Choosing a suitable tree stump
If you have a choice of tree stumps, and you’re not sure which ones to consider hollowing out for plants and which ones to remove entirely, look at both the location and the size, condition and species of each stump.
The location of the stump will determine which plants are likely to do well, so choose a stump that is either shaded or exposed accordingly. Smaller stumps are preferable as long as they are wide enough to enable the plants to thrive. Some species of trees make more durable planters than others. Oak and cedar stumps are often ideal for hollowing out for this purpose.
Any tree stumps intended for planting must be free from decay, pests and fungus. Any diseased stumps should be professionally removed to stop the disease from spreading to healthy trees and plants.
How to hollow out a tree stump for planting manually
One of the safest methods for hollowing out tree stumps does involve some manual labour.
First, level the top of the stump using a chainsaw. Make sure you wear thick gloves and eye protection, and follow all the safety advice contained in the chainsaw user manual. In particular, make sure that people and animals are kept well away from danger.
Ideally, wait for some heavy rain to soften the stump before moving on to the next stage. If rain is not in the forecast, or you don’t want to wait, give the stump a soaking using a hosepipe.
Drill a series of holes into the top of the stump, three or more inches from the outer bark, to form a circle. Each hole should be angled 45 degrees towards the centre of the stump. Drill four or five equally spaced holes around the bottom of the stump, angled upwards, for drainage.
Next, use a hammer and chisel to gouge out the wood between the holes. A carving gouge is ideal because the curved edge of the tool will help you create a nice even finish.
Work your way inwards until you have hollowed out the interior of the stump to the depth required. How deep should your planter be? Eight inches will be enough for most purposes, but you can go as deep as you like if you are willing to put the extra work in.
For an attractive finish, sand the interior and remove all wood scraps and shavings.
For extra drainage, add some gravel to the base of your finished planter before filling it with soil and compost. Some people add chunks of charcoal along with the gravel to help control odour.
How to hollow out a tree stump for planting using fire
Do you want to know how to hollow out a tree stump for planting without putting in quite so much manual effort? You can bypass the chiselling with some carefully placed chemicals. Your chosen stump must be 15 metres or more from your property or any other flammable structures (fences, telegraph poles, etc.) For this method, your stump should be as dry as possible.
Follow the instructions for the manual process above, but drill your holes a couple of inches apart and at an angle of 30 degrees. You then fill the holes with saltpeter, leaving half an inch at the top. Pour hot water into the holes until they are full.
Cover the top of the stump with scraps, cardboard or similar kindling material and ignite. Once the stump has burned and the fire has died, you can return to safely scrape out the charred wood.
Disclaimer: Fire is inherently risky. In providing the information above, Kneebone Trees is not recommending this method for your specific circumstances. We can’t be held responsibility for any damage or injury caused by deciding to use fire to hollow out a tree stump.
Take a look at our tree planting service
Kneebone Trees offers a specialist tree planting service suitable for both domestic and commercial customers. For practical support or advice on how to hollow out a tree stump for planting, or on choosing the right plants for your tree stump planter, contact the team.
