The Real Environmental Impact of Grow Space: Water, Emissions, and What the Numbers Actually Say

A transparent look at our sustainability claims with the math to back them up

You've probably heard vertical farms make big environmental claims. Less water. Lower emissions. Better for the planet. But how much of that is marketing, and how much is real?

At Grow Space, we believe you deserve to see the actual numbers. In this article, we're breaking down our environmental impact across four areas: water usage, carbon emissions, agricultural runoff, and building reuse. We'll show you the research, explain our math, and be honest about what we know — and what we're still learning.

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Water Usage: 90%+ Less Than Conventional Farming

This is the claim with the strongest research behind it. Hydroponic systems like ours use dramatically less water than traditional field agriculture.

The Numbers

At the low end, that's a 10x difference. At the high end — in hot, arid climates like Arizona where much of America's lettuce is grown — it's a 26x difference.

What the Research Says

The most comprehensive study comparing hydroponic and conventional lettuce production comes from Arizona State University, published in the International Journal of Environmental Research and Public Health (1). The researchers compared lettuce production in Yuma, Arizona — one of the largest lettuce-producing regions in the United States.

Key findings:

That's a 12.5x reduction in water usage per kilogram of lettuce produced.

Additional research confirms these findings:

• World Economic Forum (2023): "Vertical farms can use up to 98% less water than traditional agriculture." (2)
• Elsevier (2023): "Vertical farms have demonstrated reductions in water use by 28–95% compared to greenhouses." (3)
• PMC Hydroponics Review (2023): "Hydroponic farming techniques have been found to reduce water usage by up to 90% compared to conventional soil-based farming." (4)

Why the Difference?

In traditional outdoor farming, water is lost to:

• Evaporation from open fields, especially in hot climates
• Runoff that doesn't absorb into soil
• Deep soil absorption past the root zone
• Inefficient irrigation systems

In our hydroponic systems, water recirculates through a closed loop. Roots take what they need, and the rest goes back to the reservoir. Very little is lost because the system is enclosed and climate-controlled.

For a deeper dive on water usage, read our full breakdown: The Real Numbers Behind Hydroponic Water Usage

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Carbon Emissions: More Than 50% Less (And Here's the Math)

This one is more complicated — and we want to be transparent about that.

Vertical farming's carbon footprint depends heavily on one factor: where the energy comes from. About 85% of a vertical farm's emissions come from electricity usage (5). That means a vertical farm powered by coal looks very different from one powered by renewables.

The Research Context

Studies show a wide range of emissions for vertical farms depending on energy source:

• Global warming burdens vary from 0.48 to 17.8 kg CO₂e per kg of lettuce grown in hydroponic controlled environments (6)
• At the worst end (dirty grid, inefficient operation), vertical farms can produce up to 16.7 times more emissions than conventional farms (5)
• At the best end (clean grid, efficient operation), vertical farms can produce significantly less than conventional farms

This is where our location — and our energy choices — matter.

What Conventional Farming Emits (That People Forget About)

When comparing emissions, it's important to remember what conventional agriculture produces beyond just growing the crop:

• Tilling the soil — Tractors repeatedly churning fields release stored carbon from the soil and burn diesel fuel. Tilling is one of agriculture's most significant emission sources, disrupting soil structure and releasing CO₂ that was sequestered underground (7).
• Running irrigation equipment — Pumping water across large fields requires substantial energy
• Operating farm machinery — Harvesters, sprayers, and transport vehicles all burn fossil fuels
• Long-distance transportation — Most lettuce travels 1,500+ miles from California/Arizona to the Midwest in refrigerated trucks

We don't till. We don't run tractors. Our lettuce travels less than 30 miles to reach you.

Our Energy Situation

Grow Space is located in Kenosha, Wisconsin, served by WE Energies. We participate in their Energy for Tomorrow Program, which allows us to subsidize 100% of our electricity usage with renewable energy credits. This means all of our energy consumption is offset by investments in clean energy on the grid.

To be clear about what this means: Wisconsin's grid, while cleaner than the national average, would still put our emissions at approximately 5 kg CO₂ per kg of lettuce without this program — comparable to some conventional farming operations. The Energy for Tomorrow Program is what brings our electricity-related emissions to near-zero.

