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Juicy tomatoes in the winter? Thank hydroponics.


Be honest. When you hear the term “hydroponics,” you automatically think of — what? Growing marijuana, right?

“When I go home and tell people what I’m doing, they’re like, ‘Oh, hydroponics, you’re going to grow weed, right?’” said John Ertle, an Ohio State graduate research associate within Professor Chieri Kubota’s Horticulture and Crop Science lab. “That’s the typical reaction because what we do isn’t traditional agriculture.”

Kubota professor of Controlled Environment Agriculture within Ohio State’s College of Food, Agricultural and Environmental Sciences provides research that supports indoor and greenhouse farmers across the country. The base of the controlled environment agriculture industry is using hydroponics to feed and grow vegetables, fruits and berries within a controlled environment. This means locally grown produce year-round, anywhere.

“The idea you can control plant growth by manipulating temperature, light, wind and CO2 is just so fascinating,” Kubota said.

Fascinating, profitable and more healthful to people and our environment.

But first, what exactly are we talking about here?

How hydroponics works

Let’s start with our word of the day: hydroponics.

Plants need water and 13 to 14 different elements as fertilizers including nitrogen, phosphorous and potassium. In a hydroponic system, filtered water delivers the exact amount of fertilizers to the plants in the exact amount needed throughout the day.

“It’s very controlled, very efficient,” Kubota said.

There are different types of hydroponic systems or techniques. Three of the most common include:

  • A nutrient film technique uses channels, like slots, in a long gutter. Plants sit on top of the gutter and the water runs underneath, delivering water and fertilizers throughout the day.
  • A deep water culture system is essentially a pond filled with a nutrient solution. Plants sit in rafts with the roots sliding through slots, allowing them to absorb water and nutrients in the pond when needed.
  • A soilless substrate culture system is a bag or container filled with aggregate mix (rockwool, peat or coco coir) to which water and fertilizers are delivered as needed.

The greenhouse or indoor farm facility itself is a huge part of the setup, which is why engineering is critical to controlled environment agriculture.

The structure needs to be able to handle wind and snow and be optimized for sunlight. When the sun isn’t shining, LED lights turn on via an automatic sensor. Sensors also control heating, cooling and humidity to maintain an ideal climate for plants to grow.

What can be grown in hydroponics?

Eventually, and in theory, probably anything, but any new crop needs work and fine-tuning.

Currently, what is typically grown in controlled environments includes lettuce, kale, spinach, herbs, tomatoes, cucumbers, peppers and strawberries. Kubota, in fact, introduced hydroponic/soilless strawberries to the United States and hopes to work on producing raspberries and blueberries in the future.

Oh yes, and cannabis, though we’re not endorsing that … yet.

The benefits of hydroponics

Actually, there are a slew of benefits to controlled environment agriculture. But here are some main ones:

  • Open field farms use pesticides and herbicides to kill weeds, bugs and diseases. The use of those chemicals is limited in greenhouse or indoor farming, meaning the food is toxin free and there are no chemicals running into lakes or ponds near you.
  • Water consumption is drastically reduced. Many indoor farms recycle the water used in fertilizing. This means about a 90% reduction in water use compared to outdoor farms, according to Kubota.
  • Locally grown produce means fruits and vegetables taste better, last longer cutting down on food waste and are more healthful. Studies have shown vegetables often lose significant amounts of vitamins the further they travel.
  • Another significant benefit is to the U.S. economy: Controlled environment agriculture is a booming industry. According to the 2019 USDA census, there was a 132% increase in greenhouse production for vegetables and herbs from 2012 to 2017 in the United States. Many indoor farms require a spectrum of jobs: engineers, horticulturalists, biologists, chemists and those who work in manufacturing departments harvesting and packaging the products.