# Indoor Hydroponics Cannot Feed You: The Math

I am sure this will get censored under the current conditions but it is a good read for anyone. I won’t say who this is meant for, he will just know.

The math behind why you cannot be effective about growing food indoors without either a nuclear reactor or the light of the sun.

The most efficient light bulbs will only convert approximately 15 percent of the input electricity to light. Of this light, you will be lucky if you manage to get more than 75 percent of it to your plants. This means, in an ideal setup, you will get about 12 percent of your input power to the plants in a usable form.

So 1000 watts in, equals 120 watts out.

From there, the plants will convert that light into energy to grow with at a rate of approxiately 5 percent. So just from a biomass perspective, that 120 watts will then become 6.

But there is another step – a large portion of the total biomass will not be edible. The edible portion, in a best case scenario will be somewhere around 50 percent, which takes your total energy available for you to eat at about 3 watts out of an original thousand.

Average people need approximately 100 watts continuous, day in and day out, to survive. Active people will need about 200.

So to get enough light into an indoor setup, you will need, just to stay docile, 100/3 = 33.3 x 1000, or 33,000 watts worth of spent electricity going 24/7 to get enough light to cause the plants alone to feed ONE man or woman.

The sun is enormously powerful, and in the central united states, during the summer, the sun will typically put 1,100 watts worth of energy into each square meter of land during the day, an amount of energy that would take 10,000 watts of input power to cause even an efficient light source to produce. That is why plants can support us. The process of photosynthesis can be enormously inefficient, and it will not matter because the sun can really deliver.

Bottom line? If you want to feed yourself with a hydroponic setup, you have to use a standard greenhouse.

This math is not exact because I went off of memory. But the overall answer is an accurate one.

http://farganne.wordpress.com/2013/01/17/indoor-hydroponics-cannot-feed-you-the-math/

## 2 thoughts on “Indoor Hydroponics Cannot Feed You: The Math”

1. pete says:

this is wrong.

modern hydroponics doesnt use MBF or SON-T lamps.
it uses led’s

the sodium lamps get too hot and the police can see the building on infra-red like a football stadium.
also you need to bypass the electricity meter to stop several 6-8Kw of lamps causing a red-flag with the power company.

in the last 3 years things have changed,
led’s are atleast 90% power efficient and can generate exactly the colour-spectrum needed by the plant making the optical efficiency almost 100%.

you also need forced-air cooling and extractors with sodium because of the lamp-generated heat and moisture.
not so with the led’s

2. James says:

That only fixes the first part of the equation. Photosynthesis is still only about 5 percent efficient. On top of that, five watts of LED lighting still costs over \$30. LED lighting is prohibitively expensive. The only way you would EVER incur such an expense is for growing pot. Food is an entirely different issue, and indoor food production without the help of the sun, for the purpose of getting calorie dense foods, is not a reality.

LED lighting is NOT 90 percent efficient. The fact that MIT produced a more than 100 percent efficient LED is not going to make a difference in a factory in China, and its 70 picowatt output would not grow a single piece of microscopic algea. The LED lighting you can buy right now is right around 16 percent efficient, and only beats Metal Halide by a few percent.