Pieter Hoff from Groasis in Steenbergen

Planting a tree of hope with Pieter Hoff van Groasis in Steenbergen. “We successfully grow trees in environments where nobody has succeeded before.”

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Brenna question

Out of the boxx

Plant trees, rather than cutting them down. That brings prosperity to poor, dry countries, reduces CO₂ emissions and solves the water problem at the same time. About ‘intelligent’ buckets, capillary water transport systems and the added value of a National Icon. Planting a tree of hope with Pieter Hoff from Groasis in Steenbergen. “We successfully grow trees in environments where nobody has succeeded before.” 

Pieter Hoff, who now lives in Steenbergen near Oss in North Brabant, was happy and excited. After two years of intensive testing in the Netherlands, his handmade ‘intelligent buckets’ had proved that they worked. The idea was to grow trees in sweltering hot, water-starved countries with 90% less water. He was convinced that all he had to do now was fine-tune his design to suit a bone-dry climate. Because that was his ultimate goal. So in 2005 he took 25 of his smart buckets to the Sahara. For a project in collaboration with the University of Oujda, the city nearest to the Sahara desert. After four years of trial and error, they succeeded: “We saw that 88% of the trees continued to grow in the desert soil, despite the heat. They were able to thrive on a total of 100 litres of water per year. Much less than with drip irrigation, which permanently requires 15 litres of water per tree per day. That was when we decided to invest in the plastic moulds that we needed to produce the growing boxes for the trees. We were ready to progress to the next stage.”

Photo: Melchert Meijer zu Schlochtern

Thousands of small islands

He comes from Hem. A ribbon-shaped village between Hoorn and Enkhuizen that used to be surrounded by thousands of islands with countless small fields that could only be reached by barge. Farms were located on transverse canals that branched off the main waterways. Early vegetables were grown in some fields. Other fields were devoted to bulb cultivation and seed potatoes. A beautiful area that has now almost completely disappeared. After WW II, the choice was either agriculture or tourism. Not a difficult decision. In the West Frisian polders, life was all about work, work and more work. 80 hours a week. So tourism seemed like a pipe-dream; this was not the place for a Venice of the North. Local administrators, often farmers themselves, decided in favour of immediate prosperity by focusing on farming, land consolidation and mechanisation.

Chitchat about cows and calves

Hoff beams as he reminisces about his childhood. When he was just two years old, he was already pulling his weight out in the fields, handing out crates as the farm workers harvested potatoes. “As soon as you could walk, your father would say: ‘come out and play’, but he actually meant come and help. Every farmer's child will tell you the same. We went to school with our rubber boots on.” His classmates got up at five o'clock; they had to go milk the cows. Or cut tulips, dig up red beets, top gladioli: “You talked about what was going on in the fields in the school playground. That you were topping your tulips or harvesting them. Others literally chatted about cows and calves. And nobody had a television.” He remembers the scene as clearly as if it happened yesterday. Accompanying his father to the ‘Melkvee Vakdagen’ in Liempde, the most important event for dairy and cattle farmers in our country. Admiring the latest tractors. “The revolution that took place in agriculture in the United States during the 1920s, was mirrored in the Netherlands in the 1950s and 1960s when everybody mechanised. The farmers had the task of feeding the Netherlands as the nation rebuilt itself after the war. I was privileged to play my part.”

Flowers, beets and potatoes

After a couple of years at a general secondary school, he attended the State Horticultural College in Hoorn, and went on to take a course in plant breeding in Wageningen. In 1970, he and his two brothers took over his father’s mixed farming business. “My educational background has given me a wide-ranging practical understanding of agriculture, horticulture and livestock farming. At home, we had 14 hectares of seed potatoes, 20 hectares of tulips and 15 hectares of lilies.” The three brothers soon decided to specialize in lilies for the cut flower market. Hoff Quality First expanded rapidly to become the second largest lily grower in our country, surpassed only by Vletter & Den Haan in Rijnsburg. “They were the Johan Cruijff of the sector and we were Ruud Krol by comparison.” Thanks to Jan de Graaff from Gresham, Oregon. A member of a well-known family of bulb growers in Lisse who emigrated to the United States. The man was a genius, Hoff says. “After years of trials and error, he managed to grow a wild lily that could withstand the rigours of being packaged and immediately opened up a new market.” That resilient plant became a craze. One stem, lots of volume. “Ideal for filling bouquets. A real money-maker.”


