Planter & Pot Soil Calculator | How Many Liters and Bags? Pot Size Chart and Plant Count (Home Gardening)
The Planter & Pot Soil Calculator works out the volume of soil (L) from a pot's size number (1 go = 3cm diameter) and shape (standard, deep, shallow, or square), standard and deep 65cm planters, or the dimensions of a garden bed or raised bed, after subtracting the water space and drainage stones. For commercial potting soil or mixes such as "7 parts akadama : 3 parts leaf mold", it then tells you how many liters of each material and how many 14L or 25L bags to buy. You can calculate pots and planters of different sizes together, and it also gives the amount of drainage stones and the grams (and tablespoons) of dolomite lime and base fertilizer to mix in. For 32 crops including mini tomatoes, eggplant, cucumber, strawberries, leaf lettuce, komatsuna, and basil, it shows how many plants fit in your container from the plant spacing and the soil each plant needs, with a top-view diagram. It also gives the weight of soil after watering and the weight per m² when lined up on a balcony (compared with the typical residential floor load guideline of 180kg/m²), plus quick-reference charts of soil volume by pot size number and planter.
Containers (pots, planters, beds)
Enter the containers you will use and how many. You can calculate pots and planters of different sizes together (up to 12 types).
1. Planter Deep 65cm (for vegetables)
Each: soil 27.2L · drainage stones 3.2L (3cm) · water space 2.5cm · depth 26cm
2. Size 7 pot (21cm)
Each: soil 3.2L · drainage stones 0.32L (2cm) · water space 2cm · depth 18cm
Soil Amount & Bags to Buy
Choose a mix to see how many liters and bags of each material you need.
Soil amount (total for 3 containers)
33.5L
Drainage stones
3.8L
Dry weight (to carry home)
about 17kg
Soil mix
Many already contain base fertilizer and lime, so you can use it straight from the bag. The easiest option
Buy extra (to allow for shrinkage after mixing and settling after watering)
| Material | Amount needed | Bag size | Bags to buy |
|---|---|---|---|
| Commercial potting soil (for vegetables & flowers) | 36.9L | 2 bags |
Most commercial potting soils already contain dolomite lime and base fertilizer. Check the bag for labels such as "with base fertilizer" or "ready to use".
| Container | Count | Soil each | Drainage stones | Total soil |
|---|---|---|---|---|
| Planter Deep 65cm (for vegetables) | 1 | 27.2L | 3.2L | 27.2L |
| Size 7 pot (21cm) | 2 | 3.2L | 0.32L | 6.4L |
ABOUT
About Planter & Pot Soil Calculator | How Many Liters and Bags? Pot Size Chart and Plant Count (Home Gardening)
The Planter & Pot Soil Calculator works out the volume of soil (L) from a pot's size number (1 go = about 3cm diameter) and shape, standard and deep 65cm planters, or the dimensions of a garden bed or raised bed, after subtracting the water space and drainage stones. For commercial potting soil or mixes such as "7 parts akadama : 3 parts leaf mold", it tells you how many liters and bags of each material to buy. You can calculate pots and planters of different sizes together, and it also gives the amount of drainage stones and the grams of dolomite lime and base fertilizer. In addition, for 32 crops including mini tomatoes, cucumbers, strawberries, and komatsuna, it shows how many plants fit with a top-view layout diagram based on plant spacing and the soil each plant needs, and you can check the weight of soil after watering and the weight per m² on a balcony (guideline 180kg/m²).
How to use Planter & Pot Soil Calculator | How Many Liters and Bags? Pot Size Chart and Plant Count (Home Gardening)
- 1In the "Soil & Bags" tab, choose the container type (pot, planter, garden bed, or enter capacity) and enter the size number or dimensions and the count
- 2If you have containers of different sizes, add them with "+ Pot (size number)" or "+ Planter"
- 3Choose whether to use drainage stones and the soil mix (commercial potting soil, 7 akadama : 3 leaf mold, and so on)
- 4See the amount of each material and how many 14L or 25L bags to buy (the bag size can be changed)
- 5In the "How Many Plants?" tab, choose a container and a crop to check the plant count and planting-position diagram
- 6If you will put them on a balcony, use the "Weight & Balcony" tab to see the weight after watering and the weight per 1m²
- 7Use "Copy result" to make a shopping note, or "Copy URL for these settings" to send it to your family
Great for
- I want to know how many liters of potting soil fit in a 65cm planter and how many 25L bags to buy
- I want a quick-reference chart of how many liters of soil size 7 and size 10 pots need
- I am making my own soil with 7 akadama : 3 leaf mold and want to know how many bags of each to buy
- I want to know how many drainage stones to use and how many grams of dolomite lime or base fertilizer to mix in
- I want to know how many mini tomatoes, strawberries, or leaf lettuce plants fit in a planter and where to plant them
- I want to estimate the soil volume and number of bags for a raised bed or garden bed
- I want to check whether lining up planters on my balcony is safe in terms of weight
Good to know
- A pot's size number is the diameter of its outer rim, and 1 go = 1 sun = about 3cm (size 5 = 15cm, size 7 = 21cm, size 10 = 30cm). The height and bottom size are set from the typical ratios of standard pots (height about 0.9 times the diameter, bottom about 0.7 times), deep pots, shallow pots, and square pots, and the volume is calculated for the tapered shape after making the inside smaller by the wall thickness.
