Interesting facts that all growers should know!!

I've compiled a short note-form-type list of things I've been reading today that interested me. Mainly where Nitrogen, potassium, and phosphorous can be found in easily acquired foods or items besides store bought ferts.
Feel free to add your own interesting data but please refer to links. Thanks!

Important Nutrients:
Nitrogen = Ammonia
Potassium = Hardwood ash/lye, sodium free baking POWDER, Boiled Beans, small white, mature seeds,
Phosphorus = sodium free baking POWDER, Rice Bran, Roasted pumpkin + squash seeds, Flax seed

Acidity:
Soil is acidic when pH is less than 6 and alkaline when it is greater than 8. You can test, lower, or raise your ph using vinegar and baking soda.

Important Hormones:
Gibberellin hormone = Makes plants Tall
Cytokinin like Zeatin = Makes plants Bushy
Each inhibits the other

Nutrition Data:
SELF Nutrition Data
Potassium Essentials

Home pH Soil Test using vinegar and baking soda:
How To Test Soil Acidity/Alkalinity without a Test Kit
How Can I Make My Own Soil PH Test?
Vinegar and Baking Soda to Increase and Decrease PH in Soil

Plant Hormones:
PLANT HORMONES, NUTRITION, AND TRANSPORT
Types of Plant Hormones
Florigen Coming of Age after 70 Years
Plant hormone, From Wikipedia

A tropism is a growth response of a plant to an external stimulus.

Phototropism = The growth response of a plant in response to light direction.
Positive Phototropism = Growing toward the light
Negative Phototropism = Growing away from the light

Geotropism = The growth response of a plant in response to gravity.
Positive Geotropism = Growth towards gavity
Negative Geotropism = Growth away from gravity

Red light induces positive phototropism in roots.
Blue light induces negative phototropism in roots.
Roots exposed to blue or white light for long periods of time will grow algae and die shortly after.

Below you'll also find a chart which shows what lights have how many lumen/Watt and other facts.

Phototropism
What are positive and negative geotropism?
Root phototropism
Gene profiling of the red light signalling pathways in roots
Lumen per Watt Chart