Watch our full video breakdown of these calculations: The Climate Impact of Grow Space - Video Sources

Our Emissions Estimate (The Math)

Here's how we estimated our direct emissions:

Energy Usage:

• We track our monthly electricity consumption
• Using the EPA's eGRID data, the U.S. average electricity carbon intensity is approximately 0.52 kg CO₂e per kWh (8)
• With our WE Energies clean energy subsidies, this drops to near-zero

CO₂ Supplementation: Plants grow faster with elevated CO₂ levels, so we supplement CO₂ in our growing room. Here's our estimate of annual CO₂ usage:

• Room volume: 1,500 ft² × 9 ft = 13,500 ft³ = 382 m³
• CO₂ boost: 1,300 ppm – 420 ppm ≈ 880 ppm above ambient
• CO₂ mass per air exchange: approximately 0.605 kg
• Estimated annual usage: 2–3 tons of CO₂ depending on air exchange rate

What the Studies Say: Research suggests that well-run vertical farms on relatively clean grids produce around 0.48 kg CO₂e per kg of lettuce when accounting for all factors (6). With our limited resources, it's difficult for us to measure our exact emissions with laboratory precision. What we can say confidently is that we're operating at the lower end of the vertical farming spectrum due to our clean energy subsidies.

Our Conservative Claim

We say we produce more than 50% less emissions than conventional farms. This is a conservative estimate we're very confident is accurate.

The real number may be significantly higher — potentially 70-80% less — but we don't want to make claims we can't fully verify. What we know for certain:

• We've eliminated tractor and tilling emissions entirely
• We've eliminated long-distance transportation emissions
• We've subsidized 100% of our electricity with renewable energy
• Our direct CO₂ supplementation is 2-3 tons annually

Until we can conduct more rigorous lifecycle analysis, we're sticking with the conservative 50%+ claim. We'd rather under-promise and over-deliver.

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Dramatically Reduced Agricultural Runoff

This benefit doesn't get talked about enough.

The Problem with Conventional Agriculture

According to the EPA, agricultural runoff is the leading cause of water quality problems in rivers and streams in the United States (9).

Every year in the U.S., according to the EPA and USGS (9, 10):

• ~500,000 tons of pesticides are applied to crops
• 12 million tons of nitrogen fertilizer are applied
• 4 million tons of phosphorus fertilizer are applied

A significant portion of these chemicals doesn't stay in the fields. Rain and irrigation wash them into streams, rivers, lakes, and groundwater.

The consequences are severe:

• Dead zones where oxygen levels are too low for marine life to survive — the Gulf of Mexico dead zone spans over 6,000 square miles (11)
• Algae blooms that contaminate drinking water
• Groundwater contamination with nitrates, which pose health risks especially for infants (11)
• Fish kills from ammonia toxicity
• Ecosystem disruption affecting biodiversity across watersheds

The Wisconsin DNR notes that "excess nutrients from manure or other agricultural runoff raise the amount of nitrogen or phosphorus in the water," leading to algae blooms, lower oxygen levels, and harm to aquatic life (12).

How We Dramatically Reduce This Problem

At Grow Space, our nutrients stay in a closed-loop system during the growing process. Here's how it works:

1. We mix precise nutrient solutions for our plants
2. The solution circulates through our hydroponic systems
3. Plants absorb what they need
4. Excess solution returns to the reservoir

When we do need to change out our nutrient water, it goes down the drain to our municipal water treatment facility — the same place your sink and shower water goes. The Kenosha Water Utility treats this water before it ever reaches local waterways. It's not running off untreated into streams, rivers, or groundwater like agricultural runoff from open fields.

The key difference: In conventional farming, fertilizers wash directly from fields into waterways during every rainstorm — completely untreated. Our nutrients never touch the ground, never run off during storms, and any water we discharge is processed by professional water treatment before reaching the environment.

Zero contribution to dead zones. Zero untreated runoff into local streams.

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Giving an Old Furniture Store New Purpose

Vertical farming doesn't require new construction on farmland. It can happen in existing buildings that would otherwise sit empty.

The Adaptive Reuse Advantage

Research highlights the environmental benefits of repurposing existing structures for vertical farming:

• "Adaptive reuse minimizes the environmental impact associated with constructing new agricultural infrastructure while revitalizing urban spaces." (13)
• "Abandoned warehouses, industrial facilities, or obsolete urban structures can be transformed into thriving vertical farms." (13)
• "The proximity of vertical farms to consumers reduces transportation costs and carbon footprint associated with long-distance food distribution." (14)

Across the country, vertical farms are being built in converted warehouses, old factories, shipping containers, and even abandoned gas stations (15).

