How big should the trial area be?

Large enough to be managed like the rest of the house and to give a readable harvest record — often a full row set or bay rather than a few plants.

Can I test two changes at once?

Better not. If results change, you will not know which change caused it.

Do I need statistics?

Simple replication (several trial and comparison rows) helps. For formal designs, ask an extension service or research partner.

What if a supplier runs the trial?

Agree the template, KPIs and decision rule in writing before starting, and keep your own records.

Does a good trial guarantee full-scale results?

No. It reduces uncertainty for that crop, season and site. Scale up in steps and keep measuring.

How to plan a greenhouse trial: baseline by crop and season, KPIs, sensor calibration and the scale-up decision

Reviewed: 2026-10-13 · SeedMatchGroup

Short answer

Define one change and one main KPI, record a baseline for the same crop and season, calibrate the sensors you will rely on, run the trial on a comparison area (or a matched before/after period), and decide in advance what result — over what period — would justify scaling up.

Hand calibrating a wireless climate sensor in a pepper greenhouse trial block, with row tags and a handheld EC meter — A fair trial starts with calibrated sensors and clearly tagged trial and comparison rows.

Many upgrades are judged by impression. A simple trial plan turns impression into evidence that you, your financiers and your suppliers can check. This guide gives a one-page trial template and the rules that keep the comparison fair.

One-page trial template

Field	What to write
Question	e.g. "Does the new irrigation strategy reduce water per kg without raising rejects?"
Change tested	Only one, described precisely
Crop / variety / season	Same for trial and comparison
Areas	Trial area and comparison area, mapped
Main KPI	One, with unit
Secondary KPIs	Two or three, e.g. rejects, labour hours
Baseline	Period and values from your records
Duration	At least one full crop phase or cycle
Decision rule	Result that justifies scale-up, and what stops it
Owner	Who records, who reviews

Building the baseline by crop and season

A baseline is only useful for the same crop, a similar variety and the same season. Pull it from your multi-cycle comparison. If seasons differ, use a side-by-side design in the same period instead of a before/after comparison.

Choosing KPIs

Main KPI linked to the question: marketable kg/m², L water per kg, kWh per kg, rejects %, hours per 1,000 kg.
Guard-rail KPIs: things that must not get worse (quality, rejects, disease incidence).
Write how each is measured and by whom.

Sensor calibration checklist

Check each temperature and humidity sensor against a reference instrument before the trial and at the midpoint.
Use shielded, aspirated housings at crop height where possible.
Calibrate EC and pH meters with fresh standard solutions on a fixed schedule.
Check water meters against a timed bucket test.
Log calibration dates; data from an uncalibrated sensor is flagged, not used.

Hypothetical result and decision

Hypothetical numbers for method only.

KPI	Comparison area	Trial area
Water (L per kg marketable)	30	26
Rejects (%)	7	7
Marketable yield (kg/m²)	14	14

Decision rule set in advance: scale up if water per kg falls by at least 10% with no rise in rejects over a full phase. Here water fell about 13% with rejects unchanged — the rule is met for this crop, season and site. Next step: repeat on a larger block before full roll-out.

When the trial is inconclusive

Check data quality first (calibration, missing days).
Extend the trial or repeat it in the next comparable season.
Ask an agronomist or extension specialist to review the design.
Do not scale up on an unclear result; do not drop a promising change on one noisy period either.

A trial is a small investment that protects a large one. Set one question, one main KPI, a fair baseline, calibrated sensors and a decision rule written before the results arrive.

Tools and next steps

Frequently asked questions

How big should the trial area be?: Large enough to be managed like the rest of the house and to give a readable harvest record — often a full row set or bay rather than a few plants.
Can I test two changes at once?: Better not. If results change, you will not know which change caused it.
Do I need statistics?: Simple replication (several trial and comparison rows) helps. For formal designs, ask an extension service or research partner.
What if a supplier runs the trial?: Agree the template, KPIs and decision rule in writing before starting, and keep your own records.
Does a good trial guarantee full-scale results?: No. It reduces uncertainty for that crop, season and site. Scale up in steps and keep measuring.

Sources

General planning guidance. Results depend on crop, variety, climate, water, regulation and market; numerical examples are hypothetical. Confirm decisions with qualified local specialists.