When Hydroponics Meets Organics
Bioponics is a strange hybrid of hydroponics and organics—two approaches to gardening that are typically thought of as opposites.
Hydroponics is the practice of growing plants with a neutral substrate, or with just the plant roots bathing in a nutrient solution, whereas organic farming relies on soil as the primary source of nutrients for plants.
I managed to combine these methods in 2005 when I created bioponics, which involves the use of a certified-organic nutrient in a hydroponic solution along with a substrate, or even just bare roots.
With bioponics, it is possible to grow organic produce using hydroponic technologies.
Organic vs. Mineral Hydroponic Nutrients
Understanding how a bioponic system works begins with an examination of the main differences between organic and mineral nutrients. For this explanation, assume that the food source absorbed by the plant is the exact same in both cases.
When a mineral salt is dissolved in water, it dissolves in the form of an ion (an element with an electrical charge) that is able to be taken up by the plant immediately.
In an organic nutrient formula, the same mineral is enclosed inside an organic molecule. For the mineral to become available to the plant, the organic molecule needs to be broken down by bacteria or fungi into ions that the plant can absorb.
Soil decomposition is carried out by micro-organisms that are constantly present. Plants complete their diet by absorbing minerals coming from the decomposition of rocks, also dissolved in water in the form of ions.
To reproduce nature, a hydroponic grower has to use only two sources of plant food: natural rock powder and organic matter that was not treated with chemicals.
In a hydroponic system, when a grower wants to add organic matter, even in liquid form, to the nutrient solution as a source for plant food, they must replicate the same process that takes place in soil to break down molecules.
In other words, you have to introduce living organisms into the hydro system.
This additional life means an added level of complexity for you, the creator of this little biosphere, because micro-organisms cannot be controlled as easily and precisely as other aspects of an indoor garden.
Let’s take a closer look.
Microorganisms in Hydroponics
In a bioponic system, you need allies in the form of micro-organisms. How do you achieve that? One way is to let nature take its course.
Micro-organisms are always present in the environment. They are in the air, in the water, on us and inside of us. They are everywhere.
If you choose the natural route, the decomposition will be slow to start, and your plants may suffer until a reserve of nutrients builds up in the solution.
It is best to speed up the process by introducing trichoderma, a variety of beneficial fungi that colonize plant roots in a mutually beneficial relationship.
They are present in all healthy soils, but they are also well-adapted to survive in an inert substrate. Trichoderma do their job well, are easy to source and are not expensive.
Bio-filters in Bioponics
Trichoderma fungi need to cling to something to get established. If you use a substrate with a certain amount of coco fiber or any other organic material in it, no problem, the trichoderma will colonize it.
But if you are growing using clay pebbles, stonewool or any other mineral substrate, you need to use a bio-filter, which is simply a well-oxygenated space containing substrates on which micro-organisms can grow and reproduce. You can find bio-filters in every size and shape in aquarium shops.
They are usually placed on the tank, where a small pump draws the solution from the tank, circulates it in the bio-filter and cascades it back into the tank.
This added circulation on top of the main pump will be a source of extra, much-needed oxygen that will feed the organisms in the filter.
Over time, attracted by food and oxygen, other beneficial organisms will colonize the bio-filter, too, as well as the root zone, making the breakdown of organic nutrients even more efficient.
pH Levels in a Bioponics System
Even though pH levels in bioponics are less critical to a functioning system than they are in a mineral nutrient solution, you still have to keep your pH within the 5-7 range so roots and micro-organisms can thrive.
The pH will tend to rise naturally over time, which will require you to bring it down slowly to avoid shocking and damaging the microflora. Plants prefer stability, especially in the root zone.
To lower pH, use citric acid if you want to stay strictly organic, but a little phosphoric acid does not alter the taste or quality of the final crop. Avoid hydrochloric acid and acetic acid (vinegar), which are both harmful for plants.
A significant drop in pH may indicate the death of a large quantity of micro-organisms.
In this case, it is important to find out the cause of the drop, treat it and start over with a new solution and a new stock of trichoderma.
Electrical Conductivity in Organic Hydroponics
In a bioponic system, you need to keep the electrical conductivity at a much lower level than you would for a mineral solution.
This is because as long as the mineral is not realized from the organic molecule, it does not register on your EC meter. In other words, you have more food in your bioponic solution than the meter shows.
That being said, do not put too much fertilizer in your bioponics tank. A little goes a long way in these systems. You will notice that not a lot of nutrients are required to achieve a nice crop in a bioponic system.
Start with an EC of 0.6-0.7 mS, which corresponds to around 2 ml per liter of nutrients. Raise the EC over the course of a week to 1 mS. Add more nutrients if the EC drops below 0.8 mS, but don’t raise it over 1 mS.
You can also determine the optimal moment to add more nutrients just by looking carefully at your plants, their roots and the color and transparency of your nutrient solution.
Bioponics is managed by the eye as much as with pH and EC meters.
This step is all about balance, as a large amount of organic matter in the system might have a counterproductive effect by blocking roots. Just be careful to give your plants all they need without going over!
Other Parameters Affecting an Organic Hydroponic System
In a bioponic system, temperature, humidity, CO2 levels, lighting and all the other parameters of the growroom are similar to those for plants grown in traditional hydro or soil because the basic plant requirements remain the same.
The bioponic system and the nutrients you supply your plants are only one piece in a complex puzzle that you have to assemble to re-create a favorable environment for your plants.
Bioponics plays a vital role in the quality of the harvest, but it cannot compensate for a lack of illumination, depleted CO2 or bad genetics.
Humidity—a factor often overlooked in any garden—plays a crucial role in plant health. By influencing the rate at which a plant can transpire, the relative humidity level modifies the rate at which plants can absorb water.
The major enemy of bioponics, like traditional hydroponics, is heat, but in the case of bioponics, the consequences are different.
When the nutrient solution warms up, the microbial life increases tremendously in population and voracity and the amount of nutrients released increases tremendously.
As a consequence, the EC can go through the roof in no time, within 24 hours even, and this will kill plant roots. This is another reason why it is wise to keep a low EC when you grow in bioponics.
The Economics of Organic Hydroponics
Bioponics is an economical way to cultivate plants, as the consumption of water and nutrients is a fraction of what is needed by other growing techniques.
Bioponic production is based on the idea of sustainable agriculture. The goal is to give less nitrogen to the plants and shift the balance in favor of the flowering and fruiting stages, rather than the vegetative growth stage, which may be bountiful, but may end up being just another addition to the compost pile.
With bioponics, you do not need to change the nutrient solution too often during a plant’s life cycle—once every three weeks or even once a month is enough.
You can let the solution drop to a low level, minimizing the volume of solution to be renewed, just don’t allow it to accumulate too much organic matter in such a small volume.
When it is finally time to change the solution, don’t discard it. Instead, use it to water your soil-based plants. They will love the extra nutritional boost.
Protection Against Hydroponic Pathogens
The microbial population in a bioponic system becomes a formidable barrier against pathogens. In bioponics, roots are effectively protected by a huge army of beneficial organisms, so pathogens won’t be able to develop.
If you keep your system well-oxygenated, the roots will also stay immune to fungal attacks. But oxygen is really the key word here because everything in your system consumes it, both the roots and the micro-organisms. Consider adding a powerful air stone in the main tank to keep the solution well-aerated.
What About the Roots?
Remember that in hydroponics, root morphology is different than it is in soil. In hydroponics, plants develop what we call water roots, which are usually thinner and more fragile than soil roots.
Bioponic plants grow roots that are sturdier. Performing comparison tests between plants grown in classic hydro versus bioponics, I often found that root disease develops in the mineral-fed plants, but almost never in the bio-fed ones, even when systems are side by side growing the same plants. Bioponic plants are slightly smaller than traditional hydroponic ones, but they are definitely stronger when it comes to resisting root pathogens.
Quality vs. Quantity
In terms of quality, harvests from a bioponic system have the same taste and nutritional value as the best organic, soil-grown produce. It’s almost impossible to differentiate between the two crops, but I believe bioponic crops have a slight edge since bioponics removes a few of the barriers that limit plant growth.
And in bioponics, plants can express their full genetic potential. As with other gardening methods, your choice of plant varieties will have a major influence on your final results.
In terms of quantity, the yields will be lower than when growing using traditional hydroponics or soil, but your turnover will be much faster than in soil, so you can turn over more crops per year in a bioponic system than you could in even the best organic soil.
Since 2005, many growers, both hobbyists and professionals, have been experimenting with bioponics with continual success, and it’s rewarding for me to learn through their feedback.
In our research greenhouse, we are still using minerals for a certain number of tests, but we always have something growing in our bioponic system, and we are shifting more and more towards it. It is such pleasure to witness plants grow so healthy and so fast.
Give bioponics a try and I am sure you will not think of hydro or soil in the same way again.