reading time: 5 Protocol
IN THIS ARTICLECalculate the volume of the pot|How to use potting soil|Which bag sizes?|Our decisions
How much potting soil mix do I need for my tub garden? It's one of those questions I ask myself every spring, and every spring I follow the same process to solve it. If you use standard container/pot sizes, the calculation is easy. For specific containers/pots I use an online calculator to make it easier.
There are two simple methods you can use to calculate how much potting soil you need. Use our potted plant volume chart or an online tool. How simple.
Figuring out how much potting mix you need is really a very simple process. I'll walk you through the process that I follow below.
TIP We recommend Multipurpose Potting Soil as the best selling product below.
How to calculate soil volume for standard pots
There is a standard range of potted plants in standard sizes. These are round and have specific dimensions. I have compiled a list of standard container/pot sizes and the estimated amount of potting soil needed to fill each size. Each container/pot is measured internally, so we use internal measurements to estimate volume.
Volume table for standard round containers or pots
10 cm pots require about 0.5 liters of potting soil.
15cm pots use approximately 1.5 liters (1.5 liters) of potting soil.
20 cm pots require about 4 liters of potting soil.
25cm pots require approximately 7 liters (7 liters) of potting soil.
30 cm pots need about 11 liters of potting soil.
35 cm pots need about 17 liters of potting soil.
How to calculate the volume of a square or rectangular pot
If you have square or rectangular containers/pots I recommend using the online volume tool described in the next paragraph. It's that quick and easy. However, if you want to calculate the volume manually, use the following steps.
- Measure the inside length, width, and height in inches as these easily convert to quarts, gallons, or liters.
- Multiply the length by the width by the height to get the total volume in inches. For example 10cm*10cm*10cm=1000cm3
- You can use Google to convert any volume measurement to another. For example 1000cm3equals 1.06 US quarts.
Record the total volume of each container or pot you measured. Count the number of containers/jars you have of each size and multiply the volume of that size by the number of containers/jars you have. For example, 4 by 8 inch pots equals 16 liters (16 liters) of potting soil. Finally, add up your totals.
TIP Always add a little more volume than the appreciated potting soil. Allows spillage.
How to calculate the volume of soil for non-standard pots
The method I use for non-standard pots is very simple, use an online calculator. There are a lot of great tools out there and this is the one I use."omni calculator🇧🇷 It's totally free, no login required and easy to use.
Before clicking on the calculator link you need to measure the inside height and inside diameter of your container/pot if it is round. Square or rectangular containers you need within length, width and height. It should be the inside measurement as this is the space we want to fill with potting soil. You can use the calculator to define the shape you want.
You also need to choose the unit of measure you want to use. You can use inches or centimeters depending on what you are comfortable with. Then you can select the unit of measure you will use to return the volume of the potting soil, e.g. B. quarts, gallons, liters. It's all there.
You'll end up with plenty of potting soil to fill your container or pot.
So use a mix of just for glasses
Unlike garden soil, potting soil is an all-in-one plant growing medium, so nothing needs to be added to enhance it. General purpose potting mixes are usually sterilized (heat treated) to eliminate all living organisms, seeds, insects and plant diseases. They are made by mixing compost, peat, humus and pumice. Each brand has its own recipes and strains, some even for specific plant species.
TIP Always clean your container or pot before use. This will help prevent unwanted bacteria in your potting soil. You can use a simple household detergent and a stiff bristled brush.
Take a clean pot and sow your plant with a full root ball. Put a small amount of potting soil at the bottom of your new container/pot. Add enough potting soil so that the top of the root ball is about 1/2 inch (1.5 cm) from the inside of the pot (once the plant is seated). Place the seedling in the center of its container/pot and fill in the space around the sides of the root ball with potting compost until it is just covered. Firm this by hand and then top up as needed. Finally, water the potting soil well to help the plant settle into its new home.
TIP Always wear gardening gloves when handling potting soil, this protects you from bacteria that can live in the soil mix.
What size bag of potting soil should I buy?
Depending on where you live, potting soil comes in bags that are measured in quarts/cubic feet or liters. In the US, common sizes are 4, 8, and 16 quarts (roughly 4.8 and 16 liters), then 1 and 2 cubic feet (30 or 60 liters).
