How Much Potting Soil Do I Need For My Container Gardening?

When you’re ready to start gardening, especially container gardening, one of the first questions you’ll need answered, other than which plants to start off with, is what size container or pots should I use and how much potting soil do I need.

Containers and planting pots come in a variety of sizes, so, it’s important to know the right size to choose for your plants. Choosing the perfect size is not hard, once you know what you need to look for in a container.

Gardening 101: Choosing The Right Container and Pot Sizes And How Much Soil Do I Need?

But, we’ll go over everything you’ll need to know when choosing a container as well as how much soil you’ll need for your containers or raised garden beds.

Do You Need A New Container Or Growing Pot?

Yes, you do! The first step in plant parenthood is transplanting. This is why you need a new container or a growing pot. Unless you have empty planters available in different sizes.

Keep in mind, too, that there are plenty of things you probably have at home right now you can use to transplant your seedlings. For instance an old purse, I have Thai basil in a handbag and a beautiful arrangement my DIL made for me in a hanging purse that hangs on the handrail of my front porch.

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You can use a wastebasket, 5 gallon bucket, canvas bags, I have many of my plants in a wading pool in Walmart bags, you can use kitchen containers (as long as they are the right size and you clean them well) such as dishwasher plastic containers, coffee, or margarine tubs, Rubbermaid storage containers, you can even plant directly in your potting soil or potting mix bags (if the root system of your chosen plant doesn’t need very deep soil ).

Use your imagination and also be sure to clean them out well before using them.

Yes. It’s good for your young seedlings to be able to stretch out their roots and deepen their root system.

When you buy a new plant or seedling from the nursery, it’s likely it has already overgrown its temporary plastic container. They may look full and fresh once you get them, but, if you don’t properly transplant young plants, they’ll likely die if left in the plastic pot from the nursery.

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Do I Always Need To Repot My Plants?

When you’re shopping for seedlings at the nursery you’ll see the older ones that are looking a little less healthy – that’s because they need room to grow and they have outgrown their small container.

Transplanting your plants gives them a fresh media to grow in. A new container allows the plant to grow larger and to extend it’s root system which makes it a healthier plant and will in turn make it produce better.

It allows them more room so the roots of your plants can stretch out and gain more nutrients and continue flourishing.

Ok, now that we have determined that we have to transplant our new plants, we have a few more issues to deal with before we get down to answering the question “How much potting soil do I need?.

Does Size Matter?

Yes, it does. The size you hear or read at the nursery does not refer to the plant size. Instead, it refers to the diameter of the pot.

So when we see a 6” plant at the nursery, it is referring to the plant being grown in a 6” diameter pot at the time.

Do I Need A Pot Or Container With Drainage?

Yes. It is recommended to select a pot or container with drainage. When the soil becomes too wet or has too much water and there is no way for the excess water to drain out, the plants can drown and even die.

So, it’s important to get garden containers with proper drainage to keep your plants happy and healthy.

How To Know The Right Size

Before we can answer the question: How Much Potting Soil Do I Need?, we need to know which size container we’ll be working with to determine the correct volume of soil, potting soil, or potting mix we need.

It can be so confusing when mulch, soils, and mixes are measured by cubic yards, cubic feet, square feet, quarts – all the differing measurements for the same thing. Why can’t all the companies get together and decide on one cohesive measurement for all soil or mulch?

If you use a pot that is too large for your plant, the soil can dry out quickly and you’ll find yourself watering it often. Meanwhile, if the plant is too big for the pot, it has the tendency to tip over, and also to become root-bound.

Plants need room to grow deep roots and spread their roots out, so give them enough room for that, but, not so much as to swallow the plant whole.

In a pot that is too small, the soil can dry quickly, as well. Not only do you need to water the plant frequently, it can also cause the plant to become root-bound and limit its growth.

If the plant is in a 10″ container or smaller when choosing a pot, container, planter box, or raised garden bed, choose something that is 1 to 2 cubic inches larger than the current size of the raised garden beds, pot, or container the plant is in.

If the current pot or container is larger than 10”, choose something that is 2 to 4 inches larger in diameter.

Decide On Which Material To Use

The most common materials for pots and containers for container gardening are plastic, terracotta, or clay.

Plastic pots are colorful. They are lightweight and are the least expensive. These pots can also retain moisture, so, you need to water less frequently. They are ideal to use for hanging plants.

Neo Sci 6” Plastic Flower Pot

Zicome Colorful Plastic Plant Pots with Saucers

Terracotta pots are much heavier, but, they often come in beautiful patterns. They also cost more than plastic containers.

These pots are porous, so, you’ll need to water the plants more frequently. Terracotta pots are ideal for succulents, bromeliads, orchids, and indoor plants.

Bloem 6″ Terra Pot Planter

Bloem 8″ Peppercorn Terra Pot Planter

Amount Of Soil To Use

Now, down to the original question, “How Much Potting Soil Do I Need?”. How much soil you need to use depends on the size of your pot and type of pot – regular or hanging. It can be so hard trying to determine how many bags of soil to buy when you’re standing in the store staring at it all.

