Three growing modes and what each costs
A grower is choosing how much of the environment to buy. Indoors, everything is supplied and paid for. Outdoors, everything is free and nothing is controlled. A glasshouse sits between the two and costs accordingly.
That single decision determines the cycle length, the energy consumption, the failure modes, the number of harvests per year and the price of the result. It reaches a buyer through all of them.
This page covers what each mode controls and what it does not, where each fails, what the energy arithmetic actually looks like, and what a buyer can and cannot infer from a product described as one or the other.
⚠️ Scope. This page describes a process and what can be verified from documents. It does not describe what a product does to a person, gives no amounts, and does not replace a healthcare professional.
🔴 What indoor growing buys
Light
Entirely supplied. Intensity, spectrum and schedule are all set by the grower, and the crop is independent of the season.
Temperature and humidity
Controlled within a range, by heating, cooling and dehumidification. The grower sets the numbers and the equipment holds them.
Carbon dioxide
Sometimes supplemented above ambient, which raises the ceiling on photosynthesis when light and temperature are already generous.
The consequence
Multiple crops per year, in any climate, on a schedule the grower chooses. That is the whole proposition.
What indoor growing costs
Electricity
Lighting is the dominant load, and climate control follows it. It is the largest running cost by a wide margin.
Capital
Lamps, ventilation, dehumidification, control systems and the building itself. The outlay per unit of growing area is substantial.
Dependence
Everything runs on equipment. A power failure of any length is a crop event rather than an inconvenience.
The environmental position
Indoor production has a considerably higher energy footprint per unit than the alternatives. It is a real cost and it is rarely part of a product description.
What outdoor growing offers
Free light
Sunlight at an intensity no lamp matches, over an area no lamp covers, at no cost.
Free volume
Plants can reach a size that indoor growing cannot accommodate, in soil that provides its own buffering.
Low input cost
No lighting, no climate control, and generally no supplementary carbon dioxide. The running cost is a fraction of the alternative.
One harvest
The season allows a single crop in temperate climates. That is the fundamental constraint.
What outdoor growing cannot control
The weather
Rain during flowering, an early frost, a heatwave at the wrong moment. Any of them can take a crop that was doing well.
The humidity
Which matters most in late flowering, when dense structures hold moisture and pathogens establish inside them.
The photoperiod
Flowering starts when the season dictates. The variety must fit the latitude or it does not finish.
The pests
Everything present in the landscape has access. Management is possible; exclusion is not.
🔴 The glasshouse position
What it controls
Temperature partly, humidity partly, rain entirely, and pest access substantially. It is a filter rather than a seal.
What it adds optionally
Blackout screens to lengthen the dark period, and supplementary lighting to shorten it. Together they decouple the crop from the calendar.
What it keeps
Sunlight as the primary energy source, which is the whole economic argument for the arrangement.
What it costs
Structure, screens, motors, heating and control systems. Substantial capital, much lower running cost than indoor growing.
Cycles per year
Indoors
Several, limited only by the cycle length of the variety and the turnaround between crops.
In a glasshouse with light control
Two to four in most climates, depending on how much supplementary lighting is used through winter.
Outdoors in a temperate climate
One. The season permits nothing else.
Why this dominates the economics
Because the capital is amortised across the crops it produces. A building used four times a year and one used once are different investments entirely.
Where each mode fails
Indoors
Equipment. Power failure, climate control failure, a light leak, or a pest introduction into a closed space with no natural predators.
In a glasshouse
Extremes that exceed the structure’s capacity, and humidity in a space that is warm and enclosed.
Outdoors
Weather at the wrong moment, principally rain during late flowering. It is the largest single cause of loss.
The common failure
Pathogen development in dense flowers under humidity, which every mode faces and each addresses differently.
The claim that indoor is better
What is usually meant
That indoor material is more consistent, denser, and cleaner in appearance. As a general observation about what reaches the market, there is something in it.
What actually causes that
Control, and the fact that indoor production is expensive enough to justify careful handling downstream. The mode correlates with the care rather than causing the quality.
What a good outdoor crop looks like
Indistinguishable from indoor material on the certificate, and frequently different in appearance because sunlight produces a different growth habit.
Where the claim fails
As a rule. Poor indoor crops exist in quantity, and excellent outdoor crops exist. The mode predicts a tendency rather than an outcome.