After you total the total amount of potting mix you need, find the brand and amount you need. I also rounded up my volume, better too much than too little. After all, we are dealing with estimates.
The last thing to consider is where are you going to keep your bags of potting mix, the unused portion? If space is an issue, choose a bag size that easily fits in the available storage space. Remember, the bigger the bag, the heavier it is. Smaller bags are not only easier to store, but also easier to manage!
TIPI recommends that you purchase 1 additional bag of potting mix, enough to fill your containers/pots after the potting soil has settled.
Conclusion
Potting mix is a wonderful thing. It's rich, clean, beautiful soil ready to go and ensure you have a healthy plant. We've outlined two techniques to help you estimate the amount of potting soil you'll likely need. You want to fill your containers or jars and have some left over. Just a little. I hope this article has given you the information you need.
Our decisions
Quality consumables make all the difference in plant performance. This is our pick of the best container stock so you can watch your plants thrive.
As an Amazon Associate, I earn from qualifying purchases. Clicking on a link to any of the products listed below will cost you nothing unless you decide to make a purchase. If you decide to make a purchase, we receive a small commission that helps offset the cost of our site. More information can be found in our detailed “Disclosure of Affiliates“.
The best soil for all-purpose pots.
The best organic potting soil for all purposes.
TIED TOGETHERCalculator for cups only
FAQs
How much potting soil do I need for pots? ›
Fill the container completely with soil, leaving some space between the top of the soil and the top of the pot (this is sometimes referred to as head space). In large container gardens, you can leave up to 2 inches;in smaller pots you might only leave ½ inch.
How many 3 gallon pots will a bag of soil fill? ›| Size | Gallons | Bags of Soil (1.5 Cubic Feet) |
|---|---|---|
| 1 Gallon | 1.00 | 11.2 Pots Per Bag |
| 2 Gallon | 1.84 | 6.1 Pots Per Bag |
| 3 Gallon | 3.37 | 3.3 Pots Per Bag |
| 5 Gallon | 5.14 | 2.2 Pots Per Bag |
How much soil? For a 4x8–foot raised bed with a 10” height, about 1 cubic yard of soil is needed. For a 4x8-foot raised bed with a 6” height, using Mel's Mix: about 5 cubic feet each of compost, peat moss, and vermiculite is needed.
How many bags of potting soil do I need for 1 yard? ›The amount of soil to fill a 5-gallon pot or bucket is approximately 0.7 cubic feet. If your soil comes in bags of 2 cu. ft. then you should be able to fill about three 5-gallon pots.
How much soil do I need for 10 pots? ›Based on their top diameters, here are the soil amounts required to fill the most common sizes of round pots: 8 inch (20 centimeter) – 1 gallon (4 quarts or 3.8 liters) – 0.15 cubic foot. 10 inch (25 centimeter) – 3 gallons (12 quarts or 11 liters) – 0.46 cubic foot.
Do plants grow bigger in bigger pots? ›Summary: Plant scientists have imaged and analyzed, for the first time, how a potted plant's roots are arranged in the soil as the plant develops. In this study,biologists also found that doubling plant pot size makes plants grow over 40 percent larger.
Do you pack soil when planting in pots? ›Pour a layer of fresh potting soil into the empty planter and pack it down, removing any air pockets. If your planter doesn't have a drainage hole, layer the bottom with lava rocks or similar (rocks, gravel, etc.) before adding the potting mix.
How many cubic feet are in a 40 lb bag of potting soil? ›A: Using the estimate of a 40# bag has a volume of 1 cubic foot. The volume would be 15 cubic feet (5ft x 3ft x 12/12 ft) so we would estimate around 15 bags would be required to fill this volume.
How many quarts of potting soil does it take to fill a 5 gallon bucket? ›5 gallon = 14 dry quarts (15.4L) = 0.54 cu. ft.
How many pots will a bag of soil fill? ›
| Pot type & size | Approximate soil volume of pot*(dry quarts*) | 20-qt bag |
|---|---|---|
| 12 inch | 5.5 | 3½ |
| 14 inch | 8.4 | 2½ |
| 16 inch | 12.0 | ¾ |
| 18 inch | 18.8 | 1 |
Potting Mix is formulated to feed the soil for plants growing in indoor and outdoor containers, while Raised Bed Soil with its slightly larger particle size, has versatile uses for both larger containers and raised bed gardening.