However, we have done the math for you! Here are some guidelines:

Regular Pots

• 4 inch pot (10 cm) = 1 pint (0.5L)
• 5-6 inch pot (13-15 cm) = 1 quart (1L) = 0.03 cu. ft.
• 7-8 inch pot (18-20 cm) = 1 gallon (4L) = 0.15 cu. ft.
• 8.5 inch pot (22 cm) = 2 gallon (7.5L) = 0.3 cu. ft.
• 10 inch pot (25 cm) = 3 gallon (11L) = 0.46 cu. ft.
• 12 inch pot (30 cm) = 5 gallon (19L) = 0.77 cu. ft.
• 14 inch pot (36 cm) = 7 gallon (26L) = 1 cu. ft.
• 16 inch pot (41 cm) = 10 gallon (38L) = 1.5 cu. ft.
• 18 inch pot (46 cm) = 15 gallon (57L) = 2.3 cu. ft.
• 24 inch pot (61 cm) = 25 gallon (95L) = 3.8 cu. ft.
• 30 inch pot (76 cm) = 30 gallon (114L) = 4.6 cu. ft.

Hanging Baskets

• 10 inch (25 cm) = 5.5 dry quarts (6L) = 0.21 cu. ft.
• 12 inch (30 cm) = 7.9 dry quarts (8.4L) = 0.3 cu. ft.
• 14 inch (36 cm) = 13.9 dry quarts (15.3L) = 0.5 cu. ft.

Types of soil

• Clay Soil: the best way to amend this soil is to add peat moss but you need to be careful because of the moisture retention. Both clay and peat hold moisture, so when adding it, be sure it’s just one part peat. You can also use coconut coir as one of your soil amendments.
• Sandy soil: is’s a good idea in vegetable gardens because of the good water drainage it provides.
• Silt soil: this is a good and common soil for gardening. Lots of different types of plants do well in silty soil.

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Live Plants As Decoration

Most plants won’t thrive in standing water, so, it’s a must to have a drainage hole at the bottom of the pot. This allows water out and air in for your plants to grow.

You can still use a pot without drainage holes, especially if you are using it for decorative purposes. Use a cachepot which holds the pot that the plant is growing in.

All you need to do is to place a plastic or terracotta pot inside the container. A cachepot does not need any drainage holes. However, it should be large enough to fit a saucer that fits the growing pot.

Abigails Round Cachepot

Napa Home & Garden Concrete Pipe Cachepot

Ceramic Striped Graphic Geometric Cachepot

Before you start expanding your container garden, choosing the right pots or containers as well as the right amount of potting soil for your plant is a must.

You’ll need to determine if you’re going for practical or decorative, diy, frugal, or upscale, you’ll need to make sure it’s the right size for the plant and the place where it will live.

Another thing to be mindful of is how heavy it is when filled with wet soil, a large plant, and if you have any fillers in it such as rocks

Different Types of fillers

• Wood chips
• Pine bark
• Pine needles
• Bark chips

Many times you’ll want to move it for watering or better sunlight, pruning, harvesting – whatever, you’ll want to make sure you can pick it up.

There are beautiful, decorative planters that are heavy to begin with, and then you add fillers, soil, water, a plant – as the plant grows and fruits, it’s only going to get heavier – just keep that in mind, as well.

Also, with decorative containers they often don’t have drainage holes, so be aware of that, and if they DO have drainage holes, make sure you have something to place under it to catch the runoff, especially if it will be indoors.

What Vegetables Can I Grow In A Container Garden?

Beans
Brussels Sprouts
Cabbage
Carrots
Chilies
Collard Greens
Cucumber
Eggplant
Garlic
Greens
Kale
Okra
Onion
Peas
Peppers
Radishes
Rhubarb
Spinach
Squash
Swiss Chard
Tomatoes
Zucchini
To name a few…

Which do you prefer: A Plastic Pot or a Terracotta? I would love to hear what you think! Also what do you use as a blended soil mix for your plants? Do you use your own homemade compost or do you buy compost?

I hope the charts above help you with your “How Much Potting Soil Do I Need?” question.

You can also find gardening products I use in my videos here <---

I now have an Amazon Influencer’s storefront. I put the products I use, in my posts and Youtube Gardening videos, there. Shopping there is free and the site gets a percentage of sales. Thanks!

You can go to my storefront using this secure link <----

If you need seeds, this is the company I use <--- and if you use code: farmer1 at checkout, you'll get 10% off your order!

You can also find gardening products I use in my videos here <---

I now have an Amazon Influencer’s storefront. I put the products I use, in my posts and Youtube Gardening videos, there. Shopping there is free and the site gets a percentage of sales. Thanks!

You can go to my storefront using this secure link <----

If you need seeds, this is the company I use <--- and if you use code: farmer1 at checkout, you'll get 10% off your order!