Growing

What's better? Growing in Soil or Hydroponically?

It’s a question a lot of people like to see answered. After all, you want to eat what’s good for you and not what people try to sell you! While there is a lot of research out there comparing various systems, plants and growing conditions, studies have found that veggies grown hydroponically do just as well as soil-based grown veggies. If you want to understand the background of this, read on as I will give you a bit more substance below.

It is important to know that the world population is projected to reach 9.7 billion by 2050 and that it has been estimated that 50% of the arable land around the world will become unusable for farming.

You hear a lot about climate change and indeed the drought and floods destroy a lot of our food, but also soil erosion and degradation impact the amount of food a farmer can grow. Over-usage of nitrogen and other chemical fertilizers ruin the soil and strip it of vitamins and minerals, becoming just dust. If you would like to learn more about the downfalls of traditional farming watch “Kiss the Ground” currently airing on Netflix.

 

This means that we have to find a way to increase food production by 110% from today’s level to meet the high demand for food as we currently know it.

Will Commercial Vertical Farming Help Us To Grow Enough Food For All Of Us?

A possible way out is commercial vertical farming, and I am sure you have heard about it. It’s a way of growing plants mostly hydroponically in vertical greenhouses near where you live. That has the added benefit of reducing CO2 due to short transportation distances and allows you to eat fresh, as the time from harvest to table is usually shorter than importing veggies.
 

You might have heard some people complain that veggies grown only in water aren’t as good as soil-grown. As with many things, people like drama and everything that’s new often gets first derided until people have learned about it.

Do rather have store bought or home grown vegetables?

The question you might want to ask yourself is, would you rather eat store-bought vegetables that come with more than 35 chemicals thrown in, or are you concerned that hydroponically-grown veggies might lack a mineral (something that has been proven not to be the case if grown under the right conditions)? I’d rather ditch the chemicals if you ask me.

Let me know get to a bit more technical detail on why hydroponically vs soil-grown veggies are just as good and destroy a few myths that are out there. The team from ZipandGrow have reviewed the research and made a good summary and I will share with you the details below:

ััYoung plant

What do you worry about?

What people tend to worry about is the micro-organisms in hydroponics compared to soil, after all we were all told that soil is rich on minerals, fungi and other micro-organisms that help our veggies to became so delicious and full of vitamins.

So does the hydroponic environment lack those micro-organisms and is it sterile?

Bacteria play a crucial role in nutrient processing and uptake by plants hence it is important for them to be present in order to produce high quality produce. The studies that looked at the microbiology in hydroponics systems found about 10,000,000 bacteria per milliliter of nutrient solution (1, 9) in comparison to compost which was found to have between 100,000 to 1,000,000,000 colony forming units (2, 3, 6). Note that comparing water to dry dirt is comparing apples to oranges, but it’s an indicator that the bacterial populations in conventional hydroponic systems are right in the normal range for compost which indeed is also rich in fungi. (9).

Are these micro-organisms as fast populating as the ones in soil?

Hydroponically-grown veggies indeed benefit form a microbial flora that is established very quickly. It was demonstrated that bacteria in a hydroponic system growing tomatoes in rockwool started with a nutrient solution that had 500-900 cfu/ml bacteria in it would get a bacterial population of 1,000,000 cfu/ml within 20 hours. The later analysis showed that the majority of these bacteria were the bacteria which aids the plant in defense and nutrient uptake called Pseudomonas fluorescens.

Does hydroponically-grown food has the same beneficial mix of diverse microbes as soil?

Not only are microbe populations in hydroponics high but they’re also just as diverse as soil ones. Research shows that the diversity in hydroponics is equivalent to what is found in soil (4).

Do hydroponically-grown plants grow as strong as soil-grown plants?

Let me introduce a word you might first need to master to pronounce, well it took me a bit. I am talking about – Mycorrhizae – which refers to the fungi that assist plants to stay healthy and support their nutrient uptake.  They are found on the roots of the plants, and they play a key role in plant growth.

Mycorrhizae thrive in hydroponics and often organic farmers use hydroponic systems to grow mycorrhizae to be used to support their organic soli farming (7,8).

How can roots grown in water develop the same health benefits as those in soil?

Our thinking comes from the way we were raised and educated. We traditionally learned that food grows in soil. What we tend to disregard is that food grown 30 years ago had much better health benefits than today’s produce, with less soil erosion and overuse of fertilizers just to name a couple of factors.

The importance is not in what roots grow, it’s about what is on the roots’ “skin” (roots’ surface) that is important for the plant. Reason is that the microbe population immediately surrounding the roots are much higher than the surrounding area which could be soil or water. The reason for this difference is because plant roots exude a substance referred to as mucilage—which is a complex mix of carbohydrates, amino acids, and organic acids and microbes just love that stuff.  These beneficial root zone bacteria in hydroponics were found to be in similar range as to what is found in soil.

 

 

So when you think soil, it’s mainly the roots and the bacteria growing right around it that organic agriculture relies on for the plants to thrive. So it’s less about the soil or the water the plants grow in and much more about the microbes that help thrive plants independent where they grow.

In Summary

I hope that this has been helpful in building on your knowledge and encouraging you to think independently from how we all used to view things some decades ago.

 

So what do YOU think? Are you a “dirt is good” farmer or do you prefer the benefits that growing hydroponically brings? Join the conversation and let us know!

References

Credit to ZipandGrow for their excellent research on this topic. This blog uses parts of the original copy that was published on https://zipgrow.com

1. Berkelmann, B., W. Wohanka, and G. A. Wolf. 1994. Characterization of the bacterial flora in circulating nutrient solutions of a hydroponic system in rockwool. Acta Hortic. 361:372–381.
2. Bess, V. 2008. Evaluating Microbiology Of Compost 83–85.

3. Chandna, P., L. Nain, S. Singh, and R. C. Kuhad. 2013. Assessment of bacterial diversity during composting of agricultural byproducts. BMC Microbiol. 13:99.
4. Chave, M., P. Dabert, R. Brun, J. J. Godon, and C. Poncet. 2008. Dynamics of rhizoplane bacterial communities subjected to physicochemical treatments in hydroponic crops. Crop Prot. 5:418–426.

6. Hassen, A., K. Belguith, N. Jedidi, A. Cherif, M. Cherif, and A. Boudabous. 2001. Microbial characterization during composting of municipal solid waste. Bioresour. Technol. 80:217–225.
7. IJdo, M., S. Cranenbrouck, and S. Declerck. 2011. Methods for large-scale production of AM fungi: Past, present, and future. Mycorrhiza 21:1–16.

8. Millner, P. D., and D. G. Kitt. 1992. The Beltsville method for soilless production of vesicular-arbuscular mycorrhizal fungi. Mycorrhiza 2:9–15.
9. Waechter-Kristensen, B., S. Caspersen, S. Adalsteinsson, P. Sundin, and P. Jensén. 1999. Organic compounds and micro-organisms in closed, hydroponic culture: Occurrence and effects on plant growth and mineral nutrition. Acta Hortic. 481:197–204.

10. Zaccardelli, M., F. De Nicola, D. Villecco, and R. Scotti. 2013. The development and suppressive activity of soil microbial communities under compost amendment. J. Soil Sci. Plant Nutr. 13:730–742.