Hoff Quality First eventually outgrew Hem. In addition, Hoff wanted to move somewhere with sandy soil, because lilies are an autumnal root crop. Clay is not a suitable soil for automatic harvesting in the autumn. So Hoff looked at possible sites in the Noordoostpolder, Breezand, Lelystad and Steenbergen. A walk-through the streets of nearby Bergen op Zoom sealed the deal for him. “We immediately felt at home, you know, simply because the town resembled Hoorn.” In 1987, the company moved some of its operations to the new location. But 14,000 m2 of greenhouse capacity remained in Hem. For breeding and virus-free propagation of lilies. Because demand for this flower continued to rocket. They constantly developed new colours and new properties, suitable for all countries and climates. But the more Hoff travelled, the more he was confronted by the growing water shortage. And that caused him more and more concern. “Agriculture and horticulture together account for 73% of the total quantity of water used worldwide. In Africa, that figure is a horrifying 85%. And I realised that I was partly responsible.”

Declining groundwater level

At the end of the 1990s, he seemed to be the only person who was concerned about the declining groundwater level. In some countries, the rate of decline was as high as one metre per year. In spite of that, this issue was on none of the political agendas. Except in the province of North Brabant. This is deserving of a huge compliment in his opinion. Hoff: “North Brabant was one of the first areas in the world to decide to number all its water sources. Livestock breeders, horticulturists and arable farmers were required by law to report how much water they used. Scarcity of water as a policy, you have to applaud them. Especially when you compare this approach to the wastefulness that is common in other - much drier - countries.”


Hoff decided to sell up completely in 2003. He was 50 years old and ready for a new challenge after all those years of hard work. “I decided to tackle the groundwater problem. How can we ensure that plants can survive in dry areas with less water and without having to use drip irrigation? Groasis is the name he chose for his new company. He was not only motivated by idealism. “I feel a strong connection with farmers. It is disappointing that many cannot use their land well in developing countries. A comparison: “Farmers in developing countries produce an average of 10 tons of maize per hectare on very fertile volcanic soil, with 365 days of sunshine. A Dutch farmer grows 80 tons of maize per hectare, with only five months of sunshine, and without that fertile volcanic soil. That is the difference between cultivating a crop and just putting something in the ground.”

Mother Nature

Hoff quickly came up with the basic idea for his solution. "A tree has wet leaves in the morning, grass is also wet in the morning. Why should you water plants with drip irrigation? Nature achieves the same through condensation. And, as we know, rain also falls from the sky.” That was where the solution lay: using water from the air in order to cultivate trees. Nature itself was the solution. That was also true of something else, he discovered. “When we want to plant a tree, we dig a hole and put seeds in the ground. Mother Nature does not dig a hole when she wants something to grow in the earth. Everything starts with a seed that finds its way onto the ground, in animal droppings, or because it is blown there by the wind.”

Capillary water system

That seed develops into a taproot that grows perpendicularly downwards in its search for water. The soil itself remains intact. And for good reason. The soil contains a capillary water transport system that consists of a maze of tiny channels that extend down into the groundwater and through which water can rise against the force of gravity. “We destroy that capillary system, Nature does not. That explains why you find 50-metre high trees growing on rocks in the Sierra Nevada. While just 40 kilometres to the west, vines in the Napa Valley need hundreds of litres of irrigation water to survive.”


