How to Use Stump-Out, Bonide's Tree Stump Remover

Ingredients, Directions and the Burning Question

Image: tree stump.
Does tree stump removal have you stumped?. Liu Track/ EyeEm/Getty Images

Stump-Out is a chemical powder put out by Bonide and available in home improvement stores. It is a stump-remover product that helps accelerate the decomposition of wood. When I heard about this product, it sounded like a good option for frugal homeowners to deal with the last step in tree removal. So I decided to test it.

Putting the power of chemical removal at your disposal, Stump-Out frees you, theoretically, from having to resort to manual stump removal. And as a relatively inexpensive product, you avoid the kind of cost incurred in renting a grinder or hiring a tree service to do grinding work.

How Does Stump-Out Work?

According to the product label, it "dissolves the lignin binding between cellulose layers of the stump making it porous." The key ingredient is sodium metabisulfite (sodium pyrosulphite). Many people associate Stump-Out with burning, but burning is merely an optional step you can take at the end of the project to get rid of a stump more quickly (more on that below).

Preparation: What to Do Prior to Using the Stump Remover

Stump-Out is most effective on tree stumps that have been allowed to dry out. In other words, if you've just had a tree removed (but decided against paying the cost for grinding), you'll want to wait a while before applying this chemical. I conducted my test on a tree that had snapped off in a wind storm; I had waited a few years for it to dry out. Recommended minimal waiting times are:

  • 12 months for a small tree
  • 18 months for a large tree

The more stump you have sticking out of the ground, the longer it will take to break down. I cut mine down to a height of 24 inches. Shorter would have been better, but I settled for the 2-foot height for two reasons:

  • I was using a small electric chain saw not intended for heavy work, so I was hesitant to attempt cutting where the diameter was greatest (namely, at the base of the stump)
  • Since my project was mainly experimental (as a means of reviewing Stump-Out), my main goal was to witness decomposition step by step, as it occurred, rather than achieving the fastest possible breakdown.


Directions for Use

I decided to apply the stump remover 10/17/13. I followed the directions provided as best I could, which run roughly as follows:

  • Drill 4 holes down through the top of the stump (2 holes for small stumps); holes should go down 10 inches and be 1 inch in diameter.
  • Measure about 4 inches down from the top along the sides of the stump, and drill 4 similar holes on the sides (2 holes for small stumps) -- but slanting down at an angle -- in such a way that these holes intersect the bottoms of the vertical holes.
  • Pour 4 ounces of the chemical in each hole (there are 16 ounces per container, just about the right amount for a moderately-sized tree such as mine).
  • Pour water into these holes.
  • Wait about 6 weeks.

At the end of the 6-week waiting period, you then have the option of burning the stump. If, on the other hand, you had already decided against burning, simply check on the progress of decomposition. If the stump has broken down significantly but not enough to proclaim victory, you may wish to complete the job manually (assuming you're in a hurry). If not, buy more Stump-Out and reapply (which is what I had to do; see below under OK, Now for the Reality).

Notes on Using Stump-Out

Drilling the intersecting holes as per the directions above is important in two respects if you plan on burning the stump afterward:

  1. You'll be pouring kerosene or fuel oil into the side holes, and you want this liquid to run down toward the middle of the stump; the slant will make this possible.
  2. The ventilation accomplished by intersecting the tunnels will play a key role once the stump is aflame.

Even though the stump in my project was a few years old, I discovered plenty of hard wood in its center (the heartwood) when drilling the holes. By contrast, bark, cambium, and some of the outer wood on the sides were starting to get punky.

Burn, Baby, Burn?

After the 6-week waiting period, the question then becomes whether or not to take advantage of the burning option. Of course, the decision may not ultimately rest with you. Landscaping rules for HOAs often forbid such activities.

In other cases, homeowners may simply decide against burning. A common objection is, "I oppose using kerosene or fuel oil in such a project because I'm an advocate for green living." No problem: you don't have to set fire to the stump if you don't want to. This will simply mean waiting longer for the wood to break down.

For those who do wish to burn, here are the directions provided by Bonide:

  • Pour kerosene or fuel oil down the side holes.
  • Give the stump time to absorb this liquid
  • Pour additional kerosene on top of the stump
  • Set it on fire, taking the precautions recommended for whenever one uses fire

"The stump will burn with a smoldering red glow down to the roots."