Is raised bed soil better than potting soil? ›Soil taken from your yard or a garden bed is too dense to use in a pot or raised bed. Instead, for containers, you'll want to use potting mix (also called potting soil), a lightweight and fluffy alternative. For raised beds, you'll want to use a blend of potting mix and garden soil.
How many bags of soil do I need for a 4x4 raised bed? ›It usually takes about two to three bags of purchased fertile mix (1.5 cubic feet each) to cover the bed surface to a depth of 2 inches.
Is it cheaper to mix your own potting soil? ›Making your own potting mix has several benefits… Cheaper than buying a premade mix – Commercially produced mixes are expensive to buy, so making your own will save you money. The ingredients you need are inexpensive, and you can use them in many different homemade potting mix recipes.
Will 2 yards of soil fit in a pickup? ›Full-size Pickup Trucks: Can usually handle 2 cubic yards of soil, 2-3 cubic yards of mulch, and 1 cubic yard of stone or gravel. Small Pickups and Trailers: Can usually handle 1 cubic yard of soil to maybe 1½ of mulch.
How many 40 lb bags of soil make a yard? ›A 40lb bag of topsoil yields 0.75 cubic feet or 0.028 cubic yard or 0.02 short tons, as 1 cubic yard is equal as 27 cubic feet, so number of bags of 40lb of topsoil in a yard = 27/0.75 = 36 bags, so, there are 36 bags of 40 lb of topsoil in a cubic yard.
How many cubic feet are in a 50 quart bag of potting soil? ›A: 25.71 dry quarts = 1 cubic foot. This 50 quart bag of Miracle-Gro Potting Mix would be 1.9 cubic feet.
How many plants can you put in a 5 gallon bucket? ›Not only do the buckets hold the perfect amount of soil for roots to thrive, but they also take up minimal room, so they don't crowd a patio or deck. One 5 gallon bucket can be home to one vegetable plant or two, or three small herbs.
How big is a 5 gallon potting container? ›Dimensions: 12″ wide x 11″ tall.
How deep should potting soil be? ›
A depth of 8 to 12 inches may be enough, unless the soil does not drain well; dig 12 to 18 inches for vegetable plants. You can edge the raised bed with landscape timbers, bricks, metal strips or simply leave it open. Choose well-draining soil that retains moisture but will not dry out.
Are plastic pots good for plants? ›Unlike clay, plastic is non-porous, which means it doesn't let in or out as much moisture or oxygen. As a result, plastic planters retain moisture for nearly double the time of clay planters. That means if you're the type that tends to forget to water your plants, plastic is probably a safer option than clay.
How do I know when it's time to repot? ›Signs It's Time to Repot
One of the easiest ways to tell that a plant needs repotting is to check and see if the roots are growing out of the drainage hole of the pot. If so, this is an indication that the roots have run out of room and your plant needs a larger pot.
You don't need to fill a large planter with soil (unless you want to and can afford it). There are plenty of other materials you can use that work well and ensure the potted plant or tree continues to grow and thrive.
How do I know if my soil is too packed? ›- Pooling or puddling of water in low areas.
- Water running right off the soil in high areas.
- Stunted growth of plants.
- Shallow rooting of trees.
- Bare areas where even weeds or grass will not grow.
- Areas too hard to drive a shovel or trowel in the soil.
Lining Pots
Always buy more plastic liner than you think you need. Push it well down into the pot, and use a pair of scissors to cut out drainage holes in the bottom. Then place a layer of pebbles or stones in the base, and fill up with potting mix, the weight of which will push the liner further down.
Consider a ½ cubic foot bag of stone or soil weighs about 50 lbs and will cover 2 square feet at 3" deep. A bag of hardwood or cedar bark contains about 1 cubic foot of material, enough to cover about 4 square feet at 3" deep. If you have large areas you probably need bulk.
How many bags of soil do I need for a 4x8? ›For a 4×8 raised garden bed that is 8 inches high, you will need 21.44 cubic feet of soil or 15 bags of soil. 15 bags of soil is needed if each bag of soil contains 1.5 cubic feet of soil. This figure is for the total soil needed to fill your raised garden bed.
How much does 1 yard of soil cover? ›When using the soil for top dressing your lawn, a cubic yard will cover 1296 sq. ft. at a depth of 1/4 inches.
