Potting Soil & Fertilizer Calculator
Calculate soil volume for round, square, and tapered pots. Includes fertilizer ratios and 3D visualization aids for gardening precision.
About
Estimating the correct amount of substrate for container gardening is essential to minimize waste and ensure adequate root space. This tool computes the exact volume required for various container geometries, including cylinders, rectangular prisms, and frustums (tapered pots). Accurate volume calculation allows for the precise dosing of amendments and fertilizers, which are typically prescribed in grams per liter or cubic foot.
Different soil types possess varying bulk densities. Peat moss is light and airy, while loam or sandy mixtures are significantly heavier. This calculator adjusts for these density factors when estimating the weight of the fill, helping gardeners determine if a balcony or shelf can support the final planted weight.
Formulas
The volume V depends on the container shape. For a standard tapered flower pot (Frustum), the volume is calculated as:
Where R is the top radius, r is the bottom radius, and h is the height. For rectangular containers:
Fertilizer requirements F are derived from the manufacturers' concentration ratio C (e.g., grams per liter):
Reference Data
| Material | Density (kg/L) | Density (lbs/ft³) | Common Use |
|---|---|---|---|
| Peat Moss (Dry) | 0.1 - 0.2 | 6 - 12 | Seed starting, acidic mix |
| Potting Mix (Standard) | 0.35 - 0.45 | 22 - 28 | General container plants |
| Garden Soil (Loam) | 1.2 - 1.3 | 75 - 81 | Raised beds |
| Compost (Moist) | 0.5 - 0.7 | 31 - 44 | Organic amendment |
| Perlite | 0.03 - 0.1 | 2 - 6 | Aeration additive |
| Sand (Dry) | 1.6 | 100 | Drainage, cactus mix |
| Clay Pebbles (LECA) | 0.3 - 0.4 | 19 - 25 | Hydroponics |