaves, lightly cover what remains of your almost dormant plants, but pack the leaves thickly around them.
There are no other real options. If you use synthetic fertilizer while they are going into dormancy, they could come out of dormancy early during an extended warm spell—and then when a cold snap follows, the new growth may be killed. This can weaken the plant, causing it to fail to thrive in the spring or even die.
Our gardens are part of a larger ecosystem, so it’s important to prioritize soil health and natural methods over synthetic fertilizers. Aeration of compacted soil and addition of organic matter will have a better and a longer-lasting effect on plant health.
See also:
- 6 Nature-Based Garden Tasks for Fall
- Gardening 101: How to Propagate Your Annuals this Fall for Next Summer
- What’s Causing Your Fall Allergies? It’s Not What You Think
Frequently asked questions
What is fall fertilizing?
Fall fertilizing is the practice of applying nutrients to your plants and soil during the autumn season. It aims to provide essential elements that promote healthy growth and prepare the plants for the winter months.
Why is fall fertilizing important?
Fall fertilizing is important because it helps replenish the nutrients that may have been depleted during the growing season. It ensures that the plants have enough energy and resources to survive the winter and encourages stronger growth in the following spring.
What nutrients should be used for fall fertilizing?
A balanced fertilizer that contains nitrogen (N), phosphorus (P), and potassium (K) is usually recommended for fall fertilizing. These essential nutrients promote root development, overall plant health, and help with nutrient uptake.
When should I start fall fertilizing?
Fall fertilizing should ideally be done a few weeks before the first frost, giving the plants enough time to absorb the nutrients and prepare for winter. This timing varies depending on your location and the specific plants you have.
How do I apply fall fertilizer?
Fall fertilizer can be applied by broadcasting it evenly over the soil surface or by using a spreader. It's important to follow the instructions on the fertilizer package for the correct application rate. Water the area after application to help the nutrients seep into the soil.
Is fall fertilizing suitable for all plants?
Fall fertilizing is generally beneficial for many types of plants, especially those that enter dormancy or have a longer growing season. However, some plants may have specific fertilizer requirements or may not require fall fertilizing at all. It's best to research the particular needs of your plants or consult a gardening expert.
Are there any risks or precautions associated with fall fertilizing?
While fall fertilizing is generally safe, it's important to follow the recommended application rates to avoid over-fertilizing, as this can harm plants or leach excess nutrients into the environment. Additionally, avoid fertilizing plants that are stressed, diseased, or newly planted. It's always a good idea to read and understand the instructions provided by the fertilizer manufacturer.
Can I use organic fertilizers for fall fertilizing?
Yes, organic fertilizers can be used for fall fertilizing. They provide nutrients in a slow-release form and improve soil fertility over time. Organic fertilizers also enhance microbial activity in the soil and promote a healthy ecosystem.
Should I fertilize my lawn in the fall?
Fertilizing your lawn in the fall is beneficial as it helps the grass recover from summer stress and encourages root growth. Look for a fertilizer specifically formulated for lawns and follow the application instructions carefully.
What are some alternatives to fall fertilizing?
If you prefer not to use fertilizers, there are alternative methods to improve soil fertility in the fall. These include applying compost, mulching with organic materials, and practicing crop rotation. These natural methods help enrich the soil and support plant health.
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