How many quarts are in a bag of 1 cubic foot potting soil? ›Helpful? A: There are 25.71 quarts in 1 cubic foot dry weight potting soil.
Is a 5 gallon bucket really 5 gallons? ›
The majority of 5 gallon buckets do hold 5 gallons of water. However, depending on where you purchase your 5 gallon bucket, there can be some uncertainty as to where the 5 gallon mark is.
How many gallons is 2 cubic feet of soil? ›There are 12.86 US dry gallons in 2 cubic feet.
How long will a bag of potting soil last? ›How Long Can You Store Potting Soil? Opened bags of new potting soil can retain quality for around 6 to 12 months. For unopened and unused potting soil, you can store it for about a year or two before it goes bad.
Should I Buy potting mix or potting soil? ›Potting soil vs. potting mix: Though these terms are used interchangeably, there is a difference. Potting soil may or may not contain soil, while potting mix is strictly a soilless medium. Potting mix is sterile, which makes it safer for plants because it doesn't contain pathogens such as fungus or other diseases.
Is it OK to mix potting soil with garden soil? ›Potting soil can be mixed with garden soil for particular cases such as raised beds, but it's not a good mix for containers. Learn more about these different types of soil and how to use them in various types of gardens.
Do I need potting soil or potting mix? ›Potting mixes are suitable for potted plants, while potting soils are good for outdoor plants and landscaping. However, most potting mixes and soils are harmful to your plants and the environment. But not Rosy. So if you're looking for a high-quality, sustainable soil mix, you should try Rosy's Indoor Potting Mix.
Can you reuse soil from last year? ›It's generally fine to reuse potting soil if whatever you were growing in it was healthy. If you did notice pests or diseases on your plants, it's best to sterilize the mix to avoid infecting next year's plants. First, remove any roots, grubs, leaves, and other debris from the old potting soil.
Do I really need potting soil? ›Potting soil provides the right structure and nutrients for plants to grow—ideal mixes are usually made up of about 50% solid materials (45% mineral particles like sand, silt and clay and 5% organic matter/compost), 25% water and 25% air (oxygen). So that's why you should use potting soil in pots.
Can I use Miracle-Gro garden soil in pots? ›Using straight garden soil in your containers is not a good idea. Garden soil on its own lacks the drainage, aeration, moisture control and nutrients necessary to successfully grow plants in containers. When used by itself, garden soil or topsoil in containers becomes so compacted that water cannot drain.
What is the cheapest way to fill raised beds? ›Logs buried in the raised bed are beneficial because you won't need much soil. That's why using large logs can be one effective organic material for filling raised beds cheaply. You can find grass clippings, twigs, branches, logs, and other rotting materials. Then, place them deep in the soil.
How many bags is 4 yards of soil? ›
| Cubic Yards | 1 Cubic Foot Sized Bags | 4 Cubic Foot Sized Bags |
|---|---|---|
| 3 | 81 | 20 |
| 4 | 108 | 27 |
| 5 | 135 | 34 |
| 6 | 162 | 41 |
For example, if you have a length of 5 feet, a width of 4 feet and a depth of 2 feet, the volume would be 40 cubic feet (5 x 4 x 2 = 40). This is the amount of dirt you will need to fill your raised planter box. This would equal 20 bags of soil sold in bags containing 2 cubic feet of dirt each.
How many cubic feet are in a 40 lb bag of soil? ›All Purpose Top Soil, 40 lb. Bag / 0.75 Cubic Feet.
How many cubic feet of potting soil do I need for a 5 gallon bucket? ›A good rule of thumb, the typical capacity of a 5-gallon bucket is 16 quarts of dry soil and dirt and. 7 cubic feet of earth.
How much does a 40 lb bag of soil cover? ›One 40 lb. bag covers up to 4.5 sq. ft. at a 2-inch depth.
How much potting soil do I need for a 25 gallon bag? ›24 inch pot (61 cm) = 25 gallon (95L) = 3.8 cu. ft. 30 inch pot (76 cm) = 30 gallon (114L) = 4.6 cu.
How many cubic feet are in a bag of potting soil? ›Potting Soil For Containers
Typically, potting soil is sold in the following sizes: 8 quarts, 12 quarts, 1 cubic foot, 1.5 cubic feet, 2 cubic feet, and 3 cubic feet.