How to Fertilize Trees – Know the Proper Method!

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By now most gardeners are aware they need to fertilize their plants but what about trees? Often forgotten, these towering giants need fertilizer, too. Let’s dive in and learn when and how to fertilize them.

How to fertilize trees: Fertilizing your trees is quite simple. You should plan to fertilize at least once a year, either in the spring or the fall. Use a balanced fertilizer and spread it around the tree, being sure to go out to the edge of the root structure. Water afterward to allow the fertilizer to soak into the soil. With proper fertilizer, your tree will have strong branches, large green leaves, and will be healthy enough to fight off most diseases.

Why do you need to fertilize trees?

If you have trees in the wild, they don’t need to be fertilized. This is because the forest area will naturally provide all the nutrients they need. However, in a home garden, much of these nutrients are taken away, usually without you even realizing them.

Part of what makes a home garden stand out is its cleanliness. There are no bits of bark or branches on the ground and the grass is always cut to a proper length.

However, when we tidy up our yards, we are actually stopping organic breakdown that then fuels the soil. When all the leaves are raked up, they can no longer decompose and become a part of the soil.

To this end, if you want to keep a neat and tidy area, you should add fertilizer to your tree. This will restore the soil to its natural balance and keep your tree nice and healthy.

How to know if your tree needs fertilizing?

Sign 1 – weak branches

Trees that do not have enough nutrients aren’t able to grow properly. There will still be branches but they won’t be as stiff as they should be, nor will they be as long as a healthy tree.

If you constantly have branches that break off during a wind storm, it means your tree is not as strong as it could be. Also, look for short branches that don’t seem to grow during each new season.

Sign 2 – small leaves

While your tree will still produce leaves, if it needs fertilizer, these leaves will be small in size. As a result, the canopy of your tree will be thin, and therefore unwanted growth lower down the tree can occur.

Sign 3 – yellow or brown leaves

Even though most tree leaves will eventually turn yellow, they shouldn’t do so before their time. If you have a tree that isn’t green in late spring or early summer, when it is at its peak, then it may mean it is lacking in important nutrients.

How do you apply fertilizer to trees?

First, pick your fertilizer, which should be a basic 10-10-10, which includes nitrogen, phosphorus, and potassium.

Then, determine the expanse of the root structure, which is usually the whole area under the tree’s branches

Apply the granular fertilizer to the ground under the tree, starting about a foot away from the trunk. Spread it evenly and stop when you get to the end of the root zone

Water liberally so that the fertilizer can really sink into the ground. You don’t want there to be a crust of fertilizer afterward as this means the nutrients have not gone into the soil.

When should you fertilize a tree?

A lot of people worry about when the right time is to fertilize their trees and as a result, can make the whole process a lot more complicated than it needs to be. Instead, you can relax a bit as there are two opportune times for fertilizing.


Fertilizing plants, trees, and shrubs in the spring is a common occurrence, and for good reason. This is the time when your garden starts coming back to life and you want it to have the best advantages possible.

You can fertilize your trees in the spring, once the ground starts to warm up. The fertilizer needs to be able to penetrate into the soil so if the ground is still frozen, it won’t be able to work properly.

When you fertilize in the spring you can expect your trees to have lovely green leaves, sturdy branches, and less disease.

If you have fruit or citrus trees, it is especially important to fertilize your trees in the spring as this will help the fruit grow during the summer.


Even though your trees are about to enter a period of dormancy, you can still fertilize in the fall. This will help the soil recover from all the work it has done during the spring and summer.

You do want to get the fertilizer into the ground before it freezes over, however. Aim to fertilize in the early to mid-fall, before the first frost, and definitely before the first snowfall.

What fertilizer is best for trees?

Trees are continually growing so you want to match the fertilizer with your tree’s needs. Always try to use a fertilizer that has a slow release.

This means that the fertilizer will continue to work for a few months after you add it, so your tree will have a continuous source of nutrients.

A quick-release fertilizer is better for plants that have a small growing season, as they will need a good burst of nutrients to grow, whereas trees will be alive for decades and thus need their soil to always be in good condition.

Trees need three key nutrients, which are nitrogen, phosphorus, and potassium. A basic tree fertilizer will have these in a ratio of 10-10-10, which should be good for most soil conditions.

You can also test your soil to see if there are any extreme deficiencies and then modify the fertilizer ratio accordingly.


Trees are an important part of any yard and we don’t want to neglect them. Add a slow-release fertilizer in the spring or fall so that your trees remain healthy, green, and full of life.

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