sizes of pots for plants

How to Choose the Right Pot or Planter for a Plant

Introduction: How to Choose the Right Pot or Planter for a Plant

Choosing the right pot for the right plant is very important! The planter you choose will affect how the quickly soil dries out, how well a plant grows, and how healthy the roots are.

There are three major categories of pots: ceramic/glazed, terra cotta/clay, and plastic. I’ll walk you through the pros and cons of each category. I’ll also cover using containers without holes for plants, as well as which size pot you should choose when replanting.

Water and light might be the most important parts of keeping healthy plants, but the right pot is the cherry on top!

Step 1: Pros and Cons of Terra Cotta (Clay) Pots

I personally love terra cotta pots! I would say about half my plants are potted in them. They’re easy to find where I live and are pretty standard as far as shape and size, so you can find matching pots easily.


  • Terra cotta dries out quickly, making it perfect for succulents and other plants that hate sitting in water.
  • Cheaper than ceramic pots.
  • Neutral in color, looks great with plants.
  • Ability to see current moisture level based on pot color. (The terra cotta will soak up water and turn a darker color)


  • If you drop one of these, chances are it will shatter. They’re fairly delicate!
  • Can dry out exceptionally quick in places with high temperatures and low humidity, so make sure to keep an eye on new transplants.
  • Can crack due to cold temperatures in winter.

Step 2: Pros and Cons of Plastic Pots

Plastic pots are the cheapest and easiest to obtain no matter where you are! The majority of plants are sold in plastic pots, so it’s simple to amass a large quantity of them in no time. I keep all the plastic pots I buy plants in, wash them, and reuse them. They’re great for starting seeds or plant propagation!

Plastic pots keep water in the soil for much longer than a terra cotta pot, so it’s very important to have drainage holes in the bottom of the pot to prevent root rot.


  • The cheapest plant pot around!
  • Come in a large variety of shapes, colors and sizes.
  • Lighter than ceramic or terra cotta.
  • Easy to wash and reuse.


  • Can become faded and brittle in the sun.

Step 3: Pros and Cons of Ceramic or Glazed Pots

I adore ceramic pots but don’t use them for many of my plants. They look gorgeous and come in so many interesting shapes! Because they can be so heavy, I really only use them for small plants and succulents. I like to walk my plants to the sink to water them, and a huge ceramic planter would make that tough!


  • Great for tropical plants and plants that enjoy moist soil.
  • Sturdy and attractive.
  • Heavy enough to keep top-heavy plants from falling over.


  • Incredibly heavy when large in size. I do not recommend for big plants that you plan on moving around often.
  • The most expensive type of pot (unless you luck out and find some on sale!)

Step 4: Using Containers Without Holes for Pots

(The photo above is my first plant [a haworthia] in its new pot and the original hole-less pot it came in. While I kept it alive in the first container, it didn’t grow and thrive until I repotted it!)

This is something I really only recommend in one of three cases:

  1. You’re familiar with the light and water needs of the plant you’re growing and have successfully grown it in a normal pot. OR
  2. You’re able to drill holes in the bottom of the container. OR
  3. You can place a pot with drainage holes INSIDE the hole-less pot.

Drainage is VERY important to keep plants healthy. Containers without a drainage hole can lead to water collecting in the bottom and causing root rot. (Root rot is often fatal for plants and nearly impossible to reverse.)

Ceramic and terra cotta containers can be drilled using a masonry drill bit, and plastic containers can be drilled using almost any sharp drill bit. There are loads of guides online for doing this, so I highly suggest looking up how to drill into the material your container is made of.

Using a cheap plastic pot inside of a decorative container is another clever way to get drainage without drilling into the container. This is also a good way to protect containers such as woven grass or fabric baskets.

Step 5: Choosing the Right Size Pot for Your Plant

This is one of those things about gardening that can be really confusing for beginners: how do you know which pot size is the right size for your plant?

Here are some basic guidelines!

Choose a pot that’s comparable to the size of the plant

Many plants enjoy having room to spread out, but too much or too little room can cause problems! Pots that are too big can cause a plant to sit in water for too long or cause nutrient burn from the large amount of nutrients the soil ends up holding. A pot that’s too small can cause a plant to become rootbound, leaving very little soil available to hold on to water.

Don’t make a drastic jump in sizes

If you have a plant in a four inch pot, it’s best to move up to the next size – a six inch pot! Don’t go crazy and double the pot size, as it will take a long time for the plant to fill the pot and increase your chances of over watering it.

Choose deeper pots for plants with large roots, and shallower ones for plants with small roots

Large houseplants with a ton of foliage tend to develop deeper, larger root systems and can handle being put in a pot as tall as it is wide. Succulents and cacti do well in shallower pots.

If all else fails, check the roots

If you’re really unsure about which direction to go, gently remove the plant from its current pot and check the roots. Are they filling out the pot? If so, go up a size. If you see an equal amount of soil and roots, chances are the plant is fine in the current pot size. If you see loads of soil and very little roots, you may want to go down a size if the plant or its roots look unhealthy.

