Passive Hydroponics requires the least effort of any other
hydroponic technique. It is, simply, hydroponics without the use of
electricity. The implications for this technique are seen throughout the world.
In rural areas of the world with little access to water, the water-saving
capabilities of hydroponics has increased crop yield, and improved the lives of
millions. Since lack of electricity and water go hand in hand, the most common
technique used is some variation on Passive hydroponics. In India, for example,
cotton is a readily available material, so it is used in this sub-technique:
wick type.
Yes, that was an awful segue; anyway the first, and simplest
type of passive hydroponics, is “wick type”. A wick, like a candle wick brings
liquid from a lower position to a higher position. This works using the process
known as capillary-action. Though this piece of physics is fascinating, just
like all natural processes, it is beyond the scope of the blog to discuss it.
So, Bing* it. The systems have a nutrient reservoir below the medium, and a
wick, such as one made of cloth, wicks the aqueous solution up to the plant
roots. I have made this type, but I was not very successful—or really at
all.
The second type of Passive
Hydroponics is known as a reservoir system or Deep Water Culture—often shortened
as DWC. This system I have also done, with varied success.
This is one example of success. The lettuce turned
out very bitter, because of how the lighting—or lack thereof—made it grow, and
it was grown in summer. This was grown inside. I attempted to make another system,
but while cutting the top, I cut through the bottom—if you can’t imagine how
that’s possible, then you obviously have more common sense than me. (I cut it
the top with a sharp knife using the container, which was going to hold water,
as a platform.) The system shown actually
uses a bit of electricity other than the electricity needed for the light. I,
wisely, broke the rule about not using electricity by adding an aeration stone.
Perturbing the water dissolves O2 in the water—which the plants need
for respiration. The roots go down into the water, to extract nutrients from
the solution. In this case, it had enough diatomic-oxygen present to sustain respiration.
In a system true to the point of passive hydroponics, the nutrient solution
would gradually be used, while the upper roots specialize in extracting O2.
So, it is entirely possible to make this kind of system for outside use, but most
results show that an aeration stone drastically improves yield.
The
third major type of passive hydroponics is the self-watering-container concept.
Water resides in a local reservoir, hidden from light, and a significant
portion of the container contains media. This media must wick water. These types
of media include: perlite; coconut coir; peat moss; pumice; and, to a certain extent,
lava rock/Basalt (I’ve worked with it before).
I have a lot of experience with all these forms. The
one thing that is most important is the choice
of media. The media will make or break your system. What you need is a
water-retentive media. Depending on your want of manual labor, the media can be
shortchanged for cost, to a certain extent. If you have enough time to water
every system, every day or so, then go ahead. However, I’d rather water about
once a week—or once. These systems can be created. In fact, I am currently designing
two low–maintenance systems. Coupled with a pH buffer, the work is very
minimal.
The best types of systems for this are some kind of
compromise between #2 and #3. These systems are not terribly complicated to construct
either. The tools and materials for one such system—very successful—are as
follows:
- Media—I choose
LECA/Hydroton or perlite for this system
- 5 gallon bucket
- A hand-operated screw
driver
- A larger container
- A trash bag
The process for constructing this is also very
short:
- Puncture holes 5 gallon
bucket with a screw driver
- Fill the bucket with
media
- Fill the larger
container with water
- Put a supporting piece
of plastic, wood, etc. on the larger container
- If using a trash bag,
rip the trash bag to allow the 5 gallon bucket to go through it
- Place the bucket,
filled with media, into the water
- If needed, stabilize the
bucket with tape.
- Make sure the metal
part of the bucket is not in contact with the water
- Plant
After construction, it should look like this:
Another, even simpler system was “developed” at the
same time, last year.
Materials:
- Media—I (unwisely)
chose basalt for this last year. I’m doing perlite this year.
- 5 gallon bucket
- Trash bag
Procedure:
- Fill the bucket with
1/3 water
- Put the trash bag in
the bucket
- Put the ends around the
bucket so that the trash bag envelopes the bucket
- Make sure the trash bag
is tucked around the bottom of the bucket
- Poke holes in the trash
bag with anything—even your finger will work
- Fill with media
It should look like this:
(You’ll notice
the hydroponic system did worse. It did initially, but after I stopped being
stupid and watered above the media/root line, the hydroponic tomato plant
produced more tomatoes. The reason for why the plant didn't grow well without
water above the root line was that it did not finish growing roots into the reservoir.
Once it did, I did not have to water it for weeks in the heat of august. I’ll
just call it a learning experience.)
*I live in the Pacific Northwest, I'd be a "traitor" to not respect the MSFT overlords.
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