Also, these plants were grown indoors completely under artificial light that outputs about 60 watts. The entire unit requires about 65 watts and runs for about 16 hours every 24 hours. It costs about 9 cents a day to run it.
When I first wrote this instructable it was about a month before I planted anything in it. Since then I have made many modifications to the hydroponics system such as a third light and a more advanced electrical system. I'm soon going to make a fabric cover for it with built in fans for air circulation. As a result you'll see some old and new pictures mixed together. Please bear with me untill I find enough time to re-write the whole thing.
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Signing UpStep 1: Warning Science Content: An Introduction to Plant Physiology
They exist in two very separate yet two very interconnected and equally important worlds. There is the above ground world of the shoot system and the underground world of the root system.
The shoot system of the plant is what we normally see when we look at a plant in the ground. From figure 1B you'll notice that the shoot system is extensively branched to allow a maximum surface area for the absorption of sunlight. This part contains the leaves, which is where the chemical reaction we learned in junior high takes place:
6 CO2 + 6 H20 ==> 6 O2 + C6H12O6
This chemical process is known as photosynthesis in which the radiant energy from the sun is harnessed and converted into chemical energy in the form of sugars. Excess sugars produced by the plant can be stored in bulk, usually in the form of a fruit that is meant to provide a developing seed with energy until it can grow it's own leaves and manufacture it's own glucose.
The process of photosynthesis is actually much more complex than the above chemical reaction. It is really a series of dozens of chemical reactions that are only a small part of a plant's overall metabolism, which requires many other nutrients such as Nitrogen, Potassium, and Phosphorus. But how does the plant collect these nutrients? From it's root system.
The root system is responsible for providing the leaves and the rest of the plant with the required raw materials for metabolism and photosynthesis. From figure 1B you'll notice that the root system is extensively branched to allow a maximum surface area for adequate absorption of water and nutrients from the soil. Anything that is absorbed by the roots are transported up to the leaves through the plant's stem. In return, some of the oxygen and sugars produced by the leaves are transported down to the roots through the stem. The roots are not exposed to sunlight and therefore cannot manufacture it's own sugars.
There are three main problems with soil that limit the growth of a plant:
One is that soil does not contain a whole lot of oxygen that the roots need to survive. Roots need to "breathe" just like we do and this can cause a lot of problems when oxygen is scarce. Hydroponics systems help with this by delivering a highly oxygenated nutrient solution to the roots. This is most commonly achieved through the use of air pumps and bubblers similar to those used in aquariums.
The second problem with soil it that nutrients are often scarce and in a form not usable by the plant. For example, nitrogen in soil is often in the form of ammonia or gas and must be processed by nitrogen fixing bacteria before the plant can use it. Hydroponics systems suspend the roots directly in a nutrient rich solution that can be readily absorbed by the roots and used for growth.
Finally, soil can contain many pathogens that can lead to diseased plants. Hydroponics solutions can be easily sterilized to prevent any nasty creatures from infecting your plants.
By addressing these three problems, hydroponics allows plants to grow and develop at an accelerated rate. With all that being said, I finally give to you my design of an indoor Deep Water Culture (DWC) hydroponics system.















































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I have a similar, but smaller system in my office designed to keep my office plants alive, eliminating the need for watering them.
I do however wonder: How to figure out when to add new nutrients to the solution or change the water. I only have 6 plants, but don't really know when they have used up all their nutrients - and i have not been able to find a way of measuring it? I usually just add some more when "I feel it is time" but I don't actually have any basis for making the assumption.
What do you guys do?
How do you figure out when to add more solution?
Is it better to entirely change the solution? (which i gather would be rather costly if it was a big system)
What I do for the math is take the ml/100L and multiply that by L water used.
So in this case
396/100 x 14 = 55.44 or 55ML
264/100 x 14 = 369.96 up to 37 ML
132/100 x 14 = 18.48 down to 18 ML
Awesome instructable, however, I can't seem to download it. Everytime it tries to load it just gets stuck or quits (times out) on me after 10 mins of nothing. Maybe I should take it up with the Instructables crew rather. What say you?
Would love to look at the instructable in full.
Thanks
J
Grampa Tom