How Much Soil Does A Plant Need? ( A Detailed Guide)


Soil is the most important part of a plant growth and development process. It is a source of nutrition and helps our little friends to stay healthy, and If you are a new gardener or just decided to get the plants, then you may be wondering how much soil do plants need? And yes, it is a wise question to ask, soil amount does matter.

In this article, we will discuss how much soil your plant requires to stay healthy and happy. Additionally, it will teach you some tricks to measure the correct amount and depth.

So, let’s start digging.

Does Soil Amount Affect The Plant?

Soil amount that is given to the plant greatly affects its growth and healthy development.

Depending on the plant and what kind of soil it requires, some may need more, some may need less and some may even thrive without soil like Pothos.

The short answer to the question of how much do soil plants need is that there must be enough to support plant growth, It is essential for the plant to be elevated at the right height. This way, It will have access to light and air as much as possible.

Not only that, who wants the green beauty hidden in the deep pot? So yes, it is always better if the plant is elevated and with all other benefits, it shows its true beauty.

However, Did you know that there is more to that? For example, a potting plant, garden, raised bed garden, and vegetable garden requires a different amount of soil.

How Much Soil Does A Plant Need?

Potted plants must be able to show off their beauty and greatness as much as possible. You must avoid putting too much or too little soil in the pot.

Too much soil can retain moisture longer than the plant needs. Additionally, you will get muddy leaves and soil spilling over the edges.

You must also consider the height of the pot and should put enough so the soil does not spill out during watering. It is best if you put the soil on the level just below the rim of the planter.

Putting too little soil can cause health problems for the plants and plus, it is not really beautiful aesthetically.

Have you ever noticed? You put the perfect amount of soil in the pot and after watering, it just disappears somewhere and there is just a little bit of dirt left? The new soil is light, full of air, and fluffy. Therefore, when adding water, it sinks down several inches and compacts.

Important : Calculate the amount of soil you need for pots, raised or planter using this Soil Calculator

To avoid this, you can fill the pot or container with the soil, then add the water and let it sit, and then add some more soil.

Another thing you could do is to pour a small amount of water into the newly opened soil package and let it soak. This way, it will become damp and the soil will not compact in the pot.

Here is some common pot sizes and how much soil to put in them.

Pot Size9 cm
Pot Diameter Top9.0 cm / 3.5″
Pot Height 8.5 cm / 3″
Quantity0.54 liters
Pot Size1 Liter
Pot Diameter Top13.0 cm / 5″
Pot Height 11.0cm / 4″
Quantity1.46 liters
Pot Size 2 Liter
Pot Diameter Top 17.0 cm / 6.5″
Pot Height 13.0 cm / 5″
Quantity 2.95 Liter
Pot Size3 Liter
Pot Diameter Top 19.0cm 7.5″
Pot Height 15.0cm 6″
Quantity 4.25 Liters
Pot Size 4 Liter
Pot Diameter Top 20.0cm 8″
Pot Height16.5cm 6.5″
Quantity 5.2 Liters

A Trick To Fill Up Big Planters

If you have a large pot or container, it will require more soil and that can lead to additional costs.

What you can do in that situation is to fill the bottom of the planter with additional materials such as small rocks or empty water bottles.

These materials will take up space and will require less soil. However, make sure that you put enough dirt to support and sustain the plant.

If your pot is not very large, it is recommended not to put anything in the bottom. This way, you will only rob the plant and not give it enough nutrients. This technique works only on large containers and extra large planters.

How Much Soil Do Plants Need In The Garden?

If you just decided to start gardening or want to redo the existing one, you may be wondering how much soil will be needed.

In order to get the correct amount that is needed, you can do some calculations.

First of all, start with measuring the area that you are planning to use for the garden. Also note whether you are going to do a square, rectangular, or another type of garden.

A squared garden is the easiest to calculate. The formula that will tell you approximately how much soil you will need is A X B X Depth = M3.

To say in simpler words, you can multiply the area by its depth, and this way, you will get the total quantity of soil that is required. It is always better to convert the measurements into one unit, for example, meters or centimeters.

There are many online calculators that you can use to do the measurements, or you can ask a professional planter for advice.

If you plan to have flowers that have a large bulb, the bulbs need to be planted a minimum of 8 inches deep in the soil and require at least 6 more inches in the bottom.

How Much Soil Do Plants Need In A Raised Bed Garden?

In most cases, the height of a raised bed in the garden depends on the preferences. Many things need to be considered too, such as the soil beneath the bed, what are the requirements of depth for a specific plant that you are planning to have, the amount of bending over that you want, and rooting requirements.

Raised bed gardens have an open bottom and this gives root space and access to the nutrients that are in the soil below ground level.

It is always better to double-dig the soil before putting the bed on top. Double digging can be done to two shovel blade lengths.

This is approximately 24 inches deep. By doing so, rocks and debris will be removed and the roots will grow freely.

After double-digging, the peat moss can be added to make the soil lighter and since it is acidic, it is always good to add something that will balance pH.

The soil on the raised bed can be filled from a few inches of the top. After putting the soil, the fertilized and compost are added.

The most popular height for raised bed gardens is 11 inches. If you will up the raised bed garden with the soil on 11 inches, then it will provide your plants with good drainage. It is also recommended to have additional 12 inches of natural soil below the bed.

How Much Soil Do Vegetables Need?

If you want to have a vegetable garden, first of all, you will have to check out the growth and characteristics of each plant you are planning to have.

The top of the soil, mostly the top 6 inches, is the main nutrient source that is needed for the vegetables.

This is so because the roots of the vegetables, in most cases, are showing in relatively shallow depth.

For example tomatoes, carrots, and peppers have deeper roots and will require soil that is deeper and rich in nutrients, a good amount of depth can be 12 inches.

If you want to have cabbage, you must make the soil at least 10 inches deep.

For different vegetables, soil depth requirements vary. Commonly, the raised beds for vegetables are 8 to 12 inches tall. Sometimes, the sides of the vegetable raised beds are three inches and higher.

The 8-12 inches of depth is like a rule of thumb and can be considered accurate no matter if you have an elevated bed or planter box.

The Verdict On How Much Soil Plants Need.

Even experienced gardeners struggle on deciding how much soil they need for their plants. Having too much or too little can change many things and may not be beneficial.

Knowing how much soil plants need is a very important and a success factor in the health and well-being of your plants.

Providing with enough soil means that your green friends have enough nutrients and support. Therefore, it will thrive and will proudly be beautiful. 

Peride Beradze
Peride is an avid planter, Tour Manager and freelance writer. She is a plant collector who mainly focuses on succulents. She loves studying cultures, traveling and learning new languages.

Calculate the amount of soil you need for pots, raised beds or planter with the help of this easy to use Soil Calculator