A 100-litre container holds a root ball roughly 57 cm across. On a field-grown tree, that ball belongs with a trunk somewhere around 80–100 mm caliper — but the honest answer is that litres describe the container, not the tree. Two nurseries can put very different trees in the same 100-litre pot.
Gulf tender schedules almost always specify pot size in litres alongside a minimum caliper. This page converts between the two, so a specification written in litres can be read against stock quoted in millimetres.
Litres to root-ball diameter
| Container | Equivalent ball diameter |
|---|---|
| 60 L | ≈ 48 cm |
| 80 L | ≈ 53 cm |
| 100 L | ≈ 57 cm |
| 120 L | ≈ 60 cm |
| 150 L | ≈ 65 cm |
| 200 L | ≈ 71 cm |
| 300 L | ≈ 82 cm |
Read the other way: our standard root ball for trees of 100 mm caliper and above is 60–65 cm across and 60–65 cm deep — about 120 to 150 litres. Where a schedule asks for 80–100 L at 50–60 mm minimum caliper, which is a common Gulf specification, our ball comfortably exceeds it. Below 100 mm caliper the ball is made up in coco peat and sized in proportion to the tree.
Caliper, girth and inches
The second confusion in tender schedules is which measurement is meant. Caliper is the diameter of the trunk; girth is its circumference. They differ by a factor of π, so a 25–30 cm girth specification is roughly an 80–95 mm caliper tree — not a 250–300 mm one. We quote caliper in millimetres, measured 1.0 m above the root collar.
| Caliper | Inches | Girth |
|---|---|---|
| 40 mm | 1.6″ | 13 cm |
| 60 mm | 2.4″ | 19 cm |
| 80 mm | 3.1″ | 25 cm |
| 100 mm | 3.9″ | 31 cm |
| 150 mm | 5.9″ | 47 cm |
| 200 mm | 7.9″ | 63 cm |
Why we answer in caliper
A pot size tells you what the nursery put the tree in. Caliper at a stated height tells you what the tree is. It is the one figure a landscape consultant can verify with a tape at the gate, which is why every grade we publish is stated that way, and why our quotations record the measured caliper and height of each individual tree rather than a blanket range.
If your schedule states litres only, send it as written. We will convert it, quote against it, and tell you where the conversion leaves a question worth asking your consultant.