it amazes me how many people turn their nose up at this because someone mentions 'piss'. Piss being something we associate as a waste product and therefore considered bad.
mammal urea (of which we can count ourselves a part of) is widely used in the fertilizer industry as well as being a major player as a key element in the making of most chemical fertilizers too.
So organic or not, your probably getting urea in your nutes anyway.
I've experimented with it a bit and found the best solution is when you've drank plenty of fluids, perferably not sodas. Had a few occasions where it has been used as a band-aid to a struggling young'un with impressive results.
The standard crop-nutrient rating of urea is
46-0-0.
source: ICIS,
http://www.icis.com/v2/chemicals/9076559/urea/uses.html
Urea [CO(NH2)2]2
Urea is a manufactured, organic compound containing 46% nitrogen, that is widely used
in solid and liquid fertilizers. It has relatively desirable handling and storage
characteristics, making it the most important solid nitrogen-fertilizer material, worldwide.
It may contain small concentrations of a toxic decomposition product, biuret; however,
urea manufactured using good quality control practices rarely contains enough to be of
agronomic significance. Urea is converted to ammonium carbonate by an enzyme
called urease when applied to soil. Ammonium carbonate is an unstable molecule that
can break down into ammonia and carbon dioxide. If the ammonia is not trapped by soil
water, it can escape to the atmosphere. This ammonia volatilization can cause
significant losses of nitrogen from urea when the fertilizer is applied to the surface of
warm, moist soils, particularly those covered with plant residues (no-till) or those drying
rapidly. Relatively high surface pH also aggravates nitrogen volatilization from urea.
(See section "Additives for Nitrogen Fertilizer.")
Efficient Fertilizer Use — Nitrogen: Dr. Don Eckert
source:
http://www.rainbowplantfood.com/agronomics/efu/nitrogen.pdf