The appearance difference
Indoor material
Typically denser and more uniform, grown under constant conditions at a fixed distance from the light source.
Outdoor material
Frequently looser in structure, larger overall, and more variable between plants. Sunlight from a moving source produces a different form.
What that means for grading
Outdoor material can be graded lower on appearance while measuring comparably. It is a presentation difference more than a composition one.
What the certificate shows
Content and contaminants, which do not track appearance in either direction.
Contaminants and where each is exposed
Indoors
A closed environment where a pest introduction spreads with no natural check. Growers frequently respond with crop protection products, which then appear on a panel.
Outdoors
Environmental exposure: drift from neighbouring agriculture, deposition from the air, and whatever the soil contains.
In a glasshouse
Both, moderated. Enclosed enough to limit drift, open enough to have a pest ecology.
What settles it for a buyer
The panel on the certificate. Every mode has plausible routes and none is inherently clean.
Water use
Indoors
Recirculating systems are common and efficient. Water consumption per unit of production is low.
In a glasshouse
Between the two, with recirculation possible and evaporation higher.
Outdoors
Rainfall where the climate provides it, irrigation where it does not. Consumption per unit is highest and the water is generally not treated as a cost.
What follows
Water and energy point in opposite directions. Indoor growing saves water and spends electricity; outdoor growing does the reverse.
The energy comparison honestly
The indoor figure
Lighting dominates, and it runs for long hours across the whole cycle. Per unit of production, the consumption is high by any agricultural standard.
The glasshouse figure
Heating and supplementary lighting, seasonally. Considerably lower than fully indoor production in most climates.
The outdoor figure
Effectively nothing beyond irrigation and machinery. It is ordinary field agriculture.
Why this rarely appears
Because no framework requires disclosure and because it does not favour the highest-priced category. It is a real difference presented nowhere.
Organic certification and the modes
What the rules require
Production in and connected to living soil, alongside the input restrictions. Both conditions must hold.
What that excludes
Soilless production, which is common indoors. Indoor growing in soil can qualify; hydroponic production cannot.
What it does not concern
Whether the light is natural. An indoor soil crop meeting the input rules is not excluded for being indoors.
The practical position
Most certified organic production of this crop is outdoor or glasshouse, because that is where soil growing is normal.
What each mode does to a variety
Under lamps
A variety expresses within a narrow, repeatable set of conditions. What it does is consistent across crops.
Under sun
The same variety experiences a different spectrum, a different intensity profile through the day, and a season of varying weather. It expresses differently.
Which is the true expression
Neither. A phenotype is a genotype under conditions, and both sets of conditions are real.
What that means for comparison
The same variety indoors and outdoors gives different material. It is not a failure of either crop.
What a buyer can verify
The certificate
Content, compliance and contaminant panels. It applies identically to all three modes.
The organic mark
Where present, it implies soil growing under the Union scheme, which narrows the possibilities.
The mode itself
Only if the seller states it, and it is not verifiable from any document. It is a claim rather than a record.
What appearance suggests
A tendency, not a fact. Dense uniform material is more likely indoor and this is not a determination.
Where the price difference comes from
The energy
The largest component of the indoor cost, and the one that scales directly with production.
The capital amortisation
Spread across more crops per year indoors, which partly offsets the higher outlay.
The yield per area
Much higher indoors per square metre of building, and much lower per unit of energy.
What reaches the buyer
A price that reflects the production cost, and a market expectation that indoor material commands a premium beyond it.
What the modes are actually optimised for
Indoors
Consistency and scheduling. A buyer ordering the same product monthly gets the same product, which is worth a great deal commercially.
Outdoors
Cost per unit. It is the only mode that produces at a price suited to extraction and bulk supply.
Glasshouse
The compromise, and increasingly the default for serious European production. Sunlight as the energy source with enough control to schedule around the weather.
Why all three persist
Because they serve different parts of the market, and no single mode is best at consistency, cost and scheduling simultaneously.
The seasonality nobody mentions
What an annual harvest means
An outdoor crop arrives once. Everything sold from it through the following year is material that has been in storage for progressively longer.
Why that matters to a buyer
Because the degradation clock started at harvest. A purchase made eleven months after an outdoor harvest is buying eleven-month-old material, whatever the packaging date says.
