Plant spacing calculator
A 100 sq ft bed planted 1 ft apart on a square grid holds 100 plants, each in its own cell. Enter the usable area and the on-center spacing to get a whole-plant count, the planting density and any space left over. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Area
- 100
- Spacing
- 1
- Cell area
- 1
- Plants
- 100
- Density
- 1
- Used area
- 100
A plant spacing calculator turns a planting bed area and an on-center spacing into the integer plant count you need before you order seedlings, plugs, or seed packets.
How plant count is derived from bed area and on-center spacing
A rectangular planting bed is modeled by its usable surface area only; paths, trellises, and unplanted borders should already be subtracted from the number you send. On a square planting grid the same on-center spacing applies along both axes, so each plant claims a square cell whose side is the spacing and whose area is spacing squared. Density equals one over cell area and answers “how many plants per unit of bed area at this spacing,” which is handy when you scale the same spacing across several beds.
Used area equals plant count times cell area, and unused area is the remainder that is too small for another full cell—useful when you decide whether to tighten spacing slightly or leave a walkway strip. Area and spacing must use consistent units: square feet with feet, square metres with metres, square inches with inches. The calculator never converts units; it only needs the dimensionless ratio of area to spacing squared.
Spacing must be strictly positive because zero spacing would imply infinitely many plants and negative spacing has no meaning on a grid. Area must also be positive; a zero-area bed is not a planting surface. When the bed is smaller than one cell the plant count is zero rather than an error, which matches the geometry of a full on-center cell that does not fit.
The response does not consult crop-specific minimum spacing charts, triangular packing offsets, or staggered rows—those are design choices you apply by changing the spacing you enter or by using a different layout model.
Practical tips, limits, and related searches
Measure the clear planting area inside bed walls after subtracting permanent paths or large obstacles, then choose a spacing that matches seed-packet guidance, nursery tags, or your own trial results—six inches, thirty centimetres, and one foot are common targets, but the tool accepts any positive pair of area and spacing in consistent units. If unused area is large, either reduce spacing slightly so more whole cells fit, enlarge the bed, or accept the remainder as a service strip; this calculator never adds a partial plant.
Keep dimensions inside the published absolute range so counts cannot overflow into non-finite results the solver must reject. Prefer this capability when you already know usable area and target square-grid spacing and only need an integer plant count and density; if your source is length and width, multiply them first (after converting to the same unit) and pass the product as area.
What you can do with it
Raised-bed seedling order
Gardeners enter bed area and packet-recommended on-center spacing to learn how many plants or plugs to buy before a weekend planting day.
FAQ
How many plants fit in a bed?
On a square on-center grid, plants = floor(area / spacing²). Example: area 100 and spacing 1 → 100 plants; area 50 and spacing 2 → floor(50/4) = 12 plants.
What does on-center spacing mean?
It is the distance from the centre of one plant to the centre of the next, equal along rows and columns for the square grid this tool models. Cell area is spacing squared.
What if spacing is zero or negative?
Plant on-center spacing must be strictly positive; zero or negative spacing cannot define a planting cell.
Does this use triangular or hexagonal packing?
No. It models a square grid only. For denser staggered layouts, adjust spacing yourself or use a specialized packing model; do not expect this calculator to offset rows.
Is the plant spacing calculator free?
The browser tool is free and runs locally.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/home/plant-spacing \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"area":100,"spacing":1}'const res = await fetch("https://api.kit.forhosting.com/home/plant-spacing", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"area": 100,
"spacing": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/home/plant-spacing",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"area": 100,
"spacing": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/home/plant-spacing", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"area":100,"spacing":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"area":100,"spacing":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/home/plant-spacing", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"area": 100,
"spacing": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "home.plant_spacing",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Zero or negative spacing is rejected with a clear invalid_input error instead of inventing infinite plants, and non-positive bed area is rejected the same way.
How plant count is derived from bed area and on-center spacing
The maximum number of whole cells that fit is the floor of bed area divided by that cell area: plants equals floor of area over spacing squared. On success the tool echoes rounded area and spacing, publishes cell_area, plants, density, used_area, unused_area, formula, message, and steps so you can audit the arithmetic by hand or in automated tests.
How to call the API and what comes back
String forms of numbers are accepted when they match a strict finite numeric pattern; unit suffixes, thousand separators, or free text fail validation. Prefer sending numbers rather than pre-formatted strings when you control the client; when you must send strings, avoid unit labels that would fail the finite-number pattern. Round-trip checks are easy: recompute spacing squared, divide area by that cell area, take floor, and confirm the published plant count and unused remainder match. Send a JSON body with two required fields: area (aliases bed_area, bed, surface, surface_area, sq_area, A) and spacing (aliases plant_spacing, space, gap, S, interval, on_center, centres, centers). Both must be finite positive numbers within the published absolute range so the squared spacing and the ratio remain finite in IEEE double precision on the Worker and in the browser. On success the response sets cell_area to spacing squared, plants to the non-negative integer floor of area over cell_area, density to one over cell_area, used_area to plants times cell_area, unused_area to area minus used_area, formula to the published expressions, message to a short English summary, and steps to an ordered substitution log. Failed validation—missing fields, non-finite numbers, zero or negative spacing, non-positive area, or values outside absolute limits—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item.
Practical tips, limits, and related searches
When teaching or writing tests, pair an exact multiple (area one hundred, spacing one → one hundred plants) with a non-exact case that leaves unused area, and include a deliberate zero or negative spacing to prove the invalid_input path. This landing targets people searching for a plant spacing calculator, how many plants per bed, garden on-center spacing, planting grid plant count, or plants from bed area online; it is not a soil volume or mulch bag estimator, not a crop calendar, not a companion-planting advisor, and not a triangular or hexagonal packing solver. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when you deliberately send zero spacing to verify error handling. Homeowners, school garden coordinators, and SaaS landscape tools can all call the same endpoint for reproducible take-offs without sharing a spreadsheet formula that drifts between browsers.
Integration use cases
Market-garden block take-off
Growers feed block area and crop spacing into the API and attach plant count, density, and steps to a transparent production plan.
Golden fixtures for garden apps
Developers generate known-good exact and remainder cases plus deliberate zero-spacing rejections for unit tests and CI.