Questions of Safety, Damage to Adjacent Plants, Usability

According to the product label, Stump-Out will not do damage to adjacent landscape plants. Furthermore, the label claims that, even if you take the optional step of adding kerosene or oil at the end of your project, there will be no open flame or explosion.

I'll voice three minor complaints/warnings here regarding the use of this stump remover before offering my overall conclusion below. First of all, it would be more convenient if the container had a spout, since the directions call for pouring the chemical into holes. Currently, the container's cap is designed the way the caps of some salt dispensers are: namely, with a big opening on one side (in case you wish to discharge ample amounts of the container quickly), and a network of smaller openings on the other. Neither is especially convenient for getting the chemical where you want it to go.

Secondly, don't think that you can solve that first problem simply by using a funnel. Lumps tend to form in the powder, impeding discharge through the funnel. I ended up using a screwdriver to break up these lumps and jam the powder down into the holes I'd drilled in the stump. Pouring water into the holes as I proceeded (rather than waiting till later, as per the directions) helped push the chemical down into the holes. But it took a lot longer than expected to work the 4 ounces into each hole.

Thirdly, I question the claim that no open flame is involved if you undertake burning. There may not be an open flame at the end of the process (when the roots are being consumed by fire), but initially there will, in fact, be an open flame if you use kerosene to start the fire.

OK, Now for the Reality

Above I've laid out the basic instructions for using Stump-Out, as stated by the manufacturer. In the ideal scenario, you'll follow those steps to the letter, and in six weeks you'll be rid of the stump. But now -- based on my own test project -- let me paint a more realistic picture. This is how the project is more likely to go for the average suburban homeowner who attempts stump removal via Stump-Out.

As with many DIY projects, a lot hinges on having the optimal tools for the job -- tools which the average person may not have on hand. In my case, I couldn't make a dent in the heartwood of the stump I was attempting to remove using the drill I owned. That wood was just too darned hard. So I was able to make holes only around the perimeter of the stump, not directly in the center.

Still, I went ahead with the project using -- at least in the beginning -- the tools that I had on hand, as most busy people would have done. Going to the store to buy new tools is time consuming and can become expensive.

A second tool-related obstacle I encountered was that I started out with a sub-par drill bit. It was a spade bit that would make a hole 1 inch in diameter. So far, so good. The instructions, however, call for holes of a 10-inch depth; the length of the longest spade drill bit I had on hand was only half of that.

I later went to the store and bought a spade bit extension to experiment with, but I found that my drill's lack of power kept me from maximizing penetration, in spite of the extension.

Tip: if you find yourself shopping for a spade bit extension, make sure you buy a matching spade bit for it. I had assumed that the spade bit I already owned would fit into the extender. It did not. Instead, I ended up having to go back to hardware store to buy a spade bit put out by the same company as the extension (Bosch). See what I mean about how expensive upgrading your tools for a project can become? One purchase sometimes necessitates another, and on and on it goes.

As I state above, I began my project in October of 2013. The stump exhibited no noticeable deterioration during the cold-weather months that followed. It had rotted some when I checked again in spring, and I removed some of this rotted wood, drilled new holes, and added more Stump-Out. By July, there was additional decomposition. Again, I removed the decomposed wood, did more drilling, and applied more Stump-Out.

What was left at this point was mainly the heartwood. It probably wouldn't have been difficult to remove it manually, but I wanted to leave a bit of stump so that I could experiment with burning, which I undertook on August 24, 2014. Following the directions, I ended up pouring about a gallon of kerosene on the stump, then set it on fire. Frankly, I was disappointed with the results. I found that I had almost as much stump left after the fire as before. I aborted the experiment and finished the job with my trusty mattock.


If you're an able-bodied person capable of a little physical work, I would not recommend you bother with Bonide's Stump-Out. By the time you're through running around to buy the Stump-Out, the kerosene, any tools you may need, etc., you could have the tree stump out of the ground using a mattock. The cost to you? Some sweat on your brow and perhaps a tender back. But hey, I get that going to the gym!

True, if you let the Stump-Out sit in the holes of the stump long enough, the wood will eventually break down, even without the use of flame. But that same wood will also eventually decompose naturally (especially if you keep it moist). This product does not seem to dramatically hasten decomposition. So if you don't wish to become good friends with a mattock (or find some other way to remove the stump quickly), I advise simply exercising a bit more patience. Bonide's powder offers no quick fix.