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Could Growing Food in Gravel Be Pay Dirt for Sustainable Agriculture?

A new age in gardening is dawning: Geological agriculture, aka gravel gardening — a completely soil-less way to grow all kinds of crops in sedimentary rock.

Leading the charge is To Soil Less, a family business founded by former management consultant Richard Campbell in 2011.

As its website explains, “sedimentary rock is composed of the sediment of the sea or dead organic life such as fish or plants. When these rocks are impacted with water, minerals and nutrients leak out of the rock into the available moisture, which can feed root systems. Water is maintained in the system due to the condensation properties of the gravel and sand, which enables water to be stored and used over a period of time.”

The idea sprouted in 1994 when Campbell’s great uncle, Dr. Thomas Logan, discovered a watermelon growing in a gravel bed designed for weed block, where he had spit seeds the previous season.

“For 15 years, he replicated what he saw eating an abundance of crops annually,” Campbell told Sustainable Brands. “In 2008, after seeing a TV show about famine and hunger, my uncle invited me back to Nashville and [said]: ‘I have been doing this since you left and see that it works, but I can't figure out anything past that. 1) Can you figure out how and why this works? and 2) Can you take it to the people?’ I said yes to both and started looking closely, and six months later I figured it out. Since then we have been on the gravel soap box.”

After 20 years of research, Campbell recently received patent number 9,119,351 for Geological Agriculture.

How is the nutritional integrity of food maintained in this process?

“Earth's natural nutrients within sedimentary rock enable a nutrient transfer from rock, to the water, to the seed and roots,” Campbell explained. “Sedimentary rock, river rock or pea gravel releases, among other things, potassium, silica and copper when impacted with water. Each of these components provides a nutrient cocktail for plants naturally. Combined with air, sunlight, water and nitrogen fixation, you have a permanent growing ecosystem.”

Campbell asserts that gravel gardening could not only represent a viable alternative to traditional soil farming in times of resource scarcity, but across the board — and he envisions it having far-reaching implications.

“Geological agriculture will likely affect both traditional farming and distressed farming alike, but also an estimated 16 other industries will be impacted in a positive way,” he said. “Academia will study and teach the science; non-profits will use it to feed the homeless; developers will design more efficient green spaces; urban homes will have easier access to produce; astronauts will have fresh produce in space; restaurants can grow microgreens in days; K-12 students will conduct experiments in class; retailers will have gravel gardening areas within garden centers; and countries around the world will be one step closer to food security.”

When asked to clarify the differences between geological agriculture and hydroponics — a centuries-old growing method that also often grows crops in gravel — Campbell explained:

  • "Hydroponics can only be done in places with continuous electricity, water and fertilizers; gravel can be done anywhere in the world.
  • Hydroponics need continuous water flow 24 hours a day; gravel needs water once every 7 days.
  • Hydroponics need fertilizers; gravel does not.
  • Hydroponics has high start-up cost and high monthly maintenance costs; gravel costs less than $100 for most homeowners with no monthly maintenance costs and no future costs.
  • Hydroponics can only be done indoors; gravel is great outdoors and indoors.
  • Hydroponics requires highly specialized equipment; gravel uses no specialized equipment.
  • Hydroponics can never be classified as organic; gravel will likely be deemed the most organic.”

Ace Hardware is the first major retailer to embrace the technology, signing on as a pilot partner in the Washington, DC area selling To Soil Less’ Gravel Grow Cup, pre-seeded gravel grow kits for home use.

“Geological agriculture is humanity's first new science since IT,” Campbell said. “We only know 2 percent of the power embedded within sedimentary materials. Mankind has studied soil for thousands of years but not rocks. Going forward, the market to develop lines of business for gravel gardening products is now open.”

So why has it taken until now to discover this form of agriculture? Campbell outlined four major theories:

  1. Science community — Scientists generally only study what they are paid to study through research grants. Out of 100 professors engaged in America, only 2 were actually curious enough to look into it, he said.
  2. Agriculture community — Conventional agriculture is predicated on thousands of years of soil knowledge and the scientists that built them. Campbell says pure agriculturalists find the notion of gravel “insulting, fake or unreasonable.”
  3. Conspiracy — Many feel that the advent of geological agriculture means taking business away from big fertilizing companies. The truth is, Campbell points out, with over 100,000 types of vegetation and thousands of types of sedimentary rock, geological agriculture is a potentially massive untapped market opportunity for big ag players in the ongoing quest for sustainable agriculture techniques and technologies.
  4. Basic disbelief — the foundation of American psychology: The ‘don't try to sell me,’ ‘I already know everything,’ ‘why hasn't someone else done this already’ kind of mindset, Campbell says. “We talk ourselves into circles and with gravel I have seen the best of them do it.”

As of now, To Soil Less is the only player in geological ag, but Campbell encourages the industry to see past tradition and help leverage gravel’s potential on a broader scale.

“I did not create the rocks — I only added water; nature took over and out came something broader,” Campbell said. “Look to the oceans, rivers and tides to help close the food security divide.”


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