High Pressure Aeroponics

High Pressure Aeroponics

It has been a while since I posted on the forum, but I recently got interested in High Pressure Aeroponics (HPA). I have searched many forums, perused posts from some of the giants (Fatman, and others I don’t want to put out there) and I have tried to construct a viable plan for the assembly and implementation of a high yield, optimal, indoor system. I have had great success with DWC (Deep water culture), RDWC (Recirculating DWC) , and LPA ( Low-Pressure Aeroponics- sometimes called Soak-a-ponics), but all of these systems are time, resource, and labor intensive. The lack of accessible cohesive resources has prompted me to seek the experiences, knowledge, and wisdom of growers here, to build a repository for future growers exploring the benefits of Aeroponics. I will attempt to outline a scaffold of a simplistic high-pressure Aeroponics system with the hope that growers that are more knowledgeable will contribute, redirect, and explain the science involved. Please feel free to add to this discussion, correct and excuse any nonprofessional fallacies, and maintain decorum, as this is an instructional posting.

HPA simplistically utilizes a fine mist of water and salts, approximately 50 microns in diameter, to wet the roots of a plant in a uniform fashion. This application provides the nutrients and hydration for optimal assimilation and subsequent integration into biomass. Provided at specific intervals and quantity, in association with adequate photosynthetically active radiation (PAR) and climate controls, plants will grow to their genetic potential. Constructing a system to attain said environment is attractive to hobbyist and professional growers alike.

The basic ideology of an HPA system is that a reduced nutrient solution, low parts per million (PPM) solute, is pressurized to 80 PSI or greater, and aerosolized to fine droplets. These are absorbed by the plant, in addition to requisite oxygen, to provide resources for growth without input of energy from the plants, as they are readily bioavailable. Creation of said system is feasible and affordable with current technology.

Nutrient solutions are pumped at 80 PSI or greater through a misting nozzle directed at the roots. Optimally, the mist saturates the root zone and provides humidity and nutrients to the plant. Timed at specific intervals, the plants are afforded water, macro and micronutrients, oxygen and environment that reduce disease. A booster pump, spray nozzles, and short-cycle timer are the basics needed to begin creating a HPA system.

Some of the nuances integral to these systems are: nutrient schedules, nozzle size, mist timing, and redundant fail-safes. Throughout my research, I have encountered many unanswered questions. Some of these will be found through empirical evidence, others by serendipity. I will post my findings as time allows. To be continued…

I ran a HPA thread here about 5 years ago. Some smart people contributed

It is extremely sensitive to ambient temps and humidity, and does no work well in my environment

good luck

Hi PetFlora,
Thanks for the post, I would love to pick your brain. Can you post a link to your HPA thread, the search here isn't too specific, and there is a lot of unrelated threads to read through to get desired information? I'm trying to gather as much information as possible.
I have been pricing parts and viewing YouTube videos trying to ascertain what will work best with the least expenditure. I have had some promising results while bargain shopping for the parts to create the system. It's been fun and frustrating at the same time. I'll continue to update throughout the research and assembly of what I hope to be a very efficient and resilient system.
Thanks again,
ZXC

No clue. You'll just have go mining in RIU archives around 2013

Frustrated, I left HPA and developed a modified version of F & D, which has high rewards with a lot less hassle

One big key is to go with totally sterile nutrient profile

hth

After researching various systems, I came up with a plan to create a 3/8” system that uses small orifice TEFEN nozzles and has a large pressure reserve. I have omitted the connectors, fittings, and tubing from the following purchase list, but the essentials are here:

Aquatec Pressure Switch 100 psi shut off 3/8" (This is adjustable from 90 - 125 psi)

BACOENG - AC 110-120V 160PSI 5.1L/min -High Pressure Water Diaphragm Pump

DIGITEN 24V 3/8" Inlet Feed Water Solenoid Valve Quick Connect

Well-X-Trol WX-202 Well Tank (20.0 Gal Volume) (150 PSI working pressure)

Timer Outlet, Nearpow Multifunctional Infinite Cycle Programmable Plug-in Digital Timer Switch With 3-prong Outlet for Appliances, Energy-saving Timer, 15A/1800W

John Guest Acetal Copolymer Tube Fitting, Imperial Single Check Valve, 3/8" Tube OD

TEFEN - White Plastic 1GPH Nozzle W/Poly Filter Push Fit Tee 3/8" & Mounting Bracket



The idea is that the system will pressurize a larger volume of nutrient solution so that if there is a pump malfunction, the tank reservoir will provide hours of pressurized solution to maintain the plants. The detriments to this configuration are that more nutrients will be needed to run the tank. This is totally acceptable to me because I mix the raw salts and it only costs pennies to make nutes. This would be a serious consideration for a grower using a bottled mix, and a cost-to-benefit ratio should be determined.

Considering redundant fail-safes, I am entertaining splitting the pumping function with a 24VDC pump and separate 24VDC solenoid plumbed in parallel to the AC pump, but containing a 24V battery reserve. This secondary system would actuate if a power interruption occurred. The backup system would extend the emergency irrigation timeframe to days.

The other major concern I have found through research is the clogged-nozzle issue. As I perceive it, there is juxtaposition between optimal misting and over-misting. If the system is dialed in to optimal spray and evaporation times and there is a nozzle failure, plant loss will occur. Incorporating a redundant nozzle system will either oversaturate or limit oxygen absorption, and therefore reduce the efficiency of the system, but it will provide a layer of protection. Additionally, there are microbe problems that can arise from oversaturation/reduced oxygenation. These are considerations that will be addressed when the testing phase occurs and/or experimentally.

I’ll conclude the posting here, for now. I’ll add more as the project continues. Additional thoughts or modifications are always welcome. Happy growing and learning!

- ZXC

a sterile rez should prevent filter clogging. My mist heads had screens in each, which constantly got clogged. I resorted to placing an inline filter which was much easier to access and check and clean the filter

I forget the company, check irrigation filters, but this one is an inline push type (quick release)

Thanks PetFlora!
I did find one of those screen inline filters, it has a steel mesh chamber, I not sure of the pore size. I'm not sure if the TEFEN nozzles that I purchased also have pre-filters, I did get the no-drip type which has a kind of built in check valve. I have used beneficial bacteria and fungi in prior solutions, but I think I will omit them in the HPA system to reduce micrometer particulates. Good call!

Vertical height constrictions have limited past grows, so in this system redesign I’m going to try to make use of horizontal space. The buckets and totes have worked, but seem to waste a lot of room between units and the roots become bound in a clump. I had an epiphany while I was exploring a local hydro store.

On the side wall, in a tidy display, there was stacked flood trays. The 4’ x 8’ white tub caught my eye. The perfect size for my 9’ x 5’ Gorilla tent, and only seven inches tall. Instantly I assembled the unit in my mind using two of these, one flipped over the other, and reinforced with PVC to stop the middle from sagging. The PVC supports can double as tubing for low-pressure nozzle heads and provide a substrate for additional high-pressure nozzles. This just might be the perfect configuration for six to eight plants.

Prior grows have filled the seven foot tent to the lights, regardless of free standing or SCROG training. I’ll gain a foot of vertical height and utilize the space that was in between the totes. A chicken wire matrix suspended horizontally and intermittently will train and direct the roots to fill more of the flood tray. A slight angle on the tray will drain the area. I’m debating on recirculating the effluent or sending it to waste. Either way this should improve the design, and look pretty bloody cool.

More to follow…

- ZXC

the whole concept of hpa revolves around sufficient root space as well as space around each root mass for complete misting

The root space needs to be big and long: think 2 basketballs per plant

AND...

you do not want any roots resting in solution. DTW is a must, or forget it

Some have put hammocks or screens above the bottom of the root chamber to prevent this

This means losing minimum of 2ft height, just for root chamber

hth

Thanks again PetFlora. My thoughts about addressing this are included in my next post, but I know, I know... if I only had a higher ceiling. I did contemplate breaking up the cellar floor and putting in a four foot pit. Needless to say, it did not go over very well (no pun intended). Maybe the following system will accommodate some of these issues. I do intend to create a type of hammock system to keep the roots out of the solution. Thank you again, your knowledge is much appreciated!

The proposed system is probably going to draw criticism and chastisement from many, especially from purists. Here goes… I’m going to hybridize high pressure (HPS) and low pressure systems (LPS). (Reminding anyone of advanced Kama Sutra; sounds like a lot of fun, but you could get totally F’ed?) This is the basic concept, sans scientific abstract.

Most of the literature warns about system failure. Difficulties with nutrient profiles, humidity, temperature, and flow are a few. Combining the two systems should alleviate most of these while making moderate gains in growth rates. The ½” PVC support skeleton that is positioned inside the tub is connected to a low-pressure pump. It sprays the top of the roots for 2 minutes every hour. The bulk of the nutrient solution runs down the tray and recirculates to the reservoir, which houses the pump. This is positioned outside the tent to maintain temperatures ~ 60F. High-pressure nozzles are positioned along the underside of the PVC pipes. The system is actuated for a few seconds every five minutes. Excess spray accumulates in the tub, which will combine and recirculate in the LPS. The nutrient profiles of the HPS and LPS differ, but upon combining, they should normalize. This will be monitored for pH, temperature, and TDS (total dissolved solids in parts per million).

The HPS nutrients will be less concentrated; 200 to 400 ppm. It will contain standard NPKCaMg and micros, and will be adjusted continuously to accommodate growth, photoperiod, and deficiencies. The LPS will be more concentrated and contain additives. In addition to the standard profile Silicate, Humic and Fulvic acids, Seaweed extract, Chitosan, bacillus and mycos will recirculate. Ammonia and carbohydrates not listed will not be introduced. Effluent from the HPS should not change the concentration drastically as absorption and evaporation are in competition. Excess salt accumulation is addressed by the hourly LPS “wash”, which is monitored and adjusted accordingly.

The proposed system should account for the majority of the aforementioned detriments. Nozzle failure and/or dehydration are reduced by redundant dual systems. The maximum system downtime is increased by the hourly hyper-saturation. The likelihood of evaporation-induced nutrient burn is also reduced by said wash. Root zone heat is moved out of the environment with the wash and dissipated by the LPS reservoir. Pathogenic organism reduction is achieved through competition and cellular modification. The identified drawbacks of this configuration are sub-optimal water delivery and increased water requirements. These are acceptable considering the gains.

Thoughts are welcome,

ZXC

The low pressure system is contraindicated, negating the benefit of hpa

The methodology behind hpa is to barely wet the roots so that they become needy for more in a short period

If running a pressure tank and solenoids (I ner did) you can cut o/o to ~ 1 second/5 seconds

Use fulvic only for hydro

hth

PetFlora,

I read that the two systems were incompatible when I was reviewing the literature, but I didn’t find any good studies or data. I need some empirical evidence, and you just know I’m gonna try it, I’m dumb like that. I have experiment with the timing, but I have a rough starting point. Now all in need is a control group, damn it. Oh, with the accumulator I should be able to have short o/o timings, nice. I’ll need to see what works best with various nozzles. I have 1, 1.5, and 3GPH nozzles, which I figure I’ll need to change as biomass increases.

In regards to the humic acids, I figured that the roots would preferentially uptake the fulvic acids while the prokaryotic flora might utilize the higher m.w. humics. The heavier ions should chelate and be more bioavailable either way. That was a good point about the hydro systems, as they normally don’t breakdown molecules the way soils do.

On a side note, I checked out your link to the LED’s. Some pretty good stuff there. I did notice that the first few pages were brutal. I was impressed with the way you handled it, you are patient and pleasant. Thanks again for spending some of your time and wisdom here, always appreciated.

- ZXC

It's your party

When I was experimenting with hpa, one guy who ran large hpa system kept nagging me regarding the necessity of using a storage tank and solenoids.
I felt I could get in the ballpark without the extra complexity, and did, but only in the cooler months. Otherwise, the root chamber humidity and heat was too warm for root hairs to develop

HPA only works optimally when the amount of nutrient mist barely covers the root hairs and is readily available to be taken in. Over wetting causes the feeder cells to close up shop. To them its like a heavy rain

Dialing in the correct fed/pause cycle is critical. Although I did get lot of root hair roots, I never dialed them in as I would with a storage tank and solenoid, which is needed to get feed times under 1 second



hth

This just arrived today. I was supposed to get the 20 gal but it was out of stock, so I got this 26 gal jammy, It still has 125 psi working pressure, but it will probably only need to be filled once every day and not drop below 80 psi. Oh, the little guys are OG Kush that I just started, these little guys have seen light for less than a week. I figure I'll clone them up and be ready to try this experiment by March.

I'm defiantly going to have to dial in the timing and spray. With a bunch of experimentation I'll try to find the best compromise between the two systems. e.g., maybe LPS for 3 min/4hrs and HPS 1s/4min. I'm not sure, I have ideas from posts, articles, videos, but nothing concrete. It's going to be a lot of trial and error. I'll keep posting progress as the build/experiment continues and we'll see how it goes from there.

The OG kush seeds were procured last year, so I put three seeds in rapid rooters with the hope that one or two would germinate. They are supposed to be 28% THC, genetically female, 75% indica/25% sativa, with a 500g/m2 yield indoors. I have had great results with these in the past. Because these were a year old (or more), I put them in R.O. water@ 90oF submerged for four hours. After that I put them in to rapid rooters and covered the hole with a ripped off chunk to stop evaporation. These were placed into a microbiological incubator set at 85oF. Within three days 100% germination occurred, psyched! Once they emerged three 18w standard LED house light bulbs lit the incubator. These lights were not very strong, and stem elongation started, so I switched to a 125W CFL.

As of today, two sets of true leaves have emerged. They are in a dome humidity hood, and placed under the 125 CFL at night and in a solar room during the day. The CFL bleached the leaves a bit, and was raised to 18” from the tops. The rapid rooter plugs were placed into 6” net pots and filled with expanded clay. About 3 cm of the stem was buried in the clay. The net pots are watered once or twice a day when the pellets appear dry. The first three days tap water was used, thereafter a 270 ppm pH 5.6 nutrient solution was sprinkled on (approximately 50mL, which drains through).

The nutrients consist of Jack’s Hydro (I didn't want to mix from scratch for this weak solution) - 170ppm, CaNO3 - 40ppm, MgNO3 - 25ppm, K2SiO3/H2KPO4/HNO3 to pH and increase TDS. Seaweed (extra K), Humic/Fulvic acids and Fungal Mycorrhiza. This solution was initially applied followed, by tap water for the next watering. The nutrient then water cycle continued for a few days. When the leaves have matured a bit more the nutrient solution will be used exclusively. I’m now just waiting until they have emergent roots from the net pots to put them into a LP Aeroponics chamber.

Snow day today, my AP Chem students are happy. A bunch of stuff was delivered and I’m pretty excited. I have the pumps, pressure sensors, TDS meter, solenoids, timers, pre-filter, nozzles, tubing, AC/DC converters, check valves, and fittings. I’m waiting on a few fittings to connect the well tank to the pumps, but aside from that I should be able to start preliminary testing. There is one thing that is troubling me, though.

I wanted to create a parallel 24 VDC backup system in case of power failure. I purchased a 24V pump; the Aquatec CDP 8855, a 24V Aquatec Pressure Switch 100 psi shutoff, and a 24V solenoid, but I don’t have a 24 VDC Aeroponic timer. The timer that I have is the NEARPOW Timer Outlet, Nearpow Multifunctional Infinite Cycle Programmable Plug-in Digital Timer Switch With 3-prong Outlet for Appliances, Energy-saving Timer, 15A/1800W, and it is 110 VAC. So it looks like I’m in a bit of a quandary. Is there anyone who knows of such a thing and is willing to help me out? Aside from that, I’m in pretty good shape to get started.

If you scrutinize the pics, you will notice that there is a ton of 1/2” PCV fittings in the cardboard box. Yup, just what I need to start making the skeleton for the LPS and root zone container. I purchased these from PEXuniverse.com, and they were way less expensive than Blow’s or Home Cheapo. I’ll pony up and grab the PVC tubing from either of them, but the fittings…Hell No!

So, I’m on my way. Maybe I’ll get a free minute to work on this come spring break…

- ZXC

So, I just banged out a search for the 24VDC timers, and I found a few out there. I think I'll snag a 24V battery (preferably Li-ion) with a 110 vac constant trickle charge. I'll wire a normally closed 110 vac relay to the main system and piggy-back the DC system onto it. If the power drops, the relay will open, energizing the DC system, powering the back up system. One detriment will be that I have to keep the timer constantly powered. (I might be able to accomplish this by siphoning from the trickle charger.) Theoretically, if there is a grid failure, the relay will open, engaging the DC system and maintaining the HPS sprayers at their set intervals, as the DC solenoids will actuate with the timer...(maybe two relays to keep the solenoid from actuating needlessly...) Additionally, the LPS will be off-line and there could be accumulation of effluent that would be detrimental to the system in the event of a protracted outage. I can't foresee a pathway to circumvent this, but I'm open to suggestions. I'm brainstorming here, so bear with me. Furthermore, historically, the area in which I reside does not have extensive power outages, so this might all be for naught, but it is nice to have piece of mind...
...sorry guys, I have issues. I the words of Jim Carrey, "Somebody stop me!"

- ZXC

Hey guys,

So, I’m about six days into the seedling stage with the OG’s that were started. The solar room is pretty chilly ~ 60-70F, depending on the time of day. The house is also about 70F, so I’m a bit below optimal. I decided to add a 300W full spec LED to the tent. I didn’t want to waste watts on heat, so I hung the LED about 2’ from the top leaves. This addition brought the tent temperature to 83F, (I wanted 86F), and the leaves sprung up overnight. The relative humidity (RH) in the tent is about 80%, the seedling hood is about 85-90%.

I really want to reduce the RH so that transpiration will carry more nutrients to the leaves, but I’m a bit ashamed to admit that when I put my face into the tent, that warm sweet air makes me want to curl up next to those little guys. Maybe I can keep them small forever… anyway…Ahh! Harrumph …I’m huge, “I Kill You!” and “I’m awesome” !!! - - - Manhood intact, I’ll continue.

My next task will be creating a mini-aeroponics system to grow the seedlings to veg. I’m contemplating using a high-pressure pump in a small tote so that I can maintain portability, maximum growth, and secure nutrient profiles, in order to reap the benefits of natural light while maintaining a 24h light schedule. I need to transport the system from the tent to the sunroom twice a day, yet stay within feasibility parameters, all the while reducing my gross electric usage. Additionally, I believe that the full spectrum sunlight will stimulate uniform growth. This will be key when I am selecting shoots to clone.

So, this is the plan if I can pull myself way from the seedlings. I’ll keep you posted. Thoughts and comments are always appreciated! Grow on,

- ZXC