What are Fertilizer Spikes?

Britt Archer

Gardening is a hobby that people have enjoyed for centuries. As time progresses, so does technology, allowing for a greater range of products to help modern gardeners manage their time while still achieving quality results. One such product that gardeners are choosing is the fertilizer spike. Fertilizer spikes are small sticks that can be driven into the soil to provide nutrients to aid in the growth of plants. Nearly all fertilizer spikes operate on the same principles, but there are some important variations.

Fertilizer spikes formulated for trees often contain both quick and slow-release formulas.
Fertilizer spikes formulated for trees often contain both quick and slow-release formulas.

Different nutrients are recommended for different plants. As a general rule, fertilizer spike labels list a series of three numbers, such as 10-10-10. These numbers each represent, by weight, a different nutrient contained within the spike. The first number represents the percentage of nitrogen, the second number indicates the percentage of phosphorus and the third number represents the amount of potassium. Each nutrient benefits a different part of a plant, and this numbering system is an easy and convenient way to figure out which fertilizer spike would benefit a specific garden.

Nitrogen helps with leaf development, and it promotes the process of photosynthesis to create rich green leaves. Phosphorus helps maintain and speed up root growth, and potassium encourages root development and disease resistance. Other beneficial nutrients may be added to fertilizer spikes, and the package should indicate which ones, if this is the case. Yearly soil testing will indicate which nutrients are needed the most, and kits are readily available at most home improvement stores and local health department extensions.

Fertilizer spikes specifically formulated for trees often contain both quick- and slow-release formulas, with some fertilizer tree spikes lasting for up to a year. Tree spikes are specially marked as such, and are often larger than their flower or lawn counterparts. Even more specialized tree spike products are available for fruit trees to encourage more bountiful and timely fruit harvest. Other specialized tree spike products include items for shade trees and evergreens. It should be noted that fertilizer spikes dissolve more rapidly in wet environments, and gardeners should plan their fertilization accordingly.

Many gardeners consider fertilizer spikes the most cost effective way to maintain plant health. Fertilizer spikes may range in price from $2 US Dollars (USD) for houseplant products to $10 USD for tree spike packs. More specialized products, such as eco-friendly fertilizer spikes, may be ordered from online retailers. It is important to follow the manufacturer's instructions regarding proper application and re-application.

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Discussion Comments


@Perdido – I used some citrus tree fertilizer spikes, and I put them around the drip line of the tree. This seems pretty far from the trunk, but that's what the box instructed me to do. I guess that putting them too close to the trunk isn't good for them.

I had to use a hammer to drive them into the ground. This was a big contrast to the kind I use for my potted flowers, because I can push them in easily with one finger.

My tree produced good fruit the following season, so the spikes worked. I would recommend that anyone starting out with a new tree use them.


@OeKc05 – I saw some organic tree fertilizer spikes at a garden center awhile ago, and they were huge. They looked like compacted beige bird seed inside a giant suppository. I know it sounds strange, but it's what I thought of when I saw them.

I've been thinking about getting a couple of trees for my yard, so I was just looking around the garden center to get some ideas. I've never had reason to use these spikes before, because currently, I have no trees.

Has anyone here ever used them? How close to the trunk do you insert them?


I grow tomatoes in a huge pot on my back porch, and I use tomato fertilizer spikes. To me, this is better than growing them in the ground, because it doesn't require any tilling or weeding.

However, you do have to keep the potting soil supplied with nutrients. It doesn't get replenished from the surrounding soil and plant matter like regular earth does, so the fertilization is up to you.

My fertilizer spikes last throughout the summer. After sticking them into the pot, all I have to do is remember to water the tomato plants regularly, and they will grow quickly and stay healthy.


I didn't know that tree fertilizer spikes existed. They must be huge!

The only kind I've ever seen are the tiny ones that are even smaller than a birthday cake candle. They are made for houseplants, and I bought a small pack of them for my indoor herb garden that I keep in my kitchen window.

The herbs loved the fertilizer. They all grew much bushier than they had the previous year. This season, I haven't even had to buy fresh herbs at the grocery store once.

I just hope that I'm not absorbing any chemicals from the spikes that are not good for me. I suppose that it's just as safe as buying herbs from the store, though, because who knows what fertilizers those farmers used.


I have some fertilizer spikes for plant and they're a couple of years old now. Are they still good?

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