After his successful first test in the Sahara, he would go on to perform many more tests and trials with his intelligent bucket. The tally for 2016 alone was 52 experiments in 33 countries. Development and patents: both require substantial investment. Things also went wrong an 'infinite number of times’. The trees often established themselves well, but died as soon as he removed the ‘growth buckets’. It was only when he understood how Mother Nature went about things in dry and hot areas that the survival rate increased to more than 90%. And that led him to the final Eureka-moment when he discovered how you can cultivate plants much more effectively with much less water. Not with a bucket made from steel or plastic, but with one made from recycled paper with a special coating: the 'Growboxx® plant cocoon'.

Lotus leaf

The ‘growth bucket’ produced by his company Groasis looks like an overgrown lemon squeezer. With a hole in the middle for the tree. It is a smart box that extracts water from the air without outside help. The handy lid, which looks like a lotus leaf, encourages condensation and collects rain. Morning dew and rainwater then disappear under the lid. You could call the Growboxx® a water battery that automatically gives the tree a 50 cc sip of water every day. Just enough to keep the tree alive and force it to put down deep roots in search of more moisture and food instead of waiting lazily for the next automatic sip. “After a year, the root is three metres long and the tree can survive on its own. The Growboxx® slowly degrades and is used by the plant as a nutrient.”


Trees even appear to thrive and grow in hottest areas in the world with the help of the Growboxx®. In Mexico, for example, close to the United States border. Last year, the temperature reached +48°C there. There are violent sandstorms, the area is plagued by hares and the sand dunes also move. “You plant your container under the soil and when you return the next day, you find it protruding above the surface.” But believe it or not, after a few months, the score was still nearly perfect: 94.8% of the trees were still alive. “The best they have achieved with drip irrigation is 30%, in spite of 10 litres of water per plant per day. People are still cautious. They see the results but are waiting to see whether the trees will still be as healthy in two or three years’ time.”

A helping of vegetables

That is the next challenge. Drought and poverty are each other’s best friends. Farmers in poor countries often do not have enough money to buy the Growboxx. Although he knocked on many doors, he found out that the FAO, the World Bank, the African Development Bank and all the many other banks and organisations simply do not invest in people without collateral. So he modified the concept and design of the Growboxx® again. By adding four extra holes for growing vegetables. “We combine planting a tree with growing vegetables. It takes five years before you can literally pluck fruit from a fruit tree. In the meantime, the owners can earn money after just three months from the vegetables they grow. Cucumber, tomatoes, eggplants, pumpkins, melons, lettuce - and of course they can eat the vegetables themselves.” Poor rural families can recover the cost of the Growboxx® after just one year of growing vegetables. “Adding vegetables as an extra is a technical solution for a practical problem.”

Better than Apple and Porsche

The Growboxx® has won all kinds of international prizes. Including an award in Popular Science magazine in 2010, proving that it is even smarter than Apple's iPad and the hybrid Porsche 918 Spyder. The box is seen worldwide as a miracle cure for bringing infertile soil back to life. In 2016, the Growboxx® was officially awarded the status of a National Icon. This is a prize for pioneering Dutch innovations. Again good for a wave of publicity, suddenly opening doors abroad and bringing in orders from 43 countries. But, says Hoff, the big bang, that all-important push, has yet to happen: "Without that breakthrough you can’t call it a success, more of a hobby.” But he adds: “Quite a serious hobby, though.”

CO₂ debate

That much-coveted breakthrough depends on three developments, says Hoff. One: finding the right balance between cost and the benefits for the farmer. You might think that the extra vegetable compartment has solved that problem. Two: the CO₂ debate. In 2008, Hoff published his book: ‘The Treesolution. CO₂ is a gift from heaven’. This is an unexpected discordant note, because CO₂ is mainly seen as a poison even though it is actually the gas of life. A tree uses CO₂ to get its daily C. It needs that mouthful of C to grow. This process leaves O₂; oxygen that we need as humans and a waste product from trees. So trees extract CO₂ from the air, purify the air. The problem is not CO₂, but the excessive concentration of CO₂ emitted by factories and cars. “Why not make a virtue of necessity”, says Hoff, just look at the problem from a different perspective: “Hey, we can earn money from CO₂. By planting instead of felling trees.” So far we have deforested two billion hectares of land, an area as large as Canada, and there are no signs that this will stop. As a result, the CO₂ concentration in the atmosphere continues to increase. Because there are fewer and fewer trees to absorb it and break it down. The conclusion: “We can solve the climate problem by reforesting the world.”


