What's the Deal With Hydroponics?
I love traditional soil agriculture on small, well-managed pieces of land. But as the world's population booms, I find it very unlikely that permaculture and intelligent land management will be used to feed the world's population. Indigenous cultures pulled this off. But in the past 100 years or so we have done a highly efficient job here in America of destroying some of the richest topsoil on the planet in the Midwest. This is by introducing the most harmful chemicals and fertilizers that run off right into our rivers and cause algae blooms that turn our tributaries into fish graveyards by sucking up all the oxygen in the water.
I will always encourage permaculture and plan on writing many blogs on it in the future. But I cannot foresee it being implemented on a vast enough scale to feed our world in the coming decade and making the shift away from industrial agriculture that is needed to save us from ourselves.
I believe in the concept of appropriate technology, where you create and produce commodities as close to the place of use and consumption as you can and empower people locally. When you live in rural communities, permaculture and sustainable agriculture and land management are ideal. On suburban plots of land, I believe in small, diverse sustain ably managed plots and greenhouses. In a urban area, horizontal space is not an availability and to address the needs of an extremely dense population, I think we need vertical farming; greenhouses on top of grocery stores and buildings, and green roofs.
Soil is far too heavy for many of these applications and creates its' own problems.
Hydroponics has been proposed increasingly to help curb these issues. Futurists have long drawn up pictures of skyscrapers reaching to the sky covered in vegetation and housing vertical hydroponic farms. Is this a pipe dream or possible?
Well the reality is more and more small companies entering the market to grow plants this way and be cost competitive with traditional agriculture proclaiming its sustainability benefits.
But what exactly is hydroponics?
Hydro (water) Ponics (working) The greek breakdown of this word means "waterworking", so supplying all that the plants need through water.
No soil is used. Soil is just a medium for holding nutrients and water for the plants and the biology in the soil is also beneficial.
There are different variations of hydroponics from plants sitting in cups on a foam raft with their roots in the water, to "gutters" where water is pumped up and flows in a thin stream past the roots, to systems where the plants are supported in a medium and periodically "flooded" on a timer. One more creative way is in "aeroponics" where the roots are simply misted with a nutritious aerosol mist of water and fertilizer.
Fig 1: Hydroponic "Raft" System
Fig 2: Hydroponic gutter or "NFT" (Nutrient Film Technique) System
Fig 3: Hydroponic top irrigation "flood" system
Fig 4: Aeroponic cut-a-way
In hydroponics, the roots are usually supported in some way or the plant is supported and the roots hang.
The "supporting material" in hydroponics can consist of things like:
gravel (lava rock is best because it is porous and light)
clay pellets (hydroton)
Some will definitely always prefer soil believing humans will never be as good as nature at deciding what a plant needs, but as we face issues of large populations needing food, hydroponics does allow us to use water much more efficiently, even growing plants in the desert.
This is because you can recirculate the water and can have many uses from it before treating it through grey water collection and using it all over again.
You can grow the plants indoors and manage and eliminate issues with pests, even introducing beneficial ones like ladybugs.
It is easy to keep equipment clean and sterile and stop and isolate the spread of plant diseases.
There are many different ways that hydroponics can work, the easiest being a plant in a jar in your kitchen.
Yes that "lucky bamboo" growing in that jar on your counter is hydroponics. Wonder why it's yellow or sad looking? Well, plants still need sunlight.
People today seem to be forgetting basic science classes in elementary school. Someone asked me why their succulents hidden on their bookshelf in a dark corner of the house weren't looking so hot...
Plants need sunlight!!!!! And succulents need lots of it. :/
If you do not have sun or want to grow indoor and/or control the light levels, different types of artificial lights work well.
Fluorescent works well for plants like lettuce and leafy greens as well as herbs as they do not need super intense light.
Fig 1: Florescent Grow Lights
For better energy efficiency and more color varieties, (you can use cool and warmer colors to affect different outcomes in plants) you can opt for LED lights. These are some of the newest grow lights on the market, but can be much more expensive.
Fig 2: LED grow lights
Pressurized sodium and other stronger output variety lights are used for fruit-bearing plants like tomatoes, peppers, and cucumbers. Fruit-production takes a lot of energy for a plant and that is why fruit is produced in the long-sunlight days of the year. These are expensive, require power conditioning equipment, and use lots of energy as well as putting off a lot of heat.
Fig 3: Pressurized Sodium Light
Plants need air as well..
An air stone adds the oxygen component that plants need to uptake in their roots as well. If your system has a drop in elevation like a little waterfall and plashes this is oxygenating the water as well. Plants will not ever be happy in stagnant water, that is a good rule of thumb. Create some water turbulence when designing a system.
Fig 1: Air stones and a pump add needed oxygen to the system
Fig 2: An aquarium is an excellent demonstration of what is needed in a hydroponic system. Tanks have an air stone and pump, a filter and the filter flows back into the tank as a small waterfall making turbulence which in turn further oxygenates the water. Not many fish will thrive without this. Most fish will not like a stagnant body of water except for fish like betas that evolved that way.
Plants also need nutrients which brings me to my biggest issue with hydroponics and one I will address much more in depth in the future in hydroponic alternatives.
A lot of the hydroponic stores are like head shops that say "we sell bongs for tobacco!!"
Everyone knows a lot of the equipment is used for marijuana, devil's lettuce, wacky tobacky, ganja, weed, chronic, or jazz cabbage as someone said recently to me. (I got a good laugh from that one!)
Much of this market wants very specific traits in plants, so they sell a lot of chemical (mostly liquid) fertilizer that is then added to a reservoir and circulated through the water to the plants.
I do not like synthetic fertilizers and luckily you can get your fertilizer through other alternative sources that may be carried at hydroponic stores, but will definitely be carried online.
These can be things like:
tea made from compost
Most water reservoirs on these system now consist of plastics, but can also be made of;
concrete, glass, metal, vegetable solids and wood.
The containers should be covered to keep algae from multiplying (they need sunlight as well). All tubing should be dark to reduce algae growth or if clear tubing is used, you will need to flush it out every so often. "Plant bibs" are sold made from coconut husk or plastic to reduce algae growth in the plant mediums. (Especially with Rockwool) Algae needs lots of moisture and Rockwool's strength is that it is good at holding moisture and its weakness is that it is extremely good at holding moisture!
More to come on more topics and....
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