Can Fertilizer Spikes Kill Trees?

You might consider fertilizer spikes to improve the soil conditions in your landscape. But, while trying to improve plant health you might wonder if fertilizer spiks can kill nearby trees. What are the spikes made of? Read on and find out what our research revealed.

Fertilizer spikes are safer and more convenient than other applications because of the slow-release feature that gradually delivers nutrients into the soil. However, they can weaken trees and possibly kill them if they are placed too close to the trunk.

Properly placing the correct number of spikes would determine how they affect the tree.

Fertilizer spikes provide a safe and convenient way to amend the soil, but the proper application method would determine how it would benefit your tree. The article includes all you need to know to fully optimize the use of the product.

What Are Fertilizer Spikes?

Applying fertilizer spikes on a pot of growing potatoes

Fertilizer spikes are small hardened columns with a tapering end that contain compacted plant nutrients designed to be released gradually over time. The composition is pre-mixed and formulated according to the particular plant they are applied to.

Interestingly, the release of nutrients is influenced by soil composition and bacterial activity. Essentially, the fertilizer spike delivers the optimal amount of necessary augmentation at the appropriate time. Watering and rainfall do not considerably impact the spikes' slow release.

Due to this, fertilizer spikes are dissolved and consumed at different rates and have to be reapplied without any particular timeline or schedule. Generally, however, the product can be used an average of two per year.

What Are Fertilizer Spikes Composed Of?

What fertilizer spikes composed of, Can Fertilizer Spikes Kill Trees?

Fertilizer spikes are mainly composed of nitrogen, phosphorus as well as potassium (NPK) and are supplemented by micronutrients, namely, iron and manganese, needed for plant growth and development.

The actual formulation will depend on the specific tree or plant and the nutrient makeup of the soil.

To illustrate, spikes used for fruit trees contain high doses of phosphorus and potassium and fewer amounts of nitrogen. This way, the plant will focus its energy on producing yield rather than on leaf development.

How Do You Use Fertilizer Spikes?

A package of Miracle-Gro tree & shrub fertilizer spikes

Determine and plot the placement and number of fertilizer spikes you need using the tree's dripline as a reference point. It is the area around the tree where the canopy ends or the foliage extends its reach.

Before you drive the spikes into the ground, water the area thoroughly to soften and loosen the soil. Position the spike and gently pound on the plastic driving cap, preferably with the use of a rubber-tipped mallet, until the entire shaft is a few inches below the ground level.

The material may snap or shatter if you fail to dampen the soil or use a regular hammer. To prevent this, a better way would be to drive a wooden stake to make a hole and then simply place the fertilizer spike in it.

How Many Spikes Should Be Used Per Tree?

To determine the number of fertilizer spikes you are required to use per tree, you should first find out the diameter of the tree’s trunk using a caliper. At least one spike is needed for every two inches of its diameter. So if the measurement is six inches, you will need three fertilizer spikes.

Remember to space the product three feet apart and place them under the tree’s drip line. Do not put it too close to the trunk to avoid harming the tree.

If you do not have a caliper, you could use two sticks to calculate the diameter. Simply place the stakes on opposite sides of the trunk and measure the space between the two rods.

The measurement may not always be precise. If this occurs, round it off to the nearest even number and then determine the number of spikes you need. To illustrate, you get a measurement of 13 inches, you could round it off to 14 to make the calculations easier. In this case, you will need seven spikes.

Check out Miracle-Gro Tree & Shrub Plant Food Spike on Amazon.

What Are The Advantages And Disadvantages Of Using Fertilizer Spikes?

Fertilizer spikes are relatively safe and convenient, but their proper usage and effectiveness would determine their benefits on trees and other plants.

What Are The Advantages Of Using Fertilizer Spikes?

  • The spikes dissolve gradually and deliver nutrients into the soil in controlled amounts over a relatively long period. This eliminates the possibility of root shock and leaf burn and lessens the frequency of fertilizer application.
  • The content is pre-measured, so there is no possibility of over-fertilizing trees, shrubs, and other plants in your garden.
  • The product is encased and staked into the ground rendering it safe for children and pets. It also eliminates runoff odors common to conventional fertilizers.
  • Fertilizer spikes are convenient, quick, and easy to apply, handle and store compared to granular or liquid forms.
  • They are available in pre-mixed formulas designed for particular and specific plant types, such as trees, ornamentals, vegetable gardens, and flower beds.
  • They have a special feature that promotes and increases plant resistance to infestation and disease.

What Are The Disadvantages?

  • Fertilizer spikes are considerably more costly than regular granulated or liquid amendments. It may not be practical to use if your garden has several trees.
  • Sometimes the spike can shatter when driven into the ground.
  • The nutrients are distributed and concentrated within a limited area of the root system.

When Is The Best Time To Fertilize Trees?

Heap of houseplant fertilizer spikes on white background

Fertilizer spikes contain specific proportions of macro and micronutrients needed by plants. It is necessary to determine the nutrient composition as well as the amount of nourishment present in the growing medium so as to prevent over and underfeeding.

According to experts, trees are most vulnerable to diseases and infections during the spring, making it the ideal period for fertilizing. Proper feeding keeps the plant healthy and increases its resistance to various diseases.

Fall feeding is equally important because the tree may have depleted the nutrients present in the fall during the growing seasons. As a result, they receive only less of the required nourishments to prepare themselves in the winter months.

Ideally, it is advisable to fertilize your tree at least two times a year, one in the spring and another in the fall.

Young trees should not be fertilized since their roots are only beginning to form and develop. They are most at risk of chemical burns. That being said, you must give the tree ample time to mature and become established – at least one to two years of age.

Are There Different Fertilizer Spikes Designed For Particular Plants?

Applying fertilizer spikes to a tomato plant

Since fertilizer spikes contain different proportions of nutrients as well as organic and inorganic matter, they are designed for specific use of particular plants, including vegetables, various kinds of trees, and shrubs.

Check out Jobe’s Vegetable And Tomato Fertilizer Spikes on Amazon.

It is important to use a product designed for specific plants or varieties to not negatively harm or affect your vegetation.

Fertilizer spikes measurement varies depending on which plant you intend to use the product. Shrubs require at least one spike for every three feet of their height. This way, you can avoid over-fertilizing them.

Check out Jobe’s Fertilizer Spike For Evergreen Trees on Amazon.

Can You Crush Fertilizer Spikes?

Fertilizer spikes are slow-release fertilizers made with precise amounts of nutrients and are not designed to be crushed. Although it is possible to use a crumbled form of the product, you won’t be able to control the amount of nourishment released onto the soil.

During application, if you accidentally crumbled the spike, you can crush them into granules and spread them evenly around the trunk of the tree several inches from its base.

Since mulches become too compact, the roots will have difficulty absorbing the nutrients. Remove the mulch before application so as to not affect the product’s effectiveness.

In Closing

Fertilizer spikes help prevent fertilizer burn and limit the need for frequent application. Place the right number of spikes equally spaced along the dripline to avoid harming or killing your tree. We hope the article has been helpful.

You might also find these topics informative:

How Much Fertilizer Should You Use For Fruit Trees?

How Long Does Fertilizer Last In Soil?

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