Hydroponics Enlightenment
Deep Pool Floating Raft
Sounds like a higher consciousness, martial arts film — but no, Grasshopper — it is the technical name of one of the methods for the commercial growing of hydroponic crops like lettuce.
Starting in the Germination Zone, lettuce seeds (previously coated in clay which holds in moisture to nourish the seed then breaks apart easily to let the seed sprout), are poured into a steel tray connected to a vacuum hose. The tray has 276 holes, the vacuum sucks a seed into each hole. Next they take a foam block, called “an oasis”, which has corresponding holes, (each in the center of a break-away section), positioning it upside down on top of the tray so that a quick flip deposits a seed into each hole of the oasis. The oasis is set on a conveyor belt where the seeds get their first watering on the way to the pool.
The oasis is set afloat in a pool of water about 12 inches deep (30.48 cm). Technicians continuously monitor and adjust the pool’s level of oxygen and fertilizer, which is the key to hydroponic growing. The water is never discarded, only topped off to replace water the plants use and evaporation.
On the first day, the seeds are watered frequently. Within a couple of days the seedlings start to appear and are watered and fertilized by overhead nozzles. Around the fourth day significant sprouting is apparent, again the plants are watered and fertilized.
The first leaves emerge on about the 7th day in summer, and about the 11th day in winter, less sun in the winter causes a slower growth rate. At this point, the first of a series of transplants occur. The 276 plant sections of the foam oasis are separated and each are placed on a styrofoam board which holds 288 plants. They are then set afloat in the Nursery Zone.
About the 13th day in summer or 20th day in winter, the second transplant occurs. The plants are tranfered to another styrofoam board with 72 holes. By now the roots have grown through their section of the foam oasis. To avoid damage, hooks are used to guide the young roots of each plant through it’s hole in the board. This gives the plants more light, room to grow and develop a healthy root system to absorb water and nutrients.
The last transplant occurs around the 26th day in summer, 45th day in winter. The plants now go from 72 hole board to one with just 18 holes. Using the same hook method as before (although a little harder to manipulate because of the longer roots). The lettuce is then floated to the Production Zone, the last move before harvesting. The production zone pools are bigger so automatic machines move the boards around.
About the 45th day in summer or 75th day of winter, the lettuce is finally ready for harvesting. The yellowed leaves at the base are cut off and the roots are either cut off or wrapped around the stem, depending on how the crop is sold. Then each plant is vacuum cooled for longer shelf life.
This hydroponic system produces 500 plants per square yard (0.91 m). Almost 5 times the yield of field grown lettuce. Plus it is much safer for people and the eco-system because there is no need for pesticides or fungicides. And because it’s all indoors, fertilizers doesn’t get out to contaminate the environment.
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Tags: Agriculture, fertilizer, garden, Hydroponic, lettuce, Nutrient, Plant, Seed

















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April 10th, 2009 at 12:22 am
Linda, I think this hydroponics technology can still be improved, as 500 plants per square yard (0.91 m) is not too much, due to the drastically population increase rate year after year…
wilsons last blog post..Beware of The Germs That Hide inside the Overnight Water!
April 10th, 2009 at 9:25 am
Hydroponics Enlightenment | Forced Green…
one of the methods for the commercial growing of hydroponic crops like lettuce….
April 10th, 2009 at 9:55 am
Hi Wilson … You are right. I am sure there are bigger ways to do this but this was just to educate us on how it can be done.
April 10th, 2009 at 10:41 am
WOW…that look amazing
April 10th, 2009 at 4:56 pm
Hi Miss Pidgin … It is pretty amazing. Thanks for coming by.
April 10th, 2009 at 7:47 pm
This looks awesome. I always love learning the new techniques in Green technology you write about. Glad to be back blogging too.
yanjiarens last blog post..My Wedding Suit is Green.
April 10th, 2009 at 8:43 pm
I’ve long been fascinated by hydroponics. Such a nice clean way to grow fruits and veggies!
Barbaras last blog post..Relax with Barbara On Wednesday 32
April 10th, 2009 at 8:58 pm
Hi Yanjiaren … Long time no hear! Hope your back is better! Glad to have you back.
April 10th, 2009 at 9:01 pm
Hi Barbara … I agree. I have been always inquisitive to this way of gardening. To me, it is a very cool way to do it.
April 11th, 2009 at 2:10 am
Hi Linda,
I think this is a fabulous way to garden. Not having to use pesticides, reusing the water, and the growing time – is that shorter than normal, or not?
I’d much rather buy hydroponic crops too. They just seem more “sanitary”.
Another great green lesson. Thank you Linda.
Barbara Swaffords last blog post..Give Your Readers What They Want
April 11th, 2009 at 8:37 am
Hi Linda…we just started an aquaponics system in our back yard, in which we use an old above ground swimming pool stocked with Tilapia. The water is piped from the fish to 55 gallon barrels that are cut in half and filled with clay and vegetables. Then the water is filtered through the clay and back into the fish pond! It’s been a real fun project! We also have lettuce plants floating in styrofoam on the fish pond, it’s growing great! Thanks for the great information!
~Wind
Winds last blog post..Babcock Ranch in Florida will House a ‘Green City’
April 11th, 2009 at 9:33 am
This is a great way to garden! I’m setting up hydroponics for growing indoors year round in the house so am just doing the research now. Thanks for the information.
Garden Gnome Wanderingss last blog post..Tips for Growing Herbs
April 11th, 2009 at 9:43 am
I love to go to Epcot and see their hydroponics. I never really thought about doing it at home though Garden Gnome…good luck.
Shanes last blog post..The Dirty Dozen – The 12 Most Contaminated Fruits and Vegetables
April 11th, 2009 at 10:11 am
Hi Wind … What a great idea! So ingenious plus you have at least a couple of meals right there ready to be used. Thanks for sharing.
April 11th, 2009 at 10:12 am
Hi Garden Gnome … Here’s to wishing you luck in your new project! Please let me know how it works out for you.
April 11th, 2009 at 10:14 am
Hi Shane …. that is where I really got interested in hydroponics. Epcot is a place of many ideas and inventions. I would also like to start a hydroponics garden when I get a few moments to think!
April 11th, 2009 at 1:11 pm
That was really interesting. I’m curious to know if there’s any high volume operations out there. Now that I think of it, I have seen Hydroponic boston lettuce at the grocer. I wonder how amenable other veggies are to being grown like this?
Greener Pasturess last blog post..Should I Refinance? Obama Says Yes.
April 11th, 2009 at 1:15 pm
Hi Barbara … The grow time is shorter and with the example above, the lettuce grown here is 5 times more than in the soil with the same yard.
April 11th, 2009 at 1:33 pm
Hi Lisa … Yes, you can grow tomatoes, peppers, cucumbers, herbs, flowers, and strawberries. And Yes, there are several high volume hydroponic growers out there. The world’s largest grower is Eurofresh farms in Wilcox, Arizona and its main product is tomatoes.