- Soil is calculated not to the brim but to the height that leaves a water space for watering (1.5cm for size 4 and under, 2cm for sizes 5–7, 3cm for size 8 and up, and 2.5cm for planters).
- Drainage stones are 2cm thick for sizes 5–7, 3cm for size 8 and up, and 2–3cm for planters, and that volume is subtracted from the soil amount. For size 4 and under, only a drainage net is generally used, with no drainage stones.
- Planter dimensions are estimates from the inner size of commonly sold models. If a product says "capacity ○L" or "soil volume ○L", enter that number under "Enter Capacity".
- Mixing materials of different grain sizes reduces the total slightly, and the soil settles after watering. Setting "Buy extra" to 10% adds that amount before working out the number of bags.
- Plant spacing, soil per plant, and depth are general home-gardening guidelines. They vary with the variety (mini, dwarf, and so on) and training method, so also check the seed or seedling packet.
- The amounts of dolomite lime, base fertilizer, and compost are general guidelines. Follow the amount printed on the bag first. The weights are guidelines per soil type (potting soil is about 0.45kg/L dry and about 0.8kg/L after watering) and do not include the containers, plants, or water in saucers.
Questions this tool answers
Use Planter & Pot Soil Calculator | How Many Liters and Bags? Pot Size Chart and Plant Count (Home Gardening) for searches like these:
- I want to calculate the amount of soil for a planter
- I want to know the liters of soil for each pot size number
- I want to know how many bags of potting soil to buy
- I want to know how many bags of akadama and leaf mold to buy
- I want to know the amounts of drainage stones, dolomite lime, and base fertilizer
- I want to know how many vegetables I can plant in a planter
- I want to know the planting positions that respect plant spacing
- I want to check the weight and load limit of planters on a balcony
FAQ
- How many liters of soil does a 65cm planter hold?
- A standard 65cm planter (inner size about 60×20cm, depth 17cm) holds about 14L, leaving room for water space. With 2cm of drainage stones, that is about 12.4L of soil and 1.7L of stones. A deep 65cm vegetable planter (depth around 26cm) holds about 30L (about 27L of soil with 3cm of drainage stones), more than twice the standard one. Models vary, so use the labeled capacity if there is one.
- What is the guideline soil volume for each pot size number?
- For a standard pot, leaving room for water space, the amounts are about 0.2L for size 3 (9cm), 0.55L for size 4 (12cm), 1.1L for size 5 (15cm), 2.1L for size 6 (18cm), 3.5L for size 7 (21cm), 5L for size 8 (24cm), 7.5L for size 9 (27cm), and 10.7L for size 10 (30cm). Each size up adds only 3cm of diameter, but the soil volume grows about 1.4–1.5 times for sizes 8–10 and about 2 times for sizes 5–6. A deep pot holds about 1.6 times as much at the same size number, and a shallow pot a little under half (about 0.45 times).
- How many bags of potting soil should I buy?
- Add about 10% to the soil you need to allow for shrinkage after mixing and settling, then divide by the bag size and round up. For example, two standard 65cm planters (with drainage stones) need about 24.8L of soil, or about 27.3L with 10% extra, which is 2 bags of 25L or 2 bags of 14L. One deep 65cm planter (about 27L) needs about 30L with 10% extra, which is 2 bags of 25L.
- If I mix akadama and leaf mold 7:3, how many bags of each do I need?
- Split the soil you need 7:3. To make three deep 65cm planters (about 82L of soil) with 10% extra, you need about 63L of akadama (5 bags of 14L) and about 27L of leaf mold (2 bags of 14L). For a self-mixed soil, mix in dolomite lime (1–2g per 1L of soil) and slow-release compound fertilizer (2–3g per 1L of soil), and let it sit for 1 to 2 weeks before planting.
- How many mini tomatoes can I plant in a planter?
- Mini tomatoes need about 45cm between plants, 10–15L of soil per plant, and a depth of 25–30cm, so one plant per deep 65cm planter is the basic rule. A large deep 70cm planter (about 43L of soil) holds 2 plants. A standard 65cm planter (depth 17cm) is too shallow, so the roots cannot spread and it dries out easily, which makes it unsuitable for tomatoes. For pots, use size 10 or larger.
- How many strawberries or leaf lettuce plants fit in a 65cm planter?
- In a standard 65cm planter, the guideline is 2 strawberry plants (25cm spacing), 3 leaf lettuce plants (20cm spacing), and 4 pansies or violas (15cm spacing). For komatsuna or spinach, sow in 1 row (2 rows in a deep planter) with 12cm row spacing and thin to 5cm between plants once true leaves appear, which gives about 11 plants per row.
- Is the weight OK if I put planters on a balcony?
- Potting soil weighs about 0.8kg per 1L after watering, so a standard 65cm planter weighs about 11kg and a deep 65cm planter about 23kg. Compared with the residential floor load guideline (1,800N/m² in the Building Standard Law Enforcement Order, about 180kg/m²), a single deep planter alone comes to about 120kg per 1m² of its footprint. When you line up many, check the weight divided by the area they occupy, move heavy ones next to the wall, and also check your condominium's management rules.
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