What indoor production changes
Material arrives continuously, so the gap between harvest and purchase stays short. That is a genuine quality advantage and it is rarely the one advertised.
The question that reaches it
The harvest date, or failing that the analysis date on the certificate. Either establishes roughly how long the material has existed.
What the analysis date tells you
Why it is a proxy
Testing happens shortly after production in any serious operation. The date on the certificate is therefore close to the date the material was made.
What a distant date indicates
Material that has been in storage. It is not a defect and it does bear on the aroma, which declines on a timescale of months.
What a recent date indicates
Recent production, which for an outdoor product means shortly after the annual harvest and for an indoor product means any time.
Why this is the most useful date available
Because no other date on any document relates to when the material actually existed. Packaging and best-before dates are set administratively.
A short glossary
Photoperiod control
Using blackout screens and supplementary lighting to set the dark period independently of the season.
Cycle
One complete crop from planting to harvest, whose length and frequency determine how the capital is amortised.
Yield per unit of energy
Production divided by the electricity consumed, which is the figure that makes indoor and glasshouse operations comparable.
Living soil requirement
The Union organic rule that crops be grown in and connected to soil, which excludes soilless production regardless of the growing mode.
Late-flower humidity
The condition in which dense maturing structures hold moisture, which is the principal pathogen risk in every mode.
The five checks that apply to any product
The batch certificate
Request it with the number printed on the packaging. A general document for the product line does not cover this batch, and those differences are exactly what it should record.
Total THC
Delta-9-THC plus THCA multiplied by 0.877, because THCA becomes THC under heat and the limit applies to the sum, not to either value alone.
Price per milligram
A division, not an opinion. The only figure that makes two products comparable, whatever the format, process and pack size.
The claims
Without an authorisation number in the EU Register these are assertions, not data — and for cannabidiol that register contains no authorised entry to this day.
The seller’s details
Company name, address and contact. Without them there is also no counterparty to turn to if something turns out to be wrong.
How this connects to the rest
With photoperiod
The mode determines whether the grower sets the dark period or the season does.
With hydroponics and soil
An independent axis. Any mode can use either medium, though the organic rules constrain the combination.
With contaminant panels
Each mode has plausible routes and the panel is what addresses all of them.
With price
The energy and the cycles per year are where most of the price difference between modes originates.
What this is for in practice
When indoor is advertised
It indicates consistency and scheduling rather than quality. Both good and poor material comes from every mode.
When outdoor is advertised
It indicates a lower cost base and a single annual harvest. It says nothing about the result.
When organic is claimed
It implies soil growing, which narrows the possibilities considerably.
When comparing
The certificate and the per-milligram price. The mode is a claim rather than a record.
Frequently asked questions
What does indoor growing actually buy? Control over light, temperature, humidity and schedule, and therefore several crops a year in any climate.
What does it cost? Electricity above all, then capital and a dependence on equipment. Its energy footprint per unit is high by agricultural standards.
Why only one outdoor harvest? Because the photoperiod is set by the season. In temperate climates it permits a single crop.
What does a glasshouse control? Rain entirely, temperature and humidity partly, pest access substantially, and with screens and lamps, the photoperiod as well.
Is indoor material better? It tends to be more consistent and denser in appearance. On the certificate, good outdoor material measures comparably.
Why does outdoor material look different? Sunlight from a moving source at high intensity produces a different growth habit: larger, looser and more variable.
Which mode is cleanest? None inherently. Each has plausible contamination routes, and the panel on the certificate is what addresses them.
Which uses less water? Indoor recirculating systems, substantially. They spend electricity instead, so the two comparisons point in opposite directions.
Can indoor production be organic? If grown in soil and meeting the input rules, yes. Soilless production is excluded regardless of the mode.
Is the mode recorded anywhere? No. It is a seller’s claim rather than a documented fact, and no certificate carries it.
What we check and what we do not
We check what can be checked from documents: official registers, declared contents, certificates of analysis, arithmetic. We test no products, rank nothing, and assert no effects.
The reason indoor material carries a premium is not that the mode makes better plants. It is that the mode makes predictable ones, on a schedule, and predictability is what a commercial buyer is generally paying for.
That is a real thing to pay for, and it is not the same as quality. A well-grown outdoor crop measures comparably on every certificate row and costs a fraction of the energy to produce — which is why the glasshouse, sitting between the two, is where most serious European production has ended up.