Vegetable Yield Calculator
Work out how many plants fit in a vegetable bed and how many kilograms of produce that bed should return over a season, per plant and per square metre.
🌱 What is Vegetable Yield?
Vegetable yield is the weight of edible produce a planting returns, expressed either per plant or per unit of ground. It is the number that turns a garden plan into a food plan. Knowing that a bed is 3.6 square metres tells you nothing useful on its own, but knowing that the same bed should return roughly 37 kilograms of tomatoes tells you whether to plant one bed or three, how many jars to buy for preserving, and whether the crop justifies the space it will occupy for five months.
Gardeners, allotment holders and smallholders use yield estimates in several concrete ways. Someone planning a season works backwards from how much of each vegetable a household actually eats to decide how much ground each crop deserves. A market gardener selling at a weekly stall needs to know whether a bed will produce enough volume to be worth harvesting, washing and transporting. A community garden allocating plots uses yield per square metre to compare crops fairly, since a bed of carrots and a bed of zucchini occupy the same ground but return very different weights. Anyone costing a garden compares the value of the expected harvest against the cost of seed, compost, fertiliser and irrigation.
Two misconceptions cause most of the disappointment. The first is trusting seed-packet yield figures, which are usually derived from trial plots under ideal conditions with a full-length harvest window, and can be double what an open garden returns. The second is assuming that every seed sown becomes a harvested plant. Germination failure, thinning, slugs, cutworms, damping off, transplant shock and one badly timed frost routinely remove 15 to 30 percent of a direct-sown stand before the crop is anywhere near maturity. An estimate that ignores both effects can be out by a factor of two or more.
This calculator handles both. It derives plant count from your real row and in-row spacing rather than from a guess, applies a survival rate you set yourself, and multiplies through by a per-plant yield you can override with figures from your own past seasons. It then shows what the same bed would return under every other preset crop, so you can see directly whether the ground is better used for something else.
📐 Formula
📖 How to Use This Calculator
Steps
💡 Example Calculations
Example 1 — Standard Tomato Bed
3 m × 1.2 m bed, tomatoes at 75 cm rows and 45 cm in-row, 4 kg per plant, 85% survival
Example 2 — Raised Carrot Bed
2.4 m × 1.2 m raised bed, carrots at 30 cm rows and 5 cm in-row, 0.09 kg per root, 80% survival
Example 3 — Single Zucchini Row
6 m × 1 m strip, zucchini at 90 cm rows and 60 cm in-row, 3.5 kg per plant, 90% survival
❓ Frequently Asked Questions
🔗 Related Calculators
How do I calculate vegetable yield per square metre?
Divide the total expected harvest by the bed area. Total harvest is plant count multiplied by the survival rate and by the yield per plant, and plant count is bed area divided by the product of row spacing and in-row spacing in metres. A 3.6 m² tomato bed at 75 cm by 45 cm holds about 11 plants, which at 85 percent survival and 4 kg per plant gives 37.4 kg, or 10.39 kg/m².
How much does one tomato plant yield?
A healthy indeterminate tomato in an open temperate garden typically returns 3 to 5 kg over a season, and this calculator uses 4 kg as its preset. Determinate bush varieties give less, around 2 to 3 kg, but ripen in a tighter window. Glasshouse tomatoes with a long season and controlled feeding can exceed 10 kg per plant.
How many vegetable plants fit in a raised bed?
Plant count equals bed area divided by the space each plant occupies, which is row spacing times in-row spacing. A 2.4 m by 1.2 m bed is 2.88 m². At 30 cm rows and 5 cm in-row for carrots each plant occupies 0.015 m², so roughly 192 carrots fit. At 75 cm by 45 cm for tomatoes each plant needs 0.3375 m², so only about 9 fit in the same bed.
What is a realistic plant survival rate for a vegetable garden?
Direct-sown crops usually establish at 70 to 85 percent once thinning, poor germination and seedling pests are accounted for. Transplanted seedlings that were hardened off properly commonly survive at 90 to 95 percent. Setting this figure to 100 percent will make the calculator overstate your harvest, so allow for real losses.
Does closer spacing always increase total harvest?
No. Closer spacing raises plant count, so total bed yield rises at first, but competition for light, water and nutrients reduces the yield of every individual plant. Beyond a crop-specific density the curve flattens and can fall, and quality suffers first: smaller heads, thinner roots, more disease in the crowded canopy.
Should I use row spacing or square-foot spacing?
Both work, and the calculator handles either. For a traditional row layout, enter the real distance between rows and between plants within a row. For a square-foot or grid layout, enter the same value for both spacings, since a grid plants on a square lattice. A 30 cm grid means 30 cm rows and 30 cm in-row.
How do I estimate yield for a vegetable not in the list?
Select Custom, then type the spacing and per-plant yield from your seed packet or supplier catalogue. Packet spacing is generally reliable, while packet yield figures tend to be optimistic, so it is worth reducing a quoted yield by 20 to 30 percent for a first-season estimate.
Why does the calculator round the plant count?
You cannot plant a fraction of a vegetable. The bed area divided by the space per plant usually lands on a fractional number, so the result is rounded to the nearest whole plant before harvest is calculated. This is why the harvest chart rises in small steps rather than as a perfectly smooth curve.
How much of a family's vegetables can one bed supply?
As a rough guide, an adult eating vegetables daily consumes around 100 to 150 kg per year across all types. A 3.6 m² tomato bed producing 37 kg covers the tomato share comfortably but is a small fraction of the total, which is why a self-sufficient kitchen garden is usually quoted at 50 to 100 m² per person.
Does this calculator account for succession planting?
No, it estimates a single planting. For fast crops such as lettuce, radish, spinach and bush beans you can multiply the result by the number of successive sowings your season allows, typically two or three in a temperate climate and more in a long growing season.
What units does this calculator use?
Bed length and width are in metres, both spacings are in centimetres, and yield per plant is in kilograms. Results are reported as total kilograms for the bed, kilograms per square metre, plant count and bed area in square metres.
Is yield per plant the same as marketable yield?
Not quite. The preset figures represent total harvested weight including produce that is small, split, blemished or over-ripe. Commercial marketable yield is typically 10 to 25 percent lower because graded-out produce is discarded. For home use most of that produce is still perfectly edible.