A catchphrase in our contemporary industry is “hybrid hydroponics.” While I have not found an agreed-upon definition for what this phrase means, I believe the heart of the concept refers to a growing trend towards the innovative combinations of multiple growing substrates and multiple irrigation methods to boost plant growth rates and maximize yields.
In other words, newer generations of growers are moving beyond the archetypical single-irrigation-method systems (e.g. flood and drain, drip, deep water culture, etc.) and embracing relatively new substrates to produce results closer to optimal yields than previous generations could achieve. Increased scientific understanding is a significant contributor to this trend, but an equal or greater amount of credit belongs to the technological development of new substrates.
Over the past few decades, a large number of materials have been developed as potential growing media or substrate amendments. Diversity and innovation reign supreme in this domain: raw materials like peat and pumice, recycled materials like glass and tires, processed materials like expanded clay and rockwool, as well as food and agricultural waste products like coir, bark and hulls and, of course, water are all used. Then, the number of possible growing media becomes infinite when you begin to mix the diverse materials together in various ratios.
Although growers can purchase effective commercial systems and substrate mixes, a lot of people are bitten with the do-it-yourself bug and prefer to create their own uniquely blended substrate from the multitude of possible ingredients. It can be enjoyable to put one’s creativity to the test by designing a unique soilless mix, but satisfaction ultimately depends on the yield and quality of the crops harvested from your mix.
In this article, we will glimpse the development of a hybrid hydroponics system that has been adapted from another. Along the way, we will look at a few significant factors that should affect your choice of mix components and discuss a number of practical procedures that will help to calibrate your fertigation decisions.
Case study: bio bucket 2.0
My motivation for creating an original bio bucket system came from reading an article called Hybrid Hydroponics with Bio Buckets by Casey Jones Fraser. In the article, Fraser discussed an innovative growing system consisting of a continuously running drip-deep water culture system that combines four different media in a mesh basket (i.e. rockwool, peat-perlite mix inoculated with beneficial bacteria, and expanded clay).
Though imitation is the sincerest form of flattery, it isn’t in my nature to waste any opportunity to add personal touches on any system. Why not experiment with the infinite combinations of irrigation methods and substrate composition?
In general, the systems I prefer to make and use have multiple irrigation systems coupled with only one or two substrates. The possibility of growing with such an inherently complex mix of ingredients seemed worth the time and effort if it delivers the expected high yields.
So, for this article’s hybrid system, let’s begin with the growing media components inside a 6-in. mesh basket. Fill the bottom 2 in. of the basket with a layer of large-sized pieces of rigid and highly porous glass foam medium, which will basically be submerged in aerated nutrient solution for the duration of the grow.
My greatest concern with the original bio bucket was the possibility that chunks of the peat-perlite mix dropping through the basket and into the reservoir below to potentially clog the pump. To safeguard against this possibility, and to make the eventual separation of components easier, let’s add a coco basket liner, which will theoretically wick a sufficient amount of aerated nutrient solution to constantly moisten the mix it contains. Within the liner, put a 50–50 mix of peat and small-sized glass foam pieces.
Guidelines and suggestions for successful hybrid hydroponics
So, we have now “built” our novel system and are excited to crank it up. However, we are more or less flying blind since we have little information for predicting its functional performance. It is one thing to grow with the individual components (e.g. media type or irrigation system) and get excellent results, but once multiple media are mixed and coupled with multiple irrigation systems, new dynamics emerge with unpredictable behaviors; in other words, there is an inherent risk of failure when designing and using innovative growing systems.
To mitigate your risk exposure to failure and increase the chances of getting high-quality large yields, I offer the following tips and practical procedures to aid your efforts:
Think big—Sometimes people create novel systems by throwing together whatever happens to be lying around or leftover from previous grow cycles. This isn’t necessarily the best idea. A worst-case scenario is that your plants will suffer and die because the properties of the media mix you created are out-of-balance and unknown. Another possible scenario is that you have excellent growth results, but you can’t duplicate the results because of the unknown mixture ratios.
Start small—A general rule in design and engineering is to add levels of complexity only after the dynamics of simplified system versions are understood. Translation: when attempting to build hybrid growing systems, begin by understanding how each type of medium will react with each irrigation system you want to incorporate. Once this is accomplished, build on that knowledge by combining two media together, and so on and so forth until the dynamics of the final system is understood.
So, for the bio bucket 2.0 described earlier, let’s say that my original plans called for a recirculating irrigation component. Since I hadn’t attempted to grow this particular media and irrigation combination before, I would begin by building a small, stand-alone prototype. If the results are successful and do not require further tinkering, only then would I add the recirculating capability.
Failure is inevitable and valuable—Another maxim of science and engineering is that failure cannot be escaped and we should we always try to avoid it. Often people who have a modicum of success in the early stages of system development become complacent about adding further innovations their systems.
Some believe the old adage “if it ain’t broke, don’t fix it,” and others might stop tinkering because of a fear of failure. The truth of the matter is that hybrid hydroponic growing systems are complex, and the chances of designing and building an optimal system on your first attempt are infinitesimally small. It is imperative to recognize that improvement is always possible and the chance of failure shouldn’t be a stumbling block. Through failure we can gain insights that success does not yield.
Success is knowing the properties of your substrates—Knowing the strengths and weaknesses of your media is of utmost importance. There are quite literally dozens of tests you can perform on your media to determine the properties of both the individual components and total mixed substrate. While a number of these tests require specialized, and often expensive, equipment to measure a particular property, many cheap tests can be done to an acceptable degree of precision to assure excellent growth results.
In my opinion, the variable of utmost importance is the air-to-water ratio, which refers to the relative amounts of usable oxygen and water a substrate makes available to plant roots. It is important to strike a balance in the moisture level of the substrate between moderate aridity and total saturation to avoid root death due to lack of water or oxygen.
As a rule, this can generally be accomplished by combining media with high water-holding capacity (e.g. coco, peat or rockwool) with media that have high air-filled porosity (e.g. expanded clay, glass foam or perlite). If you are looking for a greater degree of precision, a simple method for testing this ratio is to saturate your media mix, allow for complete drainage and then record the length of time it takes the media to dry to a certain standard (e.g. dryness at 2 in. depth below the surface).
This result will allow you to gauge how often you will need to irrigate the media, providing your plant with a stage-appropriate nutrient solution. So, whether you easily find success or struggle to make progress in your attempts at hybrid hydroponics, you should always bear in mind that the goal is to always learn from your mistakes and to build a better growing system.