Cultivating Crops for High Yields with Aeroponic Systems

Aeroponic growing has gained popularity for the ability to produce healthy, fast growing and heavy yielding crops without the use of any growing medium or substrate for roots.  Rather, aeroponic plants are supported outside aeroponics systems with bare roots growing inside of the system. The roots are periodically misted with a nutrient rich spray or fog.

Because there is no growing medium in between the roots and the fertilizer formulation dissolved into the water, crop roots have direct access to oxygen, water and vital elements. The result is very fast growing and healthy plants that use a fraction of the water of conventional growing methods due to the extremely efficient water and nutrient delivery system.  Additionally, the sprayed nutrient solution is drained away, collected and reapplied at timed intervals.

Note that many of the systems promoted as “aeroponic” may not fit the definition as described above–that’s because they do not actually mist or fog roots. Instead, they deliver coarser water droplets by splashing water around roots.  While it may sound trivial, it’s not.  A fine mist or fog has considerably more surface area when delivering nutrient rich mists to bare plant roots. A typical High Pressure Aeroponics cycle may only last a few seconds, with anywhere from 4 to 20 minutes typically between each cycle. A single root chamber in such an aeroponic system may only be delivering a few ounces of nutrient solution per cycle.

For home hobby gardeners this may not be an important point of difference for aeroponic growing.  However, for the serious small to commercial scale grower the difference is significant in the ability to manage the system and achieve the best results possible.

At Grozine, we have recently begun to cultivate greenhouse crops using High Pressure Aeroponics (HPA).  While the aeroponic growing system is somewhat “experimental”, we have grown a variety of cold and warm season greenhouse crops since setting up our aeroponic growing system. We set out knowing that the systems were excellent for producing rooted cuttings or starting seeds.  Growing aeroponic crops to full term was a new endeavor. 

So YES, it can be done!  Additionally ,we are very pleased with the results, both for crop quality and from a cultivation management perspective.

Here’s What We Have Learned So Far:

Aeroponic growing systems are super lightweight.  

You don’t need tons of support for the aeroponic chambers.  Really, you just need to be able to support the weight of the crop, which can be accomplished by trellising. The big advantage here is lower cost due to less materials needed for supports and fast set-up times with considerably less labor. The lightweight nature of the modules beckons us to stack them for vertical growing.

Professionally designed aeroponic systems are reliable. 

Previously, this was a worry: “what happens if a mister clogs, or the power goes out—there’s nothing for the roots” Turns out that not a single mist/fog nozzle has clogged and we’ve been without power for a couple hours here and there due to storms, etc and had no problems.  During hot sunny weather this could get dicier, but so far we’ve been lucky.  There’s always power back up options available too.

Additionally,there are some fail safes built into our aeroponics growing system, for example an in-line filter in the aeroponic delivery manifold and protective screens built into the fogger nozzles themselves.  NOTE: it is important tio use 100% soluble fertilizers intended for aeroponics for smooth system operation and great cropping results.  We recommend Cultured Solutions.

Aeroponic crops are fast growing and hardy.

We wondered if the plants might be on the frail side with roots suspended in air inside of the aeroponic growing chambers. Afterall, the greenhouse is an intensive environment with limited climate control (compared to indoor growing).  We’ve grown crops during peak summer months as well as in the snowy winter months, here in the Canadian Pacific Northwest. Plants are exceptionally healthy and fast growing and do not appear to run into water deficits. We can keep the rootzone conditions closer to optimal temperatures by heating or cooling the nutrient solution reservoir that supplies the individual aeroponic chambers. 

The principles of Thermodynamics add a level of efficiency.  We can maintain hotter or colder than desired air temperatures in the greenhouse (saving power) because the plants are cooled or heated directly through the roots via nutrient solution delivery.  Remember, plants are around 90% water as fresh weight!

Plants tolerate higher fertility levels in Aeroponics.

Growing in aquaponics, we have found that plants do best with a slightly stronger crop feeding regimen. This is likely due to the fact that plants are exceptionally healthy and have the ability to produce sturdy growth quickly.  Naturally, this takes building blocks by way of crop fertilizer to accomplish.

High Application frequency with small root systems, lower frequency with larger root systems.

This part was a little counter-intuitive initially. Turns out that the bare roots act as their own growing medium of sorts, as they get covered with a fine layer of nutrient and oxygen rich water droplets with each irrigation spray application; the more roots, the longer the relative retention ability to a degree.  Fresh transplants with small root systems require more frequent applications to keep young crops hydrated. We start at 4 minute intervals with 20 second delivery times and gradually increase the dwell time to 20 minutes while still retaining 20 second delivery times.  By no means is this an absolute or even a good “rule”; we just find that it works for us.

Aeroponic harvests are of higher quality with a long shelf life.

Everything we have tasted from our aeroponic growing system has been exceptional.  Our Genovese Basil has been extra pungent and oily while our Kale has been extra sweet, mild and crisp. Plants are very vibrant at harvest; they aren’t “winding down” like with conventional methods at maturity.  This seems to create an extra long shelf life when refrigerated (while retaining a higher standard of quality)

Water & fertility management are simplified. Automation is easy.

It’s easy to monitor or adjust conditions in the system via the remote aeroponic reservoir, whether checking pH, EC, TDS, Temperature, ORP, etc.  There appears to be very little difference between what happens at the roots versus what is measured in the reservoir–although the solution can heat up slightly in the aeroponic manifold delivery piping with longer dwell times during warm weather (simply cool the reservoir more).

Controlling air to water ratios in the root zone is as easy as adjusting the aeroponic pumping cycle; no tedious dry back calculations, etc required as with some types of growth mediums.

Professional aeroponic systems are not cheap to buy, but operational savings add up quickly.

Very little power is required to operate the system, as the pump only cycles for 20 seconds at a time, and with not much frequency. Heating or cooling the aeroponic reservoir (remember thermodynamics) saves on heating or cooling the entire greenhouse environment.  Additionally little to no water is wasted as the system is sealed–whatever water is depleted is used directly by plants (no growing medium is exposed). 

The fact that we can grow very high density plantings with just starter plugs or net pots means we aren’t constantly handling, purchasing, or disposing of growing mediums which is very costly; both to us and the environment.  Naturally, the transplant labor is a fraction of what conventional growing methods require (potting, handling or pre-treating cubes, etc)

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