The Treesolution is a handy idea for making the Netherlands CO₂-neutral within ten years. For a fraction of the money that others are reserving for this goal. Finance Minister Wiebes believes that this will bring our prosperity to a halt, but that is nonsense. Planting trees will actually stimulate prosperity. Strangely enough, nature organisations do not want to support the plan. “They say that you shouldn’t use trees to reduce CO₂. In most cases, they fear that this strategy will be seen as an Apostolic Pardon. So that man can continue as before without mending his ways.” Every single NGO organisation that exists seems to have adopted an attitude of self-interest in the face of a problem that affects the whole world.  “On the one hand, we say that we will tackle the problem by reducing our fossil fuel consumption to zero by 2050. And as an interim measure, reduce the net emissions of CO₂ to zero by 2030. This is only possible if we plant enough trees.” In his opinion this is the true challenge: convincing people that they can earn more from planting trees rather than felling them. “Obviously I do not believe that we will reverse climate change just by planting trees. But this can be part of our climate solution and also help fight poverty at the same time.”

Food revolution

And finally point three, something that scientists have known for a long time. According to the UN, no fewer than 48 countries will suffer a chronic water shortage by 2025. One very expensive solution is to convert seawater to fresh water. But that has a far-reaching effect on the oceans, says Hoff. They will become saltier and green, and algae will form. Just consider that water shortage in the context of a growing world population of more than ten million: there will be less and less water and more and more consumers. “The water problem will soon become a political problem. Every government knows that food must be kept affordable. If not, you end up with a revolution. That is why there is a taboo on taxing water, because that means that you will no longer be able to make many products.”


An example: “A vine consumes 4000 litres per year. That is fifteen litres every day, 250 days a year. There are 2500 vines on each hectare. Suppose a wine producer has to pay one cent per litre. That is 40 euros per vine. A vine from which you can make two or three bottles of wine at the most.” Hoff knows from experience that governments find it difficult to curb water use. That is why they are waiting for technical solutions to make agriculture and animal husbandry more water-efficient. You often only see legal measures when there is a realistic alternative. “Twenty years ago, hydroponics was developed in our country for tomato cultivation. This involves growing plants in water. Since then, methyl bromide gas may no longer be used to sterilise the soil. The government had known that this was a bad practice for some time before. But there was no alternative”, says Hoff. “Hydroponic cultivation was the solution for this problem back then, just as the Growboxx® will solve today's problem of water wastage in agriculture , meaning that governments will be able to ban drip irrigation, which is not at all efficient as the vine example proves.”

Not a mastless ship

It all started with an idea, a very simple idea in fact. If he had known that it would take fifteen years to come up with a concrete product, he might have thought twice about the whole adventure. But he is not alone. At Groasis, he is assisted by volunteers and experts who help him to unravel mysteries that lie outside his area of expertise. “Think of me as the spiritual beginning, the person who never gives up. Even so, nothing would have come of it without all those other inspired and talented people.” His son is also passionate about the business. He lives in London and his twelve years of experience in the corporate world will be very useful when the company reaches its critical mass. “Groasis is not a mastless ship. The company is growing fast. As long as we remain curious and critical. And do not stop before the product is adopted on a large scale. Everybody who strives to achieve something goes through a dip. You should not be discouraged by setbacks and mistakes. Regardless of whether you are an athlete, a student or an entrepreneur. He muses: “It is also immensely satisfying. We grow healthy trees in areas where everybody has failed in the past.”



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