Our Building

Grow Space operates out of a converted furniture store on Roosevelt Road in Kenosha. Rather than developing new land for agriculture (which often means clearing forests or converting natural habitats) we're using a retail space that already exists in our community.

This approach:

• Preserves natural land that would otherwise be converted to farmland
• Reduces construction emissions compared to building new agricultural facilities
• Keeps food production local to the community it serves
• Revitalizes commercial space that might otherwise sit vacant

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The Honest Summary

We're not claiming to be perfect. Vertical farming has tradeoffs primarily energy usage. Without our clean energy subsidies, our emissions would be comparable to some conventional operations. But when you look at the full picture of what we've actually built:

We're transparent about our methods because we believe you should know exactly what you're supporting when you buy from us. The math isn't always simple, and we don't have the resources to measure everything with perfect precision. But the direction is clear: local, indoor farming dramatically reduces the environmental impact of growing fresh greens.

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Frequently Asked Questions

Does vertical farming really use less water?

Yes. Peer-reviewed research consistently shows 90%+ water savings compared to conventional field agriculture. The Arizona State University study found a 92% reduction in water usage per kilogram of lettuce (1).

Is vertical farming better for carbon emissions?

It depends entirely on the energy source. Vertical farms on dirty grids can actually have higher emissions than conventional farms. Our farm in Wisconsin would produce around 5 kg CO₂ per kg of lettuce on the standard grid. However, because we subsidize 100% of our electricity through WE Energies' Energy for Tomorrow Program, our energy-related emissions drop to near-zero, making our total footprint significantly lower than conventional farming.

What is agricultural runoff and why does it matter?

Agricultural runoff occurs when rain or irrigation washes fertilizers, pesticides, and other chemicals off farm fields into waterways. It's the leading cause of water quality problems in U.S. rivers and streams, creating dead zones, contaminating drinking water, and harming ecosystems. The EPA estimates about 500,000 tons of pesticides and 12 million tons of nitrogen are applied to U.S. crops annually, much of which ends up in our waterways (9).

Does Grow Space produce any runoff?

We don't produce untreated runoff to local waterways. Our nutrients circulate in a closed-loop system during growing. When we change out nutrient water, it goes to the municipal water treatment facility (the same system that handles residential wastewater) where it's properly treated before discharge. This is fundamentally different from farm field runoff, which washes directly into streams and rivers untreated.

Why does using an existing building matter?

New agricultural development often requires converting natural land into farmland. By converting an old furniture store, we avoided this impact entirely while revitalizing commercial space in our community.

Why don't you just say you reduce emissions by 70-80%?

Because we can't prove it with certainty. We're confident the real number is higher than 50%, but with our limited resources, we can't conduct the comprehensive lifecycle analysis needed to make a more specific claim. We'd rather be conservative and accurate than make claims we can't fully back up.

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Sources & References

1. Barbosa, G.L. et al. "Comparison of Land, Water, and Energy Requirements of Lettuce Grown Using Hydroponic vs. Conventional Agricultural Methods." International Journal of Environmental Research and Public Health, 2015.
2. World Economic Forum. "Vertical farms can use up to 98% less water than traditional agriculture." 2023.
3. Elsevier. "Improving water use efficiency in vertical farming: Effects of growing systems." 2023.
4. PMC/National Institutes of Health. "Hydroponics: Current Trends in Sustainable Crop Production." 2023.
5. Blom, T. et al. "The embodied carbon emissions of lettuce production in vertical farms." Journal of Cleaner Production, 2022.
6. ScienceDirect. "Comparative environmental footprints of lettuce supplied by open-field and vertical farming systems." 2022.
7. Kraken Sense. "Agricultural Runoff: Causes, Effects, and Solutions for Cleaner Water." 2024.
8. U.S. Environmental Protection Agency. "eGRID Summary Tables." 2021.
9. U.S. Environmental Protection Agency. "Nonpoint Source: Agriculture."
10. U.S. Geological Survey. "Agricultural Contaminants."
11. Kraken Sense. "Agricultural Runoff: Causes, Effects, and Solutions for Cleaner Water." 2024.
    
12. Wisconsin Department of Natural Resources. "Environmental impacts of agricultural runoff."
13. Szopińska et al. / Cooke. "Adaptive reuse of existing structures for vertical farming." 2021-2022.
14. Green.org. "Transforming Abandoned Buildings into Vertical Farms." 2024.
15. Thomson Reuters Foundation / Context. "In the US, urban farmers use empty buildings for growing crops." 2025.