Tips & Advice

Understanding Plant Bag Volumes

Man with Plant Bag looking confused

Why does my Plant Bag look smaller than I thought it would?

This is one of the most frequently asked questions we receive about Plant Bag Volumes and Sizes.

Sometimes when we send some 1 litre or 2 litre bags to a customer, they get a bit of a shock thinking they have ordered something visually bigger than what they have received. Here are a few points to consider when choosing the right sized bag.

Firstly, we are conditioned by large companies in the food and beverage industry to see a 2 litre container looking quite large. It’s all about marketing – perceived value for money. The bottles tend to be ‘ornate’ with curves, indents and handles or with a taper at the top (and even the bottom). All of these things effect the way we view a container volume, and even a 9 litre household bucket is quite tapered and has some indents etc. In addition to this, consumer liquid containers are rarely filled to the top.

For many decades, the unit of measurement for a Plant Pot is the measurement across the top of the Pot (Diameter) – like for example a 200mm pot. For some reason however, the industry instead measures a Planter Bag in terms of how many litres of mix it holds. This is probably because several bags that have the same diameter will hold a different volume depending on the height of the bag. Our 2.5 Litre, 4 Litre, 5 Litre tall, 6 Litre tall and 7 Litre tall bags, for example, all have a similar diameter, but they just get taller. 

Typical juice/Milk Container
Typical juice/Milk Container
2 Litre Plant Bag
2 Litre Plant Bag

In some sizes, a small change to the numbers can make a big difference to the volume! For instance, if we were to put a 2 litre milk bottle (average height 27cm) next to a 2 Litre planter Bag (height 17.5cm) it has them looking quite a bit different to each other in size, but actually both holding 2 litres.

Planter Bags have no ‘Taper’ which means it is the same width at the top as it is at the base. This element alone will make a large difference to the volume of mix it can hold.

When we talk about the measurements of a bag, we like to use the ‘filled’ measurements, or the diameter and height once the bag has been opened up and filled with mix (like the picture below). Many farms and nurseries still talk in terms of the ‘lay flat’ measurements (folded flat in the box).

The next picture shows a 75 L bag and a 50 L pot. Obviously the pot has been super-imposed into the Bag picture and is therefore only an example, but the size of these 2 containers actually appear similar in real life. The pot, because it is wider at the top than it is at the base (taper) holds much less mix compared the bag.

The Actual measurements of these 2 containers are;

75 Litre bag – Diameter 460mm x Height 460mm. (Inside Diameter 460mm, Base Diameter 460mm)

480mm (50L) Pot – Diameter 480mm x Height 400mm. (Inside Top Diameter 435mm, Base Diameter 380mm)

We hope that helps a bit when you are next choosing your Plant Bag Size. Healthy gardens to you all!

Volume comparison - Bag vs Pot
Volume comparison - Bag vs Pot