Aquaponic Gardening

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Threadjackers Bob and Chris getting carried away on another thread, so I figured I'd move it over here (seems more at home here than the threadjackers group)

http://community.theaquaponicsource.com/group/sacramento-aquaponics...

Question here is use the use of fresh pee or bagged urea, as opposed to aging the urine until it converts to ammonia (humonia) before adding to system. True, urea needs to be converted, but won't it simply be converted anyway if added fresh? Does it take longer? And even if it takes longer, once proper organisms are established, won't stability be achieved?

Also, bagged urea lists only N on the NPK. Does humonia contain more macro and micro nutrients than bagged urea?

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The main reasons for aging the hummonia before using it to cycle up a system is because you can't really measure how much you have added if you add it fresh.  As in you won't get an ammonia reading after peeing in the tank even though you may have added plenty, this leads to people tending to over dose when using fresh urine or urea.

Also, aging the urine will kill certain very common pathogens (like e. coli that is on and in pretty much everyone, bottling and aging the urine till the pH reaches 9 seems to be a very easy way to kill the e. coli)

Yes urine contains other nutrients including phosphorus, potassium and micro nutrients.  I'm not sure what else bagged urea contains but probably not much phosphorus or potassium though I'm sure there are some other trace element impurities though I'm not sure how desirable some of them would be in aquaponics if used heavily.  At least with the pee, you know you are not adding anything that you were not willing to put into your body in the first place.

Good points, TC. The dissinfecting factor alone is worth the effort for pee. Funny how I forget basic things when I'm focussing on something else. Still, fresh pee could still be used for cooked crops, or non-edible crops, or even edible if the grower just doesn't care. Bagged urea, I'm assuming, must certainly have had some dissinfecting process before being bagged? Actually, until this moment I assumed bagged urea must be produced from animal urine, so I'll have to verify that assumption. And if it is animal urine, wouldn't it have the K and P (at least similar) that human urine has?

I agree with what you have said.  My system is about 700 gallons total with about 20 cu ft of gravel.  I have rarely been able to over dose this system with all the pee I produce in a day,  I did water tests on this system just like I do on my aquaponic system, and keeping it in range was never a problem.  If Ammonia crept up I would not add urine that day and it returns to zero Ammonia by the next day.

The Urea I bought looks very pure.  Probably not much in the way of trace minerals left in it.

Just for the record I am using Urea only because I can't produce enough urine to conduct an experiment to find out how much Nitrate the tomatoes, and basil can handle. Does anyone already know what level of Nitrate can burn the plants?

I started doing peeponics because it seems natural, and I suspect the urine contains trace elements.  Aging urine is of course the right way to go, but it's bothersome, and I'm healthy.  I doubt I will spread pathogens. 


TCLynx said:

The main reasons for aging the hummonia before using it to cycle up a system is because you can't really measure how much you have added if you add it fresh.  As in you won't get an ammonia reading after peeing in the tank even though you may have added plenty, this leads to people tending to over dose when using fresh urine or urea.

Also, aging the urine will kill certain very common pathogens (like e. coli that is on and in pretty much everyone, bottling and aging the urine till the pH reaches 9 seems to be a very easy way to kill the e. coli)

Yes urine contains other nutrients including phosphorus, potassium and micro nutrients.  I'm not sure what else bagged urea contains but probably not much phosphorus or potassium though I'm sure there are some other trace element impurities though I'm not sure how desirable some of them would be in aquaponics if used heavily.  At least with the pee, you know you are not adding anything that you were not willing to put into your body in the first place.

I've had nitrates off the scale on the freshwater master test kit and never had fertilizer "burn" on the plants.  I think the problem with fertilizer burn in garden or hydroponics is more to do with the salts than the actual nitrogen content.  That said, pure ammonia or huge amounts of something that turns into ammonia put into a system that doesn't have a cycled up bio-filter might cause harm to the plants due to ammonia burn (I've only really heard of signs of this when people keep dosing and dosing in a brand new system with fresh urine or urea because they don't get an ammonia reading right away and several days later the ammonia starts rising and rising as the urea starts converting and by then it is horribly overdosed and the ammonia levels wind up off the chart and often stall or severely slow the initial cycle up.)

Bob, I don't know about burning from nitrogen, but I do know my local hydro friends grow tomatoes with an excess of N to produce thick, crazy almost mutant fast veg growth, which makes lousy tomatoes if any at all. Once the plants get massive, they pull back on the N and boost K (probably P too), which turns the giants into tomato producing machines. Once the fruits start to ripen, they balance out the mixture (I think) and INCREASE the EC to produce a dehydrating effect, which helps set the sugars and make the tomatoes actually taste good. All the old farmers do exactly this with their dirt toms, by fertilizing and watering heavy in the early part of the season, and dry farming them when fruit sets. Mmmmmm. Nothing better than dry-farmed toms. This is the reason AP tomatoes are mediocre in flavor. And too high an EC in hydro gets the dry farming effect. I'm going to try a little experiment this fall with my tomatoes and trying to dehydrate my ripening plants using seawater (and brackish fish like Sac perch, good in salinity up to 15 ppt), but that's another story.

Definately, though, hydro growers can manipulate flowering, fruiting, and flavor by altering nutes. And high N is only part of it. I'll post a picture here tonight of what high N does to a tomato plant, just took some good ones Saturday.

Thanks to both TC and Jon, I will discontinue the experiment.    I actually bought the Urea to burn out a patch of Bamboo

My AP tomatoes taste better than my in ground tomatoes.  They taste like they have a little salt on them.  Early in the season I gave them a big helping of Epsom Salts.  I don't know, but that might have something to do with it.

Maybe the magnesium helped, Bob. I've heard it has a sweetening effect, and I want to try some on my watercress, which right now is especially sharp from a KCl dose. I've never added Epsom salts. And without a doubt, your testimony is the first I've ever heard of better toms in AP than soil. It certainly isn't the case with mine. My AP tons are comparable to market produce. My soil toms are mouthwatering. I'm curious how Vlad's recent harvest turned out, taste wise.

Yes good point on the disinfection. Thought I read human urine was effectively sterile however, at least fresh out of the bladder. It breeds bacteria like crazy after that though so I guess it doesn't matter how it is brought into the outside world.

Assuming everything on wikipedia is true, looks like there is quite a bit of industrial urea manufacturing on the order of 100M tons a year. It is also the primary ingredient of Miracle Grow products so even if it was derived from urine, it is likely highly refined for control reasons.

Just a guess when/if animal effluent is treated/reprocessed it is done on a whole as a slurry. Since urea doesn't seem to be that stable on it's own in solution they are likely targeting the N content as ammonia.

My cherry tomatoes are very sweet. 

My in ground Early Girls began to ripen weeks before the PeePonic Early Girls even though the in ground do not get afternoon sun.  They were planted in a flower garden which I added worm compost to last year, so the soil was not optima, but pretty good, and they get a lot of water in that flower bed. 

By the way, as you suggested, I've come to enjoy the bitter taste of Water Cress 

Ha! I thought you would.

So commercial urea is synthetic, made from ammonia and CO2, not made from urine. And the commercial ammonia is of course also sythetic, made from atmospheric N fixed with petroleum. That explains the absence of K and P. It is processed as urea because it is the lightest form of concentrated N, and thus cheapest to ship and store. It also has benefit in taking some time to change to nitrates, which are very mobile in soil and susceptible to leaching away.

Hey guys, I have to admit I have not the time to read this entire thread in detail right now, but skimming through it seems like some good points are raised (as could only be expected considering the "usual suspects" present :). 

Bob, I'd only like to add that you think about biuret...and hope that the bag you purchase indicates that it is at least "low biuret" urea.

ALL chemically synthesized urea contains either more or a lesser amount of biuret. It is an impurity inherent to the process. (Chemically synthesized urea, the kind you buy in a bag from a store as fertilizer)  It will stunt or harm crops (the biuret). Say, that is the reason only "low biuret urea" should ever be foliar fed, and never the 'regular' stuff, as it can (and often seems to) be harmful to plant health/growth once it accumulates beyond a certain point (as it would when foliar feeding).. How or if this plays out in AP is anyone's guess. Just keep that (the possible effects of biuret in your system) in mind during your experiment. I'm betting the biuret affects your plants before some excess of nitrates ever will. 

Gotta go...

Jon, You mentioned elevating "EC" in one of your posts. Can you explain the abbreviation?

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