How Many Pots Can You Fill with a Bag of Soil?

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containers filled with lettuce, herbs, and flowers

Look at the sizes of your containers to determine the size of the bag(s) you’ll need to buy.

For example, a 20-quart bag fills two 12-inch standard clay pots, or you can fill one 14-inch basket and still have enough to fill half of another 14-inch basket. To follow this example, find the pot sizes in the column on the left, and then follow the line to the right to the shaded boxes.


SIZE OF BAG AND APPROXIMATE NUMBER OF POTS THAT IT FILLS:

Pot type & size Approximate soil volume of pot*(dry quarts*) 10-qt bag 20-qt bag 32-qt bag 40-qt bag 64-qt bag
STANDARD CLAY POTS
8 ¼ inch 3.6 3 9 11 18
10 ¼ inch 6.9 3 6 9
12 inch 10.7 1 2 3 4 6
14 inch 15.3 ½ 2
STRAWBERRY JAR 5 gallon 14 ¾ 3
HANGING BASKETS
10 inch 5.5 2 7 11½
12 inch 7.9 4 5 8
14 inch 13.9 ¾ 3
BOWLS
8 inch 1.9 5 10½ 17 21 34
10 inch 3.7 11 17
12 inch 5.5 11½
14 inch 8.4
16 inch 12.0 ¾ ¾
18 inch 18.8 ½ 1 2
21 ¾ inch 31.2 ¼ ½ 1 2
OVAL PLANTERS
12 inch 3.8 10½ 16¾
16 inch 7.3
20 inch 9.4 1 2
SQUARE PLANTERS
12 inch 11.2 1 ¾
15 inch 23.0 ½ 1
WINDOW BOXES
24 inch 11.7 1
30 inch 15.6 ½ 2 4
36 inch 19.7 ½ 1 2 3¼ 

 

 

This isn’t perfect, but it beats a wild guess.

When you buy potting soil, are you just guessing at how much you need? We hope this table has given you a way to figure how much to buy. However,  these figures are approximate. Here’s why:

There are very few standards regarding container sizes and volumes. To make it even more confusing, containers that do list volume typically measure using liquid quarts. Of course, potting soil is not a liquid, so the bags contain dry quarts, which are about 1 1/8 liquid quarts. None of this is really important to your success. We’re just explaining so that you will understand why the numbers on this table are approximate.

Nor do these figures account for any packing down of the soil (the taller the container, the greater the compression). Compression can cause you to need 15% to 20% more soil. On the flip side, the soil that comes with your plants (around the roots) will add volume.

Do take notes about your own pots if you have containers that you use over and over again. That is the only way to know exactly how much to buy.

Store leftover soil in a dry place, perhaps in a clean plastic tub or garbage can, until next time.

Adapted from soil volume tables from Conrad Fafard, Inc., makers of commercial and home garden potting mixes.

8 thoughts on “How Many Pots Can You Fill with a Bag of Soil?

    • Great question Grace!
      Soil is often forgot about…and plants do start at the roots. A good potting mix is nice and fluffy, not heavy like a garden soil. Good potting mixes usually contain ingredients such as spagnum peat moss, vermicultite, perlite, or aged pine bark. You can read all about good potting mixes here. There are a lot of good brands available in store garden centers.

  1. Not helpful. Bonnie potting mix comes in a 9cu.ft.bag. How does that translate into the quarts you show on your chart? When starting seeds, the pots are much smaller than the 8″ listed on this char.

    • Hi Jane,
      Are you using our Bonnie Plants soil that comes in a large bale? That is for our own growers and not usually available to the public. As we sell vegetable and herb plants — not seeds– we don’t have articles in this site on starting seed. All tips and advice are for using our 4- and 6-pack plants or those in 5″ biodegradable pots or larger. So, these container sizes are for plants that have had a healthy head start. ~Mary Beth, Bonnie Plants

  2. Web page not useful to me, as I was looking for
    the volume of 4″ , 5″, and 1 gal black nursery containers.

    • Hi Gerry,
      Let’s see if we can help you. It sounds like we provide the reverse information of what you seek, though many gardeners want to know how far one bag of soil will “go.” If you are looking for the volume of a 4″ pot, it honestly depends on the pot you have. Oddly, one gallon pots aren’t always one gallon in volume, and 4″ pots can be tall or short but 4″ across. This site, for instance, is one that I found during a quick search that shows you a trade gallon (3 quarts) vs a full gallon. Hope that helps you along your search. ~Mary Beth, Bonnie Plants

  3. Every year I try to grow tomatoes in clay pots. I put new bags of soil in them every year, can I reuse this soil and put some type of nutrient in the soil? If so what type of nutrient.

    • Hi Noreen,
      It’s smart to use new bags of soil each season for containers. We do not recommend reusing this soil. You were on the right track! Tomatoes in clay pots also need a watchful eye for watering (don’t let the pots dry out) and they love liquid feed, like our natural plant food. Let us know how it grows! ~Mary Beth, Bonnie Plants

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