What Is Up With Nursery Plant Sizing?!
If you’re browsing our site and thinking, “Why are there so many sizing options — and why don’t they match how big the plant looks?” you’re not alone. Nursery plant sizing can feel confusing, especially when you’re comparing container sizes, liter measurements, caliper, and height all in one place.
Plants aren’t sized the way most products are. Instead of being labeled by how tall or full they appear, nursery plants are sized using industry and state standards that focus on things like root volume, trunk diameter, or overall height. These standards exist to create consistency and fairness — even though plants themselves are living, growing, and naturally variable.
On top of that, different growing methods (container-grown vs. field-grown), Colorado’s liter-based container sizing, and natural plant-to-plant differences can make sizing feel a little… weird.
The good news? Once you understand what these sizes actually represent, choosing the right plant becomes much easier. This guide breaks down the sizing terms you’ll see on our site so you can shop with confidence and know exactly what you’re getting — and why it’s labeled that way.
Container Sizing Explained
Container sizing is not based on the height of the plant or the outside dimensions of the pot. Instead, it reflects the actual volume of soil and root mass inside the container. This system exists because nursery pots can vary in shape and size, even when they hold the same volume.
Colorado follows industry and regulatory guidelines that require container-grown plants to be sold by root/soil volume, expressed in liters, rather than by pot appearance or plant size. This helps customers make accurate comparisons and know what they’re purchasing.
What does volume sizing tell you?
The liter (L) size gives valuable insight into:
- The established root system
- The plant’s ability to handle transplanting
- Expected establishment and growth potential
Container Sizing Conversions
| Nursery Size | Metric | U.S. |
|---|---|---|
| #1 | 2.48L | 2 Qt |
| #2 | 6.19L | 1.6 Gal |
| #3-5 | 10.44L | 2.8 Gal |
| #6-7 | 15.65L | 4.1 Gal |
| #10 | 33.72L | 8.91 Gal |
| #15 | 46.78L | 12.4 Gal |
| #20 | 86.98L | 22.98 Gal |
| #25 | 104.50L | 27.6 Gal |
Examples Of Container Size
Wondering what these container sizes look like in real life? Take a look at our staff members posing by some of our container selections:
2.48 L or #1 Containers
15.65 L or #7 Container
10.44 L or #5 Containers
46.78 L or #15 Containers
33.72 L or #10 Container
B&B Sizing Explained
Balled & burlap (B&B) trees are field-grown trees that are dug with an intact root ball, wrapped in burlap, and secured for transport and planting. Unlike container-grown plants, B&B trees are not sized by soil volume. Instead, they are sold based on caliper or height, depending on the type and size of the tree.
Caliper sizing
Caliper refers to the diameter of the tree’s trunk and is the most common sizing method for deciduous shade and ornamental trees.
Caliper is a reliable indicator of a tree’s maturity, strength, and structural development. A larger caliper generally means a more established tree with a thicker trunk and more developed branching structure.
Height sizing
Some trees — especially evergreens and certain specialty trees — are sold by overall height instead of caliper. Height is measured from the base of the trunk at the soil line to the top of the tree.
Height-based sizing helps customers understand the immediate visual impact of the tree in the landscape, particularly for screening, windbreaks, or privacy plantings.