How to plant a tree, step by step
When you plant a tree, the shape of the hole decides how well it establishes: it should be wider rather than deeper, and the top of the root ball, where the root flare is, should stay level with the surrounding soil. Trees are our allies, so when we plant a new one in place of a felled tree, we prepare the hole in exactly this way.
How big a hole to dig when you plant a tree
Kansas State University’s guide says the hole should be two to three times the diameter of the root ball, and the RHS ideally at least three times, but it should be no deeper than the root ball. A Hungarian example is District 16’s tree planting scheme for residents, which asked for a 100 x 100 x 100 cm planting hole for root-balled trees with a 10/12 cm trunk girth.
Whether you’re planting a sapling or moving a tree, the aim is for the roots to spread outwards into loose soil, so in compacted ground loosen the sides of the hole with a fork, and remove the top third to half of the wire basket and hessian from the root ball. Backfill with the original soil you dug out, working it in between the roots so no air pockets remain.
Tap or hover over a layer for details.
- 1. Mulch5-8 cm (RHS), 5-10 cm (Kansas State)
Organic mulch over the planting hole; leave a 10 cm gap around the trunk and don't heap it into a cone, because mulch touching the trunk can cause rot.
- 2. Watering ring
Use the leftover soil to form a low, ring-shaped ridge along the outer edge of the root ball, so that water soaks into the root ball instead of running off. The sources used give no figure for the height of the ridge.
- 3. Root ballhole depth matches the height of the root ball
The root flare, where the roots spread out from the trunk, should be level with the soil surface or slightly above it; when planting, remove the top third to half of the wire basket and hessian.
- 4. Backfill
Backfill with the original soil you dug out, working it in between the roots so that no air pockets are left; Kansas State advises against mixing in organic matter, and according to the RHS fertiliser is of no use at planting time either.
- 5. Loosened sides of the hole
In compacted soil, loosen the sides of the hole with a garden fork so that the roots can spread outwards as well.
- 6. Stakeremove after 1-3 years
Small trees don't need staking, but support a larger or top-heavy tree low on the trunk with a flexible tie, so that the root ball stays firm while the crown can still move. One RHS guide describes a stake driven in at a 45-degree angle; take the stake away after two or three years, or after one year according to Kansas State.
Proportions
- 2-3 times the diameter of the root ball (Kansas State University); according to the RHS, ideally at least three times.
- No deeper than the root ball, so that the root flare sits level with the soil surface or slightly above it.
- In the residents' tree planting scheme run by the District XVI council, a 100 x 100 x 100 cm planting hole is required for root-balled trees with a trunk girth of 10/12 cm.
Caring for a new tree in its first years
- Use the leftover soil to build a low, ring-shaped ridge around the outer edge of the root ball, so water soaks into the root ball instead of running off.
- Spread 5-8 cm of organic mulch over the hole (up to 10 cm according to Kansas State), but leave a 10 cm gap around the trunk and don’t pile it into a cone, because mulch touching the trunk can cause rot.
- If water poured into the hole stands for more than ten minutes, the soil drains poorly, so water carefully.
- Keep a circle at least 1.2 m across free of weeds and grass around the tree for the first three years.
- Check ties in spring and autumn and loosen them so they don’t cut into the thickening trunk.
Frequently asked questions
How deep should I dig a hole to plant a tree?
No deeper than the root ball, so that the root flare, where the roots spread out from the trunk, sits level with the soil surface or slightly above it. Be generous with the width, though, because the roots spread outwards into loose soil.
Should I add compost or manure to the planting hole?
No, Kansas State University’s guide says not to mix organic matter into the backfill, and according to the RHS fertiliser is no use at planting time either. Backfill with the original soil you dug out, and put organic matter on the surface as mulch.
Does a newly planted tree need a stake?
A small tree doesn’t, but support a larger or top-heavy tree low on the trunk with a flexible tie, so the root ball stays stable while the crown can still move. One RHS guide describes a stake driven in at 45 degrees, to be removed after two or three years, or after just one according to Kansas State.
How much should I water a newly planted tree?
Soak the root ball thoroughly after planting, then water regularly for the first one or two years, especially in a drought. In dry weather, the RHS says a tree needs 30-50 litres per square metre each week.
Will you plant a new tree where one has been felled?
Yes, if a tree has to come down, we recommend planting a new one in its place, and we do the planting too. We first grind the old stump below ground level so there’s room for the new tree.
We’ll plant your new tree for you
Planning a new tree, or a replacement for one that was felled? During the free site visit we’ll look at the spot and the soil, help you choose a species and handle everything from digging the hole to staking, and you can write to us in English.
Quicker by phone? Call us on +36 20 944 3464.
