Spanish outdoor cultivation versus vertical farming: what a CO₂ comparison actually shows
Source: VFD.com
An initial reaction might be: "That makes sense, because you save more than 2,000 km of truck transport." Yet the situation is not that straightforward. Assuming an average diesel consumption of 40 liters per 100 km for a 15-ton refrigerated truck transporting lettuce from Murcia to Amsterdam over a distance of 2,100 km, and a CO₂-eq emission factor of 3.468 per liter of fuel, based on Dutch emission factor data, transport emissions amount to 0.20 kilo CO₂-eq per kilo of lettuce.
The study assumes electricity consumption of 15 kWh per kilo of product for lighting, climate control, and irrigation, with cultivation taking place at or near the point of consumption and therefore involving no transport emissions. Full-ground greenhouse cultivation results in 1.21 kilo, hydroponic greenhouse cultivation in 1.45 kilo, and vertical farming, again assuming 15 kWh per kilo of product and grid electricity, in 8.18 kilo CO₂-eq per kilo of lettuce.
Under this scenario, greenhouse cultivation in soil results in emissions of approximately 0.60 kg CO₂-eq per kilo of lettuce, hydroponic greenhouse cultivation in around 0.75 kg, and vertical farming in roughly 2.40 kg. In the Netherlands, natural gas and coal together still accounted for 60% of electricity generation in 2022, the year referenced in the studies mentioned above, but this had fallen to 48% by 2024 in favor of wind and solar energy, according to figures from the Central Bureau of Statistics.
Why this matters: For operators, this is a water-management story. The useful signal is that direct substrate measurements can help cut drain loss materially without giving up yield or fruit quality, which is exactly the kind of controllable efficiency gain a facility can build on.
Frequently Asked Questions
Why does substrate sensing matter in free-drain strawberry systems?
Because drain percentage tells a grower what already happened, while substrate moisture and EC data show root-zone conditions directly. That makes it easier to cut water loss without guessing.
What is the operator takeaway from this trial?
If the thresholds are understood well enough, growers can reduce drain water materially while protecting yield and fruit quality, which makes sensing an operational tool instead of a reporting tool.