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How to Choose the Right Pot or Planter for a Plant: Choosing the right pot for the right plant is very important! The planter you choose will affect how the quickly soil dries out, how well a plant grows, and how healthy the roots are. There are three major categories of pots: ceramic/glazed, terra c…

Plant Pot Sizes: The Complete Guide

Why are there so many different pot sizes on the market?

Nurseries sell plants at different stages of growth. Most are grown in the ground and then transferred into a pot. Thus a 1 year old tree may be transferred into a 9L pot, a 3 year old tree into a 18L pot. Others are transferred from pot to pot, from a 3L to a 9L for example.

Thus a tree may start out in the ground, before being transferred to a 9L and then a 15L, and so on. A nursery may start out with 300 trees and sell 150 bare root, 100 9Ls and 50 15Ls. Although, not all nurseries do this. Thus a tree may remain in a pot it was initially transferred to.

Different nurseries sell their plants at different stages of growth and use different size pots. This increases the number of pot sizes on the market.

Is pot size a good measure of value for money?

No. You don’t want a larger pot of soil, but a healthy tree with a well established root system and lots of growth. Thus, you should look at the height on arrival and the age of a tree. For larger tree sizes, looking at a tree trunk’s girth is a good measurement of value.

One particular pot size may seem very competitive in comparison to another, but this does not mean you are getting better value. Some nurseries set up complicated irrigation and fertiliser systems ensuring trees receive the best possible nutrients, while others do not go to such lengths.

Similarly, the age of a tree is not the be all and end all. A well fed tree will grow faster than a poorly fed tree. This is why you look at the height on arrival also.

Are smaller or larger pots better value for money?

The younger the tree you purchase the easier it will establish and easier it will be to train. The older the tree you purchase the greater the instant impact it will make and the less you will have to wait for fruit.

Why are 9cm pots not marketed in litres?

Interestingly, 9cm refers to the pots diameter, as opposed to height. All pots smaller than 1L are listed this way, probably because receiving a 0.43L pot sounds a bit rubbish.

Are all trees supplied in pots?

Trees can be sent from late autumn to early spring when they are dormant without any soil – these trees are known as bare root. Potted trees can be transferred anytime in the year, although are best purchased and planted in the colder months as to avoid water stress.

9cm Pot

The smallest pot size available. Plants supplied are usually herbs and shrubs. Many hedging plants are sold this way, allowing you to grow a hedge on the cheap.

2-3L Pot

Climbing plants, both fruiting and ornamental, as well as shrubs are sold at this size.

Roses are sold at this size as their roots grow deeper than other shrubs.

The smallest pot size, you’ll likely be able to buy a tree at.

9-12L Pot

The standard size for 1-3 year old trees. Trees are transferred into this larger pot size, either from the ground or 3L pots.

As young trees are transferred to these larger pots after the bare root season ends in spring, buying in Autumn is recommended, when the tree has adapted to the pot and had more time to grow. A downside of this is that some varieties may have sold out by this point, so for lauded trees buy early!

This is the first size standards are available at. Standards have a portion of the trunk cleared of stems for ornamental value.

Trees above this size are marketed as producing an instant impact.


Trees are available in a large number of pot sizes in this range – 15, 18, 25, 30, 45, 50 and so on – with larger pots containing older, more mature trees. The greater the maturity, the greater the instant impact.

Fully grown trees are supplied at this point and at great cost, due to the cost of delivery and years in the nursery.

Approximating Plant Pot Sizes

Litres are difficult to approximate without prior knowledge. Below, you can see our infographic of the relative size of different litre plant pots.

Calculating Plant Pot Sizes

Comparing plant pot sizes is difficult as they vary in shape by manufacturer. At small sizes plant pots are flat-topped cones, while larger sizes are more structurally stable cylinders. This is why we recommend you calculate a pot’s litreage yourself.

Most plant pot sizes are measured in litres, which is a measure of volume, calculated from a shape’s cubic centimetres. A cylinder’s cubic centimetres is calculated from the equation πr 2 h. Thus to calculate you plant pots literage, you need to measure your pot’s height and radius with a ruler. If your plant pot isn’t an exact cylinder, but a flat-topped cone, it is best to approximate calculating a cylinder.

If your pot is a square or rectangle, calculating the cubic centimetres is easier. Simply, multiply the height by the width by the diameter.

Now you have calculated the cubic centimetres of you pot, simply divide by a thousand to arrive at litres.

Too complicated? Below you can see the measurements of various cylindrical pots that were visualised in the above infographic. In our calculations we have presumed the radius is two/thirds of the height.

In the table, you can see that a 3L pot is 44% larger than a 1L pot. Luckily, a cylindrical 3L pot will always be 44% larger than a 1L pot, regardless of the ratio of radius to height.

From the table, you can calculate how much larger a 25L pot is to a 1L pot by calculating percentage change. Simply minus the old height from the new height, then divide by the original height and then multiply by hundred. ((26.16-9)/9) x 100. Thus the percentage change is 190.67%.

We know this is correct as if we multiply 9 by 2.9067 (converting the percentage to a decimal) we arrive at 26.16.

Jorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!

His ideal afternoon would involve a long walk, before settling down for scones.

Jorge is a journeyman gardener with experience in growing crops.

Why are there so many different pot sizes on the market? Is pot size a good measure of value for money? And learn how to calculate the perfect pot size!