Gardening Calculator

Plan plant spacing, bed layout, expected harvest, and soil or mulch volume for your vegetable or flower garden. Supports metric and imperial units plus square‑foot gardening.

1. Bed size

Tip: A common raised bed is 4 ft × 8 ft (1.2 m × 2.4 m).

2. Crop & spacing

Distance between plants in the row.

Distance between rows.

Optional. Used to estimate total harvest.

Planting layout

Bed area: –

Plants per row: –

Number of rows: –

Total plants: –

Plants per sq ft: –

Estimated harvest

Yield per plant: –

Total yield: –

Actual harvest depends on variety, climate, soil, and care. Use as a planning guide.

How this gardening calculator works

This tool combines several common gardening calculators into one place: plant spacing, bed layout, yield estimation, soil and mulch volume, and square‑foot gardening capacity. It is designed for home vegetable and flower gardeners using raised beds or in‑ground rows.

Plant spacing and layout formulas

For a rectangular bed, the area is:

Area = Length × Width

To estimate how many plants fit in the bed, we treat spacing as a grid:

Plants per row = floor( Bed length / in‑row spacing )
Number of rows = floor( Bed width / between‑row spacing )
Total plants = Plants per row × Number of rows

Plants per square foot is then:

Plants per sq ft = Total plants / Bed area (in sq ft)

Yield estimation

If you enter an estimated yield per plant (for example, 1 lb per tomato plant or 0.5 lb per lettuce head), the calculator multiplies:

Total yield = Total plants × Yield per plant

These values are approximate and assume healthy plants under good growing conditions.

Soil and mulch volume

Soil volume is simply bed area times depth. The calculator converts everything to cubic feet internally:

Area (ft²) = Length × Width (in ft)
Depth (ft) = Depth (in) ÷ 12
Volume (ft³) = Area (ft²) × Depth (ft)

From cubic feet we convert to cubic yards and liters:

Volume (yd³) = Volume (ft³) ÷ 27
Volume (L) ≈ Volume (m³) × 1000

Number of bags is:

Bags needed = Volume / Bag size (rounded up)

Square‑foot gardening

In square‑foot gardening, a bed is divided into 1×1 ft squares. The number of squares is:

Squares along length = floor( Bed length in ft )
Squares along width = floor( Bed width in ft )
Total squares = Squares along length × Squares along width

Each crop has a recommended number of plants per square (for example, 1 tomato, 4 lettuce, 9 beets, 16 carrots). The calculator multiplies:

Total plants = Total squares × Plants per square

Practical tips for using the calculator

  • Leave room for paths. If you are planning multiple beds, subtract path width from your total garden area.
  • Adjust spacing for your climate. In hot, dry climates you may want slightly wider spacing to reduce competition for water.
  • Use deeper soil for root crops. Carrots, parsnips, and tomatoes benefit from 12 in (30 cm) or more of loose soil.
  • Over‑plant slightly. Germination is rarely 100%. Plant a bit more and thin seedlings if needed.

Frequently asked questions

Can I mix metric and imperial units?

Yes. You can choose feet or meters for bed dimensions and inches or centimeters for spacing and depth. The calculator converts everything internally and keeps the results consistent.

How do I choose yield per plant?

Yield per plant varies widely by variety and conditions. As rough starting points for home gardens:

  • Lettuce (head): 0.5–1 lb (0.2–0.45 kg) per plant
  • Tomatoes (staked): 8–15 lb (3.5–7 kg) per plant over the season
  • Carrots: 0.1–0.2 lb (40–80 g) per plant
  • Onions: 0.25–0.5 lb (0.1–0.25 kg) per bulb

Use conservative numbers if you are new to gardening.

Does this calculator handle succession planting?

Not directly. This tool assumes one crop in the bed at a time. For succession planting, plan each crop separately and add up the soil needs (which usually stay the same) while adjusting plant counts and yields for each planting.