Does pot shape and size affect growth? Yes it does.

Just like an man’s home is his castle, a plant’s pot is its palace. The pot is a place of safe refuge, a room to call one’s own, and a space to not just live but to grow and flourish. Hence, matching your beloved plant to its pot is not something to gloss over but is worth careful deliberation.

Knowing that containers are an important consideration can be overwhelming when you realize the spectrum of available pots. You will be surprised to find that different shapes, sizes, materials, colors, styles, weights, etc. of flower pots have so much impact on the plants inside. We know this, so we compiled a guide to help you choose the best shape and size of your next planter!

Plant Size Mean?

You may have seen plants described in sizes i.e., in inches or gallons. This does not refer to the actual plant. Here, inches refers to the diameter of the pot that the plant came in while gallons is in reference to its container volume. Take for an example a 10” plant, this is a plant that is growing in a 10” diameter pot, or in a pot that is usually 2.5 to 3 gallons.

Most pots fit loosely into a system that increases by 2” starting from 2”, then 4”, then 6” etc. This range is endless with some of our own products reaching sizes of 60 inches.

Houseplants will usually have a small size pot that is convenient for the home, allowing accessibility to move it around and perch it on shelves and tables.

When container gardening with outdoor plants, the plant size will need to be larger to allow for stability in the wind and other outdoor elements.

What Pot Size Do I Need?

The big and small of it is that size matters when it comes to choosing the right pot for your plant.

Too Big

If the container is too large for the plant, when rained on, or excessively watered, the soil will dry slowly causing the roots to stay damp and increasing the chances of root rot. Or with too little water, the large volume of soil will be too dry. Though there is evidence that doubling a pot size will encourage a 40% increase in growth in some plants, for most plants using a larger pot is a waste of nutrients, water, and space in your garden.

Too Small

However, this does not mean you should place your plant into a small pot. If the planter is too small for the plant, the plant could become root-bound and this can lead to slow or stunted growth. Trees and other types of large plants might fall over easily if they are in plant pots that are too small.

Another factor to consider is the effects of a perched water table.

What is a perched water table?

The phenomenon of the perched water table is key when deciding your planter shape and size. At the bottom of every pot, there is a layer of soil that will always be drenched in water, and will not be drained out by physical forces. This is because the force of gravity pulling water down is cancelled out by the soil pulling water up.

This formation water can only be evaporated or used by the plant. If the pot is too small for the plant, or the plant’s roots are too close to the perched water table, then this can have detrimental effects on the plant.

What is the optimum planter size?

Planters come in a variety of sizes. Our fiberglass planters range from 10 inches to 60 inches in pot diameter. Choosing the right pot size will depend on the plant and how many plants it is intended for.

For serious container gardening have a look at these guidelines:

Plant a 10-inch container with small fruits and small herbs:

1 strawberry plant

Small herbs, such as chives, parsley, mint, or sage

1 to 3 annuals

Plant a 14-inch container with leafy vegetables and larger herbs:

4 pea plants

1 leaf lettuce, spinach, cabbage or arugula

Larger herbs, such as rosemary or lavender

3 or 4 annuals

Plant a 16-inch container with larger fruit plants and small trees:

4 to 6 annuals

1 small shrub

1 dwarf citrus tree

1 bushy fruit tree, such as raspberry or blueberry

Plant an 18-inch container with larger vegetables and groups of herbs:

1 broccoli, cauliflower eggplant, tomato or pepper plant

mix of herbs

mix of annual flowers

Plant a 24-inch container with medium size trees and shrubs:

1 cucumber or summer squash

1 fig tree, dwarf peach tree, or nectarine tree

1 decorative shrub, such as a hydrangea

1 evergreen shrub

Plant a 30-inch container with the big boys:

1 orchard fruit tree such as apple, pear, cherryor pl um

1 sweet corn

1 pumpkin, rhubarb

What do I do when my plant gets too big?

 

As your plant grows you may have to re-pot it every year or two. For best results, choose a pot size that is 1-2” larger than the pot size before. If your container is currently 10” or bigger, then go for a pot that is 2-4” bigger.

Gardening lingo – Putting a plant into its first proper container or ‘transplanting’ from a smaller pot to a larger pot is called ‘potting up’.

Does plant pot shape matter?

 

Yes and no. Though the exact shape isn’t the biggest factor when it comes to container gardening performance, it does have an impact on your ability to arrange and look after your garden.

What are the different types of pots for plants?

Square containers

Square containers allow you to arrange your pots neatly and look great as decoration when lining a pathway or marking an entrance. When container gardening, a square arrangement can make watering easier with less gaps between planters for water to fall through.

A square pot also gives more volume for the same height, as well as more surface area for planting, than a round pot. This means there is more space to pack in potting soil and nutrients. Having this extra space is great if you want to grow rows of flowers or you are cultivating herbs for consumption.

Rectangular containers

Rectangular shapes are well-loved because of their practicality. They have a specific ‘front’ and ‘back’ or ‘left’ to ‘right’ which means you can plant an even row of flowers, vegetables, or even hedges!. The back is meant for drainage, so you should always remember to drill some holes in the bottom of it. This ensures proper drainage of water from the pot.

Round containers

This shape is most commonly used for herbs, vegetables and flowers that grow on smaller plants. Some people prefer them because they look cute and have a variety of different interior design applications.

On the other hand, they are not very practical for large plants as they tend to tip over easily and have no front or back, which makes it harder for plants to grow evenly together. Therefore a round planter is better for a single plant, or just a few plants.

If you do want a round design for something large like a tree, steer clear of round pots with tapered bases as these have more stability issues.

There is also an argument that round pots encourage the formation of circling roots, which cause absorption issues. This isn’t really an issue if you have the right size pot!

Tall Pots or Small Pots?

Based on the perched water table theory, tall pots are clearly the superior choice as the air to water ratio is the largest and enables better gas exchange. For a broad range of plants, a tall and wide, rather than a tall and narrow pot, will be the most suitable choice. This will accommodate most watering methods and needs.

River Rock Planter

However, there are exceptions. Succulents and cacti tend to thrive in shallow containers as they have one main taproot that goes deep into the pot and many thinner, shorter hair roots that stay close to the surface.

Here are a few tips on decorating with tall planters.

Does My Planter Need Holes For Drainage?

Drainage is king for potted plants. Selecting a container with holes at the bottom is always preferable to one without, this allows you some room to experiment with the watering needs of each individual plant. So, it is best not to use a container without a drainage hole unless you are very familiar with the plant and the amount of water it requires.

Drainage hole in clay pot

The drainage holes allow for excess water to drain out and reduce the chances of root rot. Place a saucer underneath the planter to hold water that leaks out.

We have a diversity of planters that suit any kind of project from home to commercial. This means that we have planter types for every kind of plant. Here is a short guide: