A Tale of The Tape HPA vs 21st Century Flood and Drain

This Journal is a tale of 2 distinctly different hydro methods= High Pressure Aero and what I call my 21st Century Flood & Drain. I think you will find the latter to be extremely simple with the potential for outstanding results.

I am using the same DM nutes in both, mixed as a single batch then dumped into the respective rezes. Grow ppms @ 420 Once I flip ~ 600 and NO more than 800 at full bloom. No bloom boosters needed, or wanted, though during flower I add a bit of DM Potash+.

I have been working through HPA (high Pressure Aero) for 5 grows. Now on my 6th, and all is well- Finally!

HPA was developed by NASA to feed astronauts on space stations. It is the most efficient method in that it uses no soil or medium AND it uses a very small amount of liquid nutrients delivering them under pressure (~ 60-120 psi). The nutes are pumped from a separate rez through high pressure tubing into small mist heads creating an atomized mist with a droplet sizes ranging from ~ 30--80 microns. Each feeding is < 1 second roughly every 1-2 minutes, depending on ambient conditions.

Roots fed this way look nothing like any other roots. First they are loaded with lateral roots (fish bones). When the RH inside the pod is optimal, each fish bone grows root hairs (think pipe cleaner fuzzies). The massive surface area created by the fuzzies provides maximum nutrient uptake. The root photos are not quite dialed in

Root Pics 5 days ago. Still dialing wt cycle in. Currently 1 sec on/1:55 seconds off during lights on; 3:55 off during dark cycleIMG_0940.jpgIMG_0942.jpg

Most HPA growers use a sophisticated system, including pressurized storage tanks, pressure relief valves, pressure gauges, and solenoids to perfect the amount of atomized nutrient during each wet cycle.

Since my HPA roots can be similarly efficient, I chose not to carry my idea to their exacting standards. I use a hpa pump (Aquatec 8800) + a Sentinel Digital Timer, which is not 100% accurate @ 1 sec wet cycle intervals. When the RH inside my pod is conducive, I get root hairs, but due to not having a controlled grow room environment, root hairs are hit and miss. Still, my hpa roots provide considerably more surface area (to slurp up nutes) than any other method. How important that is, we shall see.

Now, hpa has been a RPITA (mostly pilot error), but I am confident my simplified version will produce excellent results.

HPA pic taken 4 days ago


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During my last hpa grow all seemed well. The plants looked really healthy until I cut the light cycle from 18/6 to 12/12. Every morning the plants were wilted. It took me ~ 2 weeks to realize the problem was that the Sentinel timer needed to be set for 24 hours, but comes preset from the factory at 12: 12 hours without nutes was causing the roots to dry out, consequently the plants were wilting.

Out of desperation to save these plants, I quickly tossed together a F & D rig with hardware I had on hand. Since I did not have a conventional F & D tray, I used a 18G Rubbermaid tote, which is much deeper than flood tables. I ran a drain line to my outboard rez. I used a low pressure pump to flood. Since the plants had a root system I put them in 3" net pots and topped them with hydroton. These I placed near the bottom of the Rubbermaid tote and covered them with lava rock. I started out feeding them ~3 hours.

Brain Fart #1. Due to the fast draining of lava rock, combined with the fact that lava rock has a very rough texture with lots of tiny pockets, which are ideal to trap a bit of moisture, I decided to experiment and flood more frequently. Eventually I was flooding ~ 45 minutes (now use 1 hour) and the growth was/is "off the hook". (see photo from last (first) grow). The problem was, I had 3 plants in there and one plant quickly dominated the other two; I had no way to move (or remove) them as all were locked into the lava rock with roots intertwined.

It was about this time that I bought a bunch of Air Pots to experiment with outside and inside in case I wasn't able to solve my hpa issues.

Brain Fart #2 Instead of dumping a bunch of lava rock in the bottom of the Rubbermaid tote I decided next grow (this one) to fill the APs with lava rock, and put them inside the Rubbermaid.

Back to last (first) attempt: As I was cobbling this rig together (with near dead plants) so I didn't waste time. I simply ran 1" pvc over the top of the tote, and let it flood (~ 3").

Brain Fart #3: Instead of simply letting the table flood to roughly 3"s, I decided to go all Bellagio and create a water show. I made a 'U" out of the pvc so that it ran the length of the tote. I drilled a bunch of small holes so that when the pump came on the nutes were streaming out of the holes while being aerated AND splashing on ~ 5" of the plant as well as top of the lava rock, working their way down through the roots. BAM!

Findings:

The high walls of the tote provide a rain forest like environment for young plants. They love the humidity, but probably only because the lava rock drains quickly, so they are not drowning in it.

Pics from first F & D attempt. The actual plant was over 7 ft. I snapped it at 3ft, ran it parallel to the table for anther 3 ft, then began LST curling it wround under the HO T5. It was over 7ft with ~ 10 3ft side branches

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Current F & D Pics

#2 was taken 4 days prior to # 2!

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Note pic #2 the plant in front is in small AP, sitting on a 6" platform. Yesterday I transferred it to a 1G AP by simply putting it (in tact) inside the 1G and adding lava rock around the sides. No replant shock or trauma!

At this moment the two method are running neck and neck-if anything the F & D primary leaves are a bit larger. This could be due to the rain forest environment. I could add sidewalls to my hpa to test. Time will tell, but based on my first attempt + what I am seeing now, there is no reason to complicate your grow with hpa, PLUS, it's a lot more expensive to assemble.

Lighting

Until LED achieves it's true potential for growing mj (it is getting better!) I am sticking with HO T5s. There are a couple cool threads on RIU discussing using them with bulbs from the aquarium industry, so I won't duplicate that here. UV Lighting is hard at work developing a line of bulbs specifically for horticulture. The beauty is bulbs are now available to optimize veg, while others for flower, consequently they can be tailored for either Indica or Sats. Plus, bulb changes are done with the twist of the wrist. This allows for one fixture to be optimal for either(or both) veg or flower.

I have an 8 bulb Quantum Bad Boy (432w), but if I had it to do over again I would get 2 @ 4 bulb, which provides more flexibility; makes it easier to supplement with both IR and UVb, which should each be in the center and on separate timers.

In veg

I only use 4-6 bulbs.

Quantum Grow bulbs + UVL AquaSun + Wave Point Coral Wave, CWs be replaced once I find small IR bulbs (< 40 watts) to run ~ 10 minutes immediately at lights out.

Flower

ZooMed FloraSun + UVL ASs + UVL Red Life + UVL 660 (no name yet)

I expect to flip to flower in ~ 2- 3 weeks max.

Stay tuned for weekly updates.

LP aero should be a lot slower than HPA, unless you overmist in a big way