Maximum Yield USA 2015 October | Page 76

BIOPONICS: A STRANGE HYBRID Bio-filters 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 welloxygenated 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 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 A small bioponic set-up. 74 Maximum Yield USA | October 2015 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. 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! Electro Conductivity 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 NOT A LOT OF NUTRIENTS ARE REQUIRED TO ACHIEVE A NICE CROP IN A BIOPONIC SYSTEM.”