Are Plants Grown Hydroponically Organic? The Dirty Truth

Brock Ingham

This post follows our research editorial guidelines.

Brock Ingham

At first glance, it might look like high-tech hydroponics and eco-focused organic farming couldn’t be further apart. One is all science and numbers, and the other all soil and sun. Surprisingly, there are areas of significant overlap. Both systems aim to improve food systems and provide for the hungry in ways that are sustainable and environmentally sound. Hydroponic seeds spend their life growing just the same as those in other systems. But are these two practices compatible?

Hydroponic Chard
Hydroponic Chard

Can Hydroponics Be Organic?

Hydroponic systems that meet the guidelines for organic certification can be legally labeled ‘organic’ in the United States. It is however not without controversy and some believe that no system without soil can ever be called organic.

What Does It Mean When a Plant Is Organic?

‘Organic’ when it comes to plants refers to how it was grown. It can only use naturally occurring fertilizers, pesticides and growing practices. That includes the substance in which they grow, and for most of the world that’s soil. In fact, many organic growers consider the overall health of the soil to be the foundation for their practice.

In the US, the United States Department of Agriculture sets the standard for what producers need to do in order to be able to call their crops organic. There’s many different standards around the world, but all share a common understanding around sustainability and the importance of soil.

Is Hydroponics an Organic Form of Gardening?

The simple answer is that if you only use naturally occurring fertilizers in your hydroponics system it can be considered organic, as far as the USDA certification process is concerned.

That simple answer hides a lot of complexity. In other parts of the world plants must grow in soil to be classed as organic. Only the USDA standard allows plants grown without soil to be considered hydroponic.

This obviously presents a problem to the hydroponic grower. While it’s totally possible to run a hydro setup with no synthetic inputs, all hydroponics focuses on soil free growing. It depends on where you personally stand as to whether or not you consider hydroponics truly organic.

Basic Principals of Soil-based Organic Farming

Soil-based organic farming stresses the importance of soil ecology . It encourages the addition of organic matter to farmland in order to regenerate and support the living soil – that’s the ‘organic’ that gives its name to the practice.

Manures, green cover, mulches and the like are used instead of synthetic fertilizers. Microbes in the soil break them down and turn them into nutrients that can be accessed by the plants.

This material does more than just add fertility. It also improves the overall structure of the soil. It encourages beneficial fungi and bacteria, increases the amount of water it can hold, and protects against erosion.

All other inputs also need to meet standards. Weed suppression, pest management and disease control must be managed without synthetics. Organic growers do this using what’s called the ‘PAMS’ strategy – Prevention, avoidance, monitoring and suppression. Chemical options, from a list of acceptable choices, are the last resort.

Basic Principles of Organic Hydroponics

Deep water culture lettuce
Deep water culture lettuce

In contrast, organic hydroponics understandably pays no attention to the soil. Fertility is provided in readily accessible liquid form, as a nutrient solution. Where that fertility comes from is the tricky part – most nutrient solutions are synthetic. But it’s possible with a bit of work to find organic options.

The first is to use a commercially available organic nutrient solution. These are generally made by carefully fermenting natural plant material with bacteria similar to those found naturally in soil. Others come from naturally occurring minerals.

Other organic hydroponic systems cut out the middle man and harness the microbes themselves. For example, aquaponics systems use microbes to break down fish waste and turn it to fertilizer. Feed the fish organic food and everything coming from that system will be organic.

Other organic farming practices are also maintained. In fact the nature of hydroponics makes some aspects easier. Organic hydroponics growers don’t need to worry about weeds, and indoor growing cuts down on other pests.

Why is Organic Hydroponics a Controversial Topic?

Plenty of folks believe that if there’s no soil involved there is no justification for referring to a system or its crops as organic. Improvement to the soil is a criteria in almost all certification systems world-wide, after all.

“Hydroponics in organic is not permitted in the rest of the world, nor is it endorsed by the U.S. organic movement, nor is it supported by the law. It is time to fix this.”

Dave Chapman, founder of the Real Organic Project, plaintiff-appellant, Center for Food Safety vs. the United States Department of Agriculture.

Only in the US are exceptions made for hydroponics. This resulted in a group of organic growers challenging the USDA in court. Repeated court cases over many years have consistently ruled that as long as they adhere to the rest of the standard, plants grown without soil can be labeled ‘certified organic’. The most recent ruling, the 2020 case of Center for Food Safety vs. the United States Department of Agriculture, has only further cemented this position.

While plenty of ardent organic growers consider this to be a violation of the spirit of organic farming, others find common ground with hydroponics. Hydro fans frequently embrace a  similar philosophy of sustainability and environmental stewardship.

Hydroponics uses less water and can grow food close to the plate, reducing land use and the energy needed to transport. It’s also a great avenue to recycle agricultural waste like rice hulls or coco coir, and many systems can be built from trash. Close systems prevent runoff and environmental degradation, too.

Organic Hydroponic Feeding

Hydroponic Nasturtium
Hydroponic Nasturtium

The key tactic to organic hydroponics is managing your nutrients. No nutrients and you will see no growth.

The easiest way to achieve an organic system is to use a solution that was produced naturally. Most organic solutions will be clearly labeled with organic certification, usually in the form of a seal located somewhere on the bottle.

You can always get the microbes working for you directly. Aquaponics is one of the few that can be reliably done with purely organic inputs that are cheap and readily available. It’s also a great way to provide organic seafood and salad right to your table.

Organic Hydroponic Pest Control

Thankfully pest control is one area where organic options are considerably more straightforward. Picking pests off by hand is one hundred percent natural and completely organic certified in all certification standards. If you have a large hydro setup, releasing predatory insects is also acceptable.

Organic Hydroponics and Algae Control

Algae control is another area where chemicals are often used in hydroponic systems. But the PAMS principle applies here, too.

To prevent algae, use opaque and dark-colored grow trays and reservoir tanks. This cuts down the light inside and limits growth. Avoid placing them in well-lit areas, too. Monitor the interior conditions as needed and suppress the algae by keeping the solution acidic and cool. You can also physically scrub it from tanks and trays between crops if the above doesn’t work.

Biggest challenges with organic hydroponic growing systems

Growing with organic hydroponics has its own challenges. Because organic solutions often still contain live bacteria, they can behave unpredictably. Some elements may be hard for the plants to access, or you may lack critical nutrition. It can be tricky to monitor the solution too. But with practice, it’s possible to achieve